2005, 79(2):944. DOI: 10.1128/JVI.79.2.944-954.2005.J. Virol. Richard L. WardBasu, Michael J. Cole, Pyone P. Aye, Rudolf P. Bohm and Monica M. McNeal, Karol Sestak, Anthony H.-C. Choi, Mitali P GenotypeHomologous Wild-Type Rotavirus of a NewModel in Rhesus Macaques, Using a Development of a Rotavirus-Shedding

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JOURNAL OF VIROLOGY, Jan. 2005, p. 944–954 Vol. 79, No. 20022-538X/05/$08.00�0 doi:10.1128/JVI.79.2.944–954.2005Copyright © 2005, American Society for Microbiology. All Rights Reserved.

Development of a Rotavirus-Shedding Model in Rhesus Macaques,Using a Homologous Wild-Type Rotavirus of a New P Genotype

Monica M. McNeal,1 Karol Sestak,2 Anthony H.-C. Choi,1 Mitali Basu,1 Michael J. Cole,2Pyone P. Aye,2 Rudolf P. Bohm,2 and Richard L. Ward1*

Cincinnati Children’s Hospital Medical Center, Cincinnati, Ohio,1 and Tulane National Primate Research Center,Covington, Louisiana2

Received 22 June 2004/Accepted 1 September 2004

Although there are several reports on rotavirus inoculation of nonhuman primates, no reliable model exists.Therefore, this study was designed to develop a rhesus macaque model for rotavirus studies. The goals wereto obtain a wild-type macaque rotavirus and evaluate it as a challenge virus for model studies. Once rotaviruswas shown to be endemic within the macaque colony at the Tulane National Primate Research Center, stoolspecimens were collected from juvenile animals (2.6 to 5.9 months of age) without evidence of previousrotavirus infection and examined for rotavirus antigen. Six of 10 animals shed rotavirus during the 10-weekcollection period, and the electropherotypes of all isolates were identical to each other but distinct from thoseof prototype simian rotaviruses. These viruses were characterized as serotype G3 and subgroup 1, propertiestypical of many animal rotaviruses, including simian strains. Nucleotide sequence analysis of the VP4 gene wasperformed with a culture-grown isolate from the stool of one animal, designated the TUCH strain. Based onboth genotypic and phylogenetic comparisons between TUCH VP4 and cognate proteins of representatives ofthe reported 22 P genotypes, the TUCH virus belongs to a new genotype, P[23]. A pool of wild-type TUCH wasprepared and intragastrically administered to eight cesarean section-derived, specific-pathogen-free macaques14 to 42 days of age. All animals were kept in a biocontainment level 2 facility. Although no diarrhea wasobserved and the animals remained clinically normal, all animals shed large quantities of rotavirus antigen intheir feces after inoculation, which resolved by the end of the 14-day observation period. Therefore, TUCHinfection of macaques provides a useful nonhuman primate model for studies on rotavirus protection.

Rotaviruses are the primary cause of severe diarrhea inyoung children and are responsible for ca. 500,000 deaths inthe world each year (35). Several vaccines against rotavirusdisease have been developed, but none are available for rou-tine immunization (48). All candidate vaccines evaluated inclinical trials have been live, attenuated rotaviruses that aredelivered orally to mimic natural infection. Although naturalrotavirus infection has been found to provide substantial pro-tection against rotavirus disease, particularly severe disease,the mechanisms by which this occurs remain largely undeter-mined (45). A number of animal models have been developedto help understand the mechanisms of rotavirus immunity,including lambs (40), calves (4, 12, 33, 53, 54), piglets (3, 5, 17,18, 56, 57), rabbits (7–10), and rats (6, 16), but the majority ofthe mechanistic studies have been conducted with the adultmouse model that we developed in 1990 (51). Even with thesemodels, only a partial understanding of the mechanism ofrotavirus protection has been achieved. Furthermore, an ani-mal model that more closely resembles humans is clearlyneeded, both to understand the mechanisms of rotavirus im-munity and for preclinical evaluations of novel rotavirus vac-cine candidates.

Nonhuman primates are the animals most closely related tohumans. Although several rotavirus challenge studies havebeen conducted with these animals, the first of which was

reported in 1976 (55), very little is known about rotavirusinfections in any nonhuman primate species. Several investi-gators have reported that oral inoculation of different nonhu-man primates, including several types of monkeys as well asbaboons, with either culture-adapted simian (SA11) or human(Wa) rotavirus or fecal preparations of human rotaviruses, willcause diarrheal illness in most animals during their first weekof life (21, 23, 26, 31, 36, 41, 55). However, after that time,essentially no illness was observed, and most of the older an-imals neither shed virus nor seroconverted. The exception mayhave been the results found after inoculation of one chimpan-zee that, when orally administered SA11 at 141 days of age,developed diarrhea and shed large amounts of rotavirus over a9-day period (41).

A potential major limitation in these studies was the lack ofa challenge virus that would reliably infect and produce illnessin the nonhuman primate species under investigation. The onlysimian rotavirus used in these studies (SA11) was obtainedfrom an asymptomatic vervet monkey (27) and has been re-peatedly passaged in cultured cells, a method typically used forviral attenuation. The only other rotaviruses used were humanstrains. Although rotaviruses sometimes cross species barriers(32), their virulence is typically blunted in heterologous hosts.Thus, these human strains, even those from human fecal spec-imens, are likely to be naturally attenuated in nonhuman pri-mates. There has been no report of experimental inoculationof a nonhuman primate being performed with a wild-type (fe-cally derived) simian rotavirus. Therefore, it was possible thatwild-type simian rotaviruses may produce severe illness in non-human primates after the first week of life, perhaps even up to

* Corresponding author. Mailing address: Division of InfectiousDiseases, Cincinnati Children’s Hospital Medical Center, 3333 BurnetAve., Cincinnati, OH 45229. Phone: (513) 636-7628. Fax: (513) 636-0950. E-mail: dick.ward@cchmc.org.

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several years of age as occurs in humans. The first purpose ofthis study was to obtain and characterize such a virus fromrhesus macaques to be used for challenge studies in nonhumanprimates. The second purpose was to determine whether thisnew strain of simian rotavirus could consistently produce highlevels of fecal rotavirus shedding and possibly elicit diarrhealdisease in macaques when administered after the first week oflife. If either or both outcomes could be attained, this modelsystem could potentially provide a highly relevant substitute forhumans in studies on active immunity against rotavirus.

MATERIALS AND METHODS

Rhesus macaques: sample collections and illness monitoring. (i) Conventionalanimals. A group of 16 juvenile rhesus macaques (Macaca mulatto), age 2.6 to5.9 months at the time of their enrollment on 12 November 2002, were includedin a study to obtain wild-type rotavirus from naturally infected animals. Allanimals were born at the Tulane National Primate Research Center (TNPRC)and were housed under biosafety level 2 conditions in accordance with standardsof the Guide for the Care and Use of Laboratory Animals and the Associationfor Assessment and Accreditation of Laboratory Animal Care. Only simianretrovirus (simian immunodeficiency virus, simian retrovirus, and simian T-cellleukemia virus)-negative animals were used. Every animal was monitored fordiarrhea and signs of lethargy on a daily basis. Initially, blood samples werecollected and sera were harvested and stored (�20°C) until analyzed for rotavi-rus immunoglobulin G (IgG) and IgA. Once these were determined, the 10animals with the lowest titers were monitored for rotavirus shedding from 25November 2002 through 6 February 2003. For this, stool samples were collectedtwice per week from the bottom of the cage containing each animal and storedat �80°C until tested for the presence of rotavirus antigen. Monthly bloodcollections were also taken from these 10 animals, and the harvested sera werestored (�20°C) until analyzed for rotavirus IgG.

(ii) Cesarean section-derived animals. Two groups of cesarean section-derivedmacaques were used. All were lactogenic immunity deprived (hand fed and freeof maternal secretory IgA) and housed in nursery (biosafety level 2) rooms thatcontained only specific-pathogen-free juvenile animals obtained in this manner.At the time of cesarean section, the level of maternal serum rotavirus IgG rangedbetween 300 and 5,600 U/ml, where the limit of detection was 5 U/ml. The firstgroup contained five animals that were monitored for up to 7 months of age forevidence of a natural rotavirus infection based on increases in their titers ofserum rotavirus IgG or IgA between blood collections. The second group (eightanimals) were bled at the time of birth and just before the time of rotaviruschallenge, and rotavirus IgG and IgA levels in these serum specimens weremeasured. Between 14 and 42 days after birth, these animals were transferred toa separate room in the facility and intragastrically challenged with 3 � 104

focus-forming units (FFU) of our new wild-type strain of macaque rotavirusfollowing administration of 2 ml of 4% sodium bicarbonate to buffer stomachacidity. Stool specimens were collected between one and four times each day forthe next 14 days, and the levels of rotavirus shedding were quantified. In addi-tion, the consistencies of these stool specimens were graded for detection ofdiarrhea. During this period, the macaques were evaluated each day for signs oflethargy as an additional indicator of illness.

Quantitation of rotavirus IgG and IgA in serum specimens. The levels ofrotavirus IgG and IgA were determined in serum specimens by enzyme-linkedimmunosorbent assays (ELISA) essentially as described previously (1, 46). Inbrief, 96-well microtiter plates were coated with purified, double-layered simianrotavirus SA11 or with mock-infected lysate purified in an identical fashion. Thiswas followed by the stepwise addition of diluted specimen or control sera,biotinylated goat anti-monkey (rhesus) IgG (Research Diagnostics, Inc., Flan-dus, N.J.), peroxidase-conjugated avidin-biotin (Vector Laboratories, Inc., Bur-lingame, Calif.), and substrate (orthophenylenediamine [Sigma Aldrich, St.Louis, Mo.]). Optical density (OD) values were determined at 490 nm. The levelswere then expressed as units of IgG per milliliter, based on a standard curvegenerated from a human serum pool arbitrarily assigned a level of 1,000 U/ml.The lower limit determinable by this assay under the conditions used was 5 U/ml.Rotavirus IgA was measured in the same manner, except that biotinylated goatanti-monkey IgA (Research Diagnostics, Inc.) was used. In this case, the controlserum (human pool) was assigned a value of 250 U/ml, and the lower limitmeasurable was 10 U/ml.

Detection and quantitation of rotavirus antigen in stools of macaques. Frozenstools collected from the cages of individually housed macaques were thawed,

made into 20% (wt/vol) suspensions with Earle’s balanced salt solution (EBSS),and tested for the presence of rotavirus antigen by ELISA as described elsewhere(30, 46). For the group of conventional animals, shedding was quantified asoptical density units (A490), and the highest OD value measurable in the rota-virus-positive specimens was 3.0. Therefore, the quantity of rotavirus antigenpresent in these specimens was expressed as OD measurements up to 3.0. Forcesarean section-derived macaques inoculated with the new strain of wild-typemacaque rotavirus, fecal shedding of rotavirus antigen was quantified by ELISAas nanograms per milliliter of 20% suspensions of stool, based on a standardcurve generated by using purified double-layered particles of murine rotavirusstrain EDIM.

Quantitation of infectious rotavirus in stool specimens. Rotaviruses present in20% suspensions of macaque stools were quantified by a fluorescent-focus assay(47). Titers are expressed as FFU per milliliter of the 20% stool suspensions.

Cell culture adaptation of rotavirus from macaque stools. Rotaviruses in stoolwere adapted to grow in MA104 (monkey kidney) cells by using methods similarto those previously reported (30). In brief, 20% (wt/vol) stool suspensions anddilutions of these samples (in EBSS) were treated with trypsin (15 �g/ml;GIBCO Laboratories, Grand Island, N.Y.) (1:250) to activate the virus. Follow-ing centrifugation (1,200 � g, 20 min) to remove debris, the supernatants wereadded to tube cultures containing monolayers of MA104 cells. After adsorption(2 h) on a roller apparatus, the cultures were washed and medium without serum,but with trypsin, was added. The culture tubes were rolled for 4 days or untilcytopathic effects reached 3� (whichever came first) and then were stored at�20°C. Subsequent passages were conducted without trypsin pretreatment of thelysate from the previous passage. In this study, the presence and quantity ofrotavirus were determined after two passages in MA104 cells, using the sameELISA procedure as described for detection of rotavirus in stool specimens.

Electrophoretic analysis of viral RNA segments. The double-stranded RNAgenome segments of passage 2 of the culture-adapted macaque rotaviruses wereextracted from viral lysates and analyzed by polyacrylamide gel electrophoresis(50). The electropherotype of one of the isolates was compared to those ofprototype simian rotaviruses RRV and SA11, also grown in MA104 cells.

G serotyping of the culture-adapted macaque rotaviruses. The G serotypes ofpassage 2 of the culture-adapted macaque rotaviruses were determined by anELISA with prototype G1 to G4 (Wa, DS-1, P, and ST3, respectively) humanrotavirus strains as controls (15, 49). VP7-specific monoclonal antibodies(MAbs) against G1 (MAb 5E8), G2 (MAb 1C10), G3 (MAb 159), and G4 (MAbST3:1) rotavirus strains were used to coat 96-well microtiter plates (captureantibodies), and hyperimmune guinea pig antisera against G1 to G4 prototypehuman rotaviruses were used as the detector antibodies. The MAbs against G1to G3 strains were gifts of H. B. Greenberg (Stanford University, Palo Alto,Calif.) and the ST3:1 MAb was a gift of B. Coulson (University of Melbourne,Melbourne, Australia).

Subgroup analysis of the culture-adapted macaque rotaviruses. Subgroupdetermination of passage 2 of the culture adapted macaque rotaviruses wasperformed by an ELISA with subgroup-specific MAbs 225/60 (subgroup 1) and631/9 (subgroup 2) (15, 29, 50, 52). Both MAbs were gifts of H. B. Greenberg.Control rotaviruses included in this assay were the simian RRV (subgroup 1[SG1]) and human Wa (SG2) strains. Both control rotaviruses reacted only withtheir respective subgroup-specific MAb.

Nucleotide sequencing of the VP4 and VP6 genes of the TUCH strain ofmacaque rotavirus. Double-stranded cDNAs of genes 4 and 6 of CsCl gradient-purified, culture-adapted rotavirus (passage 3) obtained from the stool of ma-caque EA40 (specimen date, 2 January 2003), subsequently named the TUCHstrain, were generated by reverse transcription-PCRs (RT-PCR) with theThermo Script RT-PCR system (Invitrogen/Life Technologies, Carlsbad, Calif.)and Vent DNA polymerase (New England BioLabs, Beverly, Mass.). Briefly, RTwas performed with 1 �g of purified double-stranded genomic RNA in 25 �l ofdistilled water containing an RNase inhibitor (20 U of RNaseOut [InvitrogenLife Technologies]) and a 200 nM concentration of a forward primer (gene 4,5�-GGC TAT AAA ATG GCT TCG CTC-3� [corresponding to nucleotides 1 to21]; gene 6, 5�-GGC TTT TAA ACG AAG TCT TC-3� [corresponding tonucleotides 1 to 20]) and a reverse primer (gene 4, 5�-GGT CAC ATC CTCTAG AAA TTA C-3� [corresponding to nucleotides 2342 to 2362]; gene 6,5�-GGT CAC ATC CTC TCA CTA CGG CAT TC-3� [corresponding to nucle-otides 1331 to 1356]) designed from the noncoding regions of the simian SA11rotavirus genes. The reaction mixture was denatured (3 min, 94°C), and theprimers were allowed to rapidly anneal to viral RNA by cooling the suspensionon ice. Next, 4.0 �l of 5� cDNA synthesis buffer (Invitrogen Life Technologies),1.0 �l of 0.1 M dithiothreitol, 1.0 �l of RNaseOut (40 U/�l), 1.0 �l of diethylpyrocarbonate-treated water, and 1.0 �l of ThermoScript reverse transcriptase(15 U/�l) were added to the reaction mixture on ice. Reverse transcription was

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carried out at 50°C for 60 min in a heating block. The reaction was terminatedby transferring the reaction mixture in a heating block set at 85°C for 5 min. Thereaction mixture was cooled, 2 U of RNase H in 1 �l was added, and the reactionmixture was incubated at 37°C for 20 min. PCR was carried out in a 50-�l volumecontaining 2.0 �l of the RT-PCR products, 5 �l of 10� amplification buffer, 1.5�l of 10 mM deoxynucleoside triphosphates, 1.0 �l of 50 mM MgSO4, 1.5 �l offorward and 1.5 �l of reverse primer (200 nM each), and 2.5 U of Platinum PfxDNA polymerase (Invitrogen Life Technologies). The template was denatured(94°C, 2 min), and then 30 cycles of PCR were carried out. Each PCR cycleconsisted of a denaturation step (94°C for 30 s), an annealing step (55°C for 30 s),and an extension step (68°C for 3 min for gene 4 and for 2 min for gene 6). Afterthe PCR cycle, an additional incubation step was carried out (72°C, 7 min). PCRproducts were purified by using the QIAquick PCR purification kit (Qiagen Inc.,Valencia, Calif.). The nucleotide sequences of the VP4 and VP6 genes weredetermined by using purified double-stranded cDNAs generated by RT-PCR astemplates. Sequencing was performed by Cleveland Genomics (Cleveland,Ohio), using an ABI DNA sequencer (Applied Biosystems, Foster City, Calif.).The primer pair used for generating double-stranded DNA was also used tosequence the initial 500 nucleotides from the ends of the positive and thenegative cDNA strands. New primer pairs were designed by using the sequencegenerated until cDNA strands were completely sequenced. The gene sequencewas determined twice with PCR products generated in separate reactions, usingboth strands as templates.

Phylogenetic relationship of TUCH rotavirus VP4 and VP6 gene sequenceswith those of other rotavirus strains. CLUSTALW (http://www.ebi.ac.uk/clustalw/), a program that is commonly used for phylogeny reconstruction, wasemployed to analyze phylogenetic relationships of the deduced complete aminoacid sequences of the TUCH VP4 and VP6 proteins with those of cognateproteins of other rotaviruses. This program predicts phylogenetic trees by com-paring alignment scores for all possible pairs of the rotavirus VP4 and VP6sequences. The rotavirus gene sequences used for pairwise alignment were firstretrieved from protein databases by using WU-BLAST2 (http://BLAST.wus-tl.edu). The sequences were then aligned by using CLUSTALW to search forregions of similarity among the sequences. The fundamental unit algorithmoutput of BLAST is the high-scoring segment pair, which consists of two se-quence fragments of arbitrary but equal length whose alignment is locally max-imal and for which the alignment score meets or exceeds a threshold (the defaultcutoff score was chosen). In the analyses performed here, the default Blosum62was used for the scoring matrix. Unrooted phylogenetic trees were constructedby using the neighbor-joining method (38). The trees are displayed with Tree-View (34).

Preparation of a challenge pool of unpassaged TUCH rotavirus. To prepare apool of unpassaged simian rotavirus to be used for subsequent challenge studies,the stool obtained on 2 January 2003 from macaque EA40 was processed.Although the rotaviruses from all five macaques examined had identical electro-pherotypes and therefore were likely to be very similar strains, only the rotavirusin this one stool specimen has been given the designation TUCH, and only thisvirus was used in subsequent experiments under that designation. This stool wasused because only it and one other, of the seven stools examined, contained ahigh titer of infectious rotavirus, and it had the larger quantity of the two. A 5%(wt/vol) suspension of this entire stool (3.2 g) was made in EBSS by shaking (2h, 4°C) with glass bends on an automated shaker. After centrifugation (1,200 �g, 20 min, 4°C) to clarify the suspension, the supernatant was filtered (0.2-�m-pore-size filter) and stored (�70°C) in 1-ml aliquots. The titer of the original 5%suspension was 3.4 � 105 FFU/ml, while the frozen aliquots contained 3.0 � 104

FFU/ml (9% recovery).Nucleotide sequence accession numbers. The GenBank accession numbers for

the TUCH VP4 and VP6 protein genes are AY596189 and AY594670, respec-tively.

RESULTS

Isolation of rotavirus from naturally infected rhesus ma-caques. (i) Identification of juvenile macaques with no evi-dence of previous rotavirus infection. Before attempting toobtain rotavirus from naturally infected rhesus macaqueshoused within open cages in containment rooms at theTNPRC, it was first necessary to demonstrate that rotavirus isendemic in this macaque population. For this, we relied onserum rotavirus IgG measurements. Upon examination of a

group of 16 juvenile macaques age 2.6 to 5.9 months andhoused within the facility, it was noted that 5 had high titers ofrotavirus IgG (geometric mean titer, 704 U/ml) and that theother 11 had much lower levels (geometric mean titer, 13U/ml) (Table 1). Because the average ages of the two groups ofmacaques were comparable (5.2 versus 5.0 months), it wasassumed that at least the five animals with high titers of rota-virus IgG had experienced at least one natural rotavirus infec-tion. It is likely that rotavirus IgG detected in the other 11macaques was residual transplacental antibody. These sugges-tions were supported by the finding that the 5 macaques withthe highest levels of rotavirus IgG had detectable quantities ofserum rotavirus IgA, while only 1 of the 11 macaques with littleor no detectable rotavirus IgG had detectable rotavirus IgA(Table 1). These results established that rotavirus infectionswere, indeed, endemic within this facility. They also identifiedanimals that had no evidence of a previous rotavirus infectionbased on their low titers of rotavirus IgG and, therefore, thatmay be more susceptible to a natural infection within thefollowing weeks.

(ii) Detection of rotavirus in stools of naturally infectedmacaques. To obtain rotavirus from naturally infected ma-caques, stool specimens were collected two times each weekfrom the 10 macaques with the lowest titers of serum rotavirusIgG, and with undetectable rotavirus IgA, for a period of 10weeks beginning 13 days after they were initially screened (12November 2002) for rotavirus antibody. Blood specimens werealso collected monthly over a 27-week period to detect changesin serum rotavirus IgG titers. Rotavirus antigen was detectedin 6 of the 10 macaques in at least one stool specimen (Table2). Corresponding increases in rotavirus IgG titers were de-tected in every case. No gastrointestinal illness (vomiting ordiarrhea) was observed in any animal in association with rota-virus detection.

In every animal in which rotavirus was detected, the quantityshed was sufficiently large so that the optical density deter-mined by ELISA was off the scale (�3.0) in at least onespecimen (Table 2). To determine the recoveries of live rota-virus in these stools, the titers of infectious virus in the speci-

TABLE 1. Serum rotavirus IgG and IgA titers in juvenile macaqueshoused within containment rooms at the TNPRC

Macaque Locationa Age(mos)

RotavirusIgG (U/ml)

RotavirusIgA (U/ml)

DV13 C/E04 5.9 889 47DV67 C/E07 5.6 25 �10EA30 C/E04 5.4 1142 64EA17 C/E05 5.3 14 �10EB06 C/E04 5.2 91 13EB17 C/E06 5.2 52 �10EA40 C/E06 5.1 �5 �10EA42 C/E07 5.1 �5 �10EB25 C/E04 5.1 391 34EB31 C/E04 5.1 475 33EC67 C/E06 4.7 9 �10EB57 H/109 4.4 �5 �10EB58 C110 4.4 739 35EB64 C110 4.4 18 �10EE01 H/109 3.0 7 �10ED29 C/E06 2.6 14 �10

a The first letter designates the building, and the number designates the room.

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mens with the highest optical densities obtained from the firstfive animals that shed rotavirus were measured by a fluores-cent-focus assay. Based on the numbers of focus-forming unitsper milliliter of stool suspension (20%, wt/vol), these titersvaried widely, and only two specimens had titers of �106

FFU/ml (Table 2). Differences in titers between specimenswere probably due primarily to differences in specimen con-servation, since the stools were obtained in various stages ofdryness from the bottoms of the cages.

Characterization of rotaviruses obtained from stool speci-mens of naturally infected macaques. (i) Electropherotypes ofculture-adapted rotaviruses. Eight stool specimens from fivemacaques for which the titers of infectious rotavirus were de-termined were also processed and used to infect MA104 cellsin an attempt to culture adapt the rotaviruses in these speci-mens. A complete (4�) cytopathic effect was observed within48 h in all culture tubes inoculated with the rotavirus-positivestool preparations, and, when evaluated for the presence ofrotavirus by ELISA after two cell culture passages, all eighttissue culture lysates contained large quantities of virus (i.e., allhad optical densities of �3.0, even the lysate obtained from the

specimen with an infectivity titer of �2.8 � 102 FFU/ml). Thus,rotaviruses in these specimens required no adaptation to growin cell culture.

When the double-stranded RNA genomes of these eightculture-adapted isolates (passage 2) were analyzed by poly-acrylamide gel electrophoresis, all had identical electrophero-types (Fig. 1A). In addition, the electropherotype of a repre-sentative of the group (macaque EA40) was compared to thoseof simian rotaviruses SA11 and RRV, and all three electro-pherotypes were found to be distinctly different (Fig. 1B).

(ii) VP7 serotypes and VP6 subgroups of the culture-adapted rotaviruses obtained from macaques. The VP7 or Gserotype of simian rotaviruses previously characterized hasbeen found to be G3 (11). We utilized serotype-specific G1 toG4 monoclonal antibodies against VP7 in an ELISA format inan attempt to determine the G type of rotaviruses in the eightculture-adapted preparations (passage 2) and found that alleight reacted strongly and specifically with the G3 MAb 159(results not shown).

The intermediate capsid layer of the rotavirus particle iscomposed of the VP6 protein, the group antigen (8). Within

TABLE 2. Recovery of rotavirus from naturally infected juvenile macaques housed at the TNPRCa

Macaque Location Age at enrollment(mo)b

Date of stool collection(day-mo-yr)c ELISA OD Titer of virusd

Date of bloodcollection

(day-mo-yr)

Rotavirus IgG(U/ml)

DV67 C/E07 5.6 13-1-03 �3.0 1.4 � 103 12-11-02 2516-1-03 �3.0 14-1-03 50

10-2-03 64424-3-03 39

EA17 C/E05 5.3 30-12-02 �3.0 6.2 � 103 12-11-02 1414-1-03 1,36710-2-03 27424-3-03 5025-4-03 115

EA40 C/E06 5.1 30-12-02 �3.0 8.1 � 103 12-11-02 �52-1-03 2.8 2.7 � 106 14-1-03 6386-1-03 1.6 10-2-03 2,957

24-3-03 1,906

EA42 C/E07 5.1 16-12-02 2.4 12-11-02 �519-12-02 �3.0 7.0 � 106 14-1-03 �5,00023-12-02 �3.0 �2.8 � 102 10-2-03 �5,0009-1-03 1.0 24-3-03 �5,000

EB64 C110 4.4 19-12-02 �3.0 1.2 � 104 12-11-02 189-1-03 1.2 14-1-03 672

10-2-03 29324-3-03 7725-4-03 200

ED29 C/E06 2.6 23-1-03 �3.0 12-11-02 1427-1-03 2.5 14-1-03 �530-1-03 1.9 10-2-03 799

24-3-03 45025-4-03 1,0383-6-03 252

a Stool samples were collected twice weekly from 10 juvenile macaques found to have very low titers of serum rotavirus IgG. These were tested for rotavirus antigenby ELISA, and those that were positive, along with the date that the specimen was collected and the OD determined by ELISA, are included here. Locations are asdescribed for Table 1. Titers in the seven stools with the highest OD were determined by a fluorescent-focus assay to detect infectious rotavirus. Blood specimens werecollected monthly, and serum rotavirus IgG titers were determined for these specimens.

b The enrollment date was 12 November 2002.c Stool collections were initiated on 25 November 2002 and terminated on 6 February 2002.d Titers are expressed as FFU per milliliter in 20% (wt/vol) stool suspensions.

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group A rotaviruses, four subgroups have been identifiedbased on their reactivities with subgroup-specific MAbs thatrecognize epitopes within the VP6 protein (13, 15, 24, 25, 43).These include SG1, SG2, SG1/SG2, and non-SG1/SG2. It hasalso been reported that animal rotaviruses typically belong toSG1. In contrast, most human rotaviruses belong to SG2. In anELISA format, passage 2 of the culture-adapted rotavirusesobtained from macaques reacted strongly with MAb 225/60 toSG1 and had no reaction with the SG2 MAb 631/9 (results notshown).

Based on these results, the rotaviruses obtained from ma-caques in this study were classified as serotype G3 and sub-group 1, as has been found for previously characterized simianrotavirus strains. The rotaviruses isolated from all five ma-caques characterized in this study appeared to be similar if notidentical. However, in order to maintain consistency, all fur-ther studies were conducted with virus obtained from onespecimen of one macaque, i.e., EA40. The virus obtained fromthis animal was named TUCH for Tulane University and Cin-cinnati Children’s Hospital.

(iii) Phylogenetic analysis of its VP4 protein indicates thatTUCH belongs to a new P genotype. Although the serotype andsubgroup of the macaque rotavirus were found to be typical ofsimian rotaviruses and its electropherotype clearly distin-guished it from prototype simian rotavirus strains SA11 andRRV, it was still unclear whether TUCH was a previouslyunidentified rotavirus strain. To ensure that it is distinct fromthe other rotavirus strains, nucleotide sequence analysis of theVP4 gene of a culture-grown isolate (three passages) frommacaque EA40 was performed, and the deduced amino acidsequence was compared to those of representatives of the 22

established P genotypes by phylogenetic analyses (11, 28, 37).The greatest amino acid homologies between macaque rotavi-rus and the other VP4 proteins were with representative P[3]rotaviruses, which included the simian RRV strain (Table 3).Homologies with these strains (85.3 to 86.2%) were, however,very similar to those found with the P[10] 69 M human strain(85.4%) and the P[2] SA11 simian strain (84.4%). VP4 pro-teins of representatives of six other genotypes also showed�80% homology with the macaque rotavirus VP4, suggestingthat the point of divergence from the macaque VP4 proteinmay have been similar for many rotavirus strains.

To further examine this possibility, phylogenetic analysis ofthe VP4 proteins of the TUCH macaque rotavirus and repre-sentatives of the 22 previously established P types was per-formed, followed by the construction of a phylogenetic tree(Fig. 2). From this analysis it appears that the TUCH VP4 genediverged from those of other genotypes at a distant point intime. This, coupled with the fact that none of these represen-tative strains share �89% amino acid homology with the VP4protein of the new macaque rotavirus (the suggested require-ment for inclusion within the same VP4 genotype [14]), indi-cates that the TUCH strain belongs to a new P genotype, whichwe tentatively classify as P[23]).

(iv) The gene encoding TUCH VP6 also diverges from VP6genes of other rotavirus strains. The VP6 protein or groupantigen is highly conserved, especially within group A mam-malian rotaviruses (48). However, because of the divergenceidentified between the VP4 genes of TUCH and other rotavi-rus strains, it was of interest to determine whether this alsooccurred with another TUCH gene by using phylogenetic anal-ysis. The greatest amino acid homology between TUCH VP6

FIG. 1. Electrophoretic patterns of the double-stranded RNA ge-nome segments obtained either from passage 2 of the culture-adaptedmacaque rotaviruses (A) or a representative of this group of viruses(no. 6) analyzed together with RNAs obtained from prototype simianrotaviruses RRV and SA11 (B). Rotavirus sample designations: 1:macaque EA42 (19 December 2002); 2: macaque EA42 (23 December2002); 3: macaque DV67 (13 January 2003); 4: macaque EA17 (30December 2002); 5: macaque EA40 (30 December 2002); 6: macaqueEA40 (2 January 2003); 7: macaque EB64 (19 December 2002); 8:macaque EB64 (9 January 2003).

TABLE 3. Comparison of amino acid identities of the TUCH VP4protein with those of rotaviruses representative of all 22 known

P genotypes

Rotavirus strain P genotype % Identitywith TUCH

GenBankaccession no.

NCDV (bovine) 1 74.6 C31159SA11 (simian) 2 84.4 D16347RRV (simian) 3 86.2 M18736HCR3 (human) 3 85.3 L19712K9 (canine) 3 86.2 D14725DS1 (human) 4 71.9 P11196UK (bovine) 5 76.7 P12474Gottfried (porcine) 6 74.7 M38516OSU (porcine) 7 80.2 X13190KU (human) 8 72.4 M21014K8 (human) 9 68.7 D9026069M (human) 10 85.4 M60600KK3 (bovine) 11 81.6 D13393F123 (equine) 12 82.5 D16342MDR13 (porcine) 13 80.7 L07887Mc35 (human) 14 69.6 D14032LP14 (ovine) 15 83.4 L11599EDIM (murine) 16 75.3 AF03949993/83 (bovine) 17 61.9 Q08010L338 (equine) 18 79.6 D13399Mc345 (human) 19 76.4 D38054EHP (murine) 20 82.9 U08424Hg18 (bovine) 21 78.4 AF237665160/01 (lapine)a 22 66.1 AF526374

a VP8 portion of the VP4 protein only (295 amino acids).

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and that of another rotavirus VP6 protein deduced from nu-cleotide sequence analysis was determined to be 95.5% (Table4). This degree of homology, however, is the same or verysimilar to that shared with VP6 proteins of multiple rotavirusstrains, again suggesting that the TUCH strain diverged fromother rotaviruses at a distant point in time. A phylogenetic treeconstructed from the amino acid sequences of these VP6 pro-teins indicates that the TUCH VP6 gene, like the VP4 gene ofthe virus, has diverged from all other rotavirus strains exam-ined (Fig. 3).

Inoculation of young macaques with the wild-type TUCHstrain to establish a nonhuman primate model for studies onactive immunity. (i) Cesarean section-derived macaques canbe maintained rotavirus free within the TNPRC. Because ro-tavirus was found to be endemic within the TNPRC, beforeconducting a rotavirus challenge study it was important todemonstrate that macaques housed in the TNPRC could bemaintained without experiencing a natural rotavirus infection.It was already demonstrated that animals housed within con-ventional rooms within this facility became naturally exposedto rotavirus and that the TUCH strain was derived from one ofthese animals. To determine whether newborn macaques couldbe kept rotavirus free if derived and maintained in the absenceof older animals, a group of five macaques was obtained bycesarean section and monitored until the ages of between 3.5

FIG. 2. Phylogenetic analyses of VP4 proteins of the TUCH rotavirus strain and other strains of rotavirus representative of the 22 reported Pgenotypes. Phylogenetic trees of the VP4 proteins were constructed as described in Materials and Methods. The line lengths in the trees indicatethe number of nucleotide differences per site present in the sequences, and the scale represents 0.1 change per site.

TABLE 4. Comparison of amino acid identities of the TUCH VP6protein with VP6 proteins of representative mammalian and avian

group A rotaviruses

Rotavirus strain % Identitywith TUCH

GenBankaccession no.

UK (bovine) 95.5 P18610WC3 (bovine) 95.5 Q8JT15LP14 (ovine) 95.5 Q8621922R (bovine) 95.2 Q9DUD7NCDV (bovine) 95.2 Q91N57RRV (simian)a 94.5SA11 (simian) 94.0 P03531S2 (human) 94.0 P08035H-2 (equine) 94.0 P16488Eb1M (murine) 93.5 Q98347B223 (bovine) 93.5 Q91N56L338 (equine) 92.7 Q86347CJN (human) 92.4 Q8JT22Gottfried (porcine) 92.2 P16593Wa (human) 91.9 P03530RV3 (human) 91.7 Q82120OSU (porcine) 90.7 Q91N61YM (porcine) 89.9 Q06386CRW-8 (porcine) 89.9 P89043Ty-1 (avian) 72.8 Q86341993/83 (bovine) 72.5 Q8JXK7Ch-1 (avian) 71.5 Q86351

a E. Mackow (State University of New York, Stony Brook), personal commu-nication.

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and 7 months for evidence of natural rotavirus infection basedupon increases in serum rotavirus antibody levels. All animalsexperienced a steady decline in both serum rotavirus IgG andIgA from the date of birth (cord blood) until the end of theobservation period (Table 5), thus suggesting that macaquescould be maintained rotavirus free within the TNPRC if de-rived and raised under these conditions.

(ii) Inoculation of young, rotavirus-naive rhesus macaqueswith the TUCH strain. A 5% suspension of stool from ma-caque EA40 was filtered and stored frozen in 1-ml aliquots.The titer of this preparation was 3 � 104 FFU/ml, and 1 ml wasgiven intragastrically to each of eight cesarean section-derivedrhesus macaques between 14 and 42 days of age following

intragastric administration of 2 ml of 4% sodium bicarbonate.The titers of serum rotavirus IgG on the day of challengevaried from animal to animal, but all had declined from thetiters found on the day of birth (Table 6). Soft stools weredetected during some collections in several animals during the14 days after challenge, but none were indicative of diarrhea.Furthermore, the behavior of all macaques remained normalduring this period, without evidence of lethargy. All eight ma-caques shed large quantities of rotavirus in their stools, begin-ning between 1 and 5 days after challenge and declining toundetectable or nearly undetectable levels by the end of the14-day observation period (Fig. 4). Even so, only three of theeight inoculated animals had detectable increases in serum

FIG. 3. Phylogenetic analyses of VP6 proteins of the TUCH rotavirus strain and other strains representative of mammalian and avian groupA rotaviruses from different species. Phylogenetic trees of the VP6 proteins were constructed as described in Materials and Methods. The linelengths in the trees indicate the number of nucleotide differences per site present in the sequences, and the scale represents 0.1 change per site.

TABLE 5. Serum rotavirus IgG and IgA levels in cord blood andserum samples obtained over time from five cesarean section-

derived rhesus macaques housed within the TNPRCa

Macaque DOBc

Rotavirus IgGb Rotavirus IgAb

Cordblood

Venous blood Cordblood

Venous blood

7/17/02 9/11/02 7/17/02 9/11/02

EA13 5/29/02 393 73 8 53 �10 �10DV88 5/23/02 947 118 13 55 �10 �10DV42 5/14/02 2,343 155 17 63 13 10DR09 4/18/02 380 �5 �5 48 �10 �10DN08 2/7/02 603 �5 �5 25 �10 �10

a Caesarean section-derived macaques were housed in a room containing noother animals. Cord blood was collected on the day of birth, and venous bloodspecimens were collected on the specified dates (month/day/year).

b Serum rotavirus IgG and IgA levels expressed in units per milliliter.c DOB, date of birth (month/day/year).

TABLE 6. Serum rotavirus IgG levels in eight rhesus macaquesinoculated with the TUCH strain as determined on their day ofbirth, on the day of inoculation, and 1 month after inoculation

MacaqueAge at

inoculation(days)

Rotavirus IgGa

Day ofbirth

Day ofinoculation

1 mo afterinoculation

EH73 42 1,958 110 56EH84 42 1,352 6 40FB82 28 278 150 1,776FB83 28 612 274 294FB88 26 5,510 2,082 616FB91 21 3,472 1,724 719FB97 18 1,779 1,265 312FC06 14 1,164 832 510

a Serum rotavirus IgG levels in units per milliliter.

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rotavirus IgG titer by 1 month after inoculation (Table 6),possibly due, at least in part, to maternal antibody.

DISCUSSION

Since nonhuman primates are the animals most related tohumans, it follows that they should be the most reliable formodel studies using human disease agents. Accordingly, manystudies on the pathogenesis of and immunity to such agentshave been performed with nonhuman primates. Very few stud-ies, however, have been conducted with rotavirus in any non-human primate species (21, 23, 26, 31, 36, 41, 55). A majorlimitation for performing such studies has been the absence ofa challenge strain of simian rotavirus that will consistentlyresult in productive infections in a nonhuman primate speciesafter oral challenge. The only simian rotaviruses in use todayare the SA11 strain, reported by Malherbe and Harwin in 1963(27), and the RRV strain, discovered by Stuker et al. in 1980(42). Both have been passaged numerous times in cell culture,a method commonly used for viral attenuation, and no unpas-saged (wild-type) simian rotavirus is presently available. Thefirst purpose of this study was to obtain and characterize sucha virus and prepare a challenge pool for use in a nonhumanprimate model for rotavirus.

Although rotaviruses are not entirely species specific (19,32), the vast majority of natural isolates obtained from anyspecies, including humans, have been associated specifically

with that species. Since the nonhuman primates most com-monly used as experimental models are macaques, the goal wasto obtain a challenge rotavirus strain that is endemic in ma-caques and fully adapted to infect this specific nonhuman pri-mate. Therefore, we first determined whether rotavirus wasendemic in rhesus macaques housed at the TNPRC. Based onthe presence of high titers of serum rotavirus IgG in all ma-caques �1 year of age (15 total), rotavirus is clearly endemic inmacaques in this colony.

Next, we identified rhesus macaques within this colony thatwere the most likely to experience a rotavirus infection duringthe following months. Even though repeat rotavirus infectionsare common in humans (2) and are likely to also occur inmacaques, the most severe rotavirus disease in humans almostinvariably occurs after their first infection (44), provided thatthis infection takes place during the period of greatest suscep-tibility, when a child is 6 months of age or older (22). Our plan,therefore, was to identify rhesus macaques of approximatelythis equivalent age that had no evidence of a previous rotavirusinfection based on serum rotavirus antibody levels. Accord-ingly, a group of 16 macaques age 2.6 to 5.9 months wereevaluated for the presence of serum rotavirus IgG and IgA,and based on the absence of serum rotavirus IgA and very lowlevels of serum rotavirus IgG in 10 of these animals, these wereconsidered to be the most likely to be susceptible to a rotavirusinfection. Stool specimens were collected over a 10-week pe-

FIG. 4. Fecal shedding of rotavirus antigen after TUCH inoculation of eight rhesus macaques age 14 to 42 days. On days when �1 stoolspecimen was collected, the mean quantity of rotavirus antigen shed in the collected specimens was determined. Levels of antigen shed areexpressed as nanograms of rotavirus protein per milliliter in 20% stool suspensions. The ages of the macaques on their day of inoculation arespecified in Table 6. Shedding data for macaques FB82, FB88, and FB97 were already provided in tabular form in a very recent publication (39).

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riod from these animals, and six shed rotavirus. Although moststools had relatively low titers of infectious rotavirus, probablydue to viral inactivation prior to stool collection, one specimeneach obtained from two of the animals (EA40 and EA42)contained titers of �106 FFU/ml, sufficient to utilize for theproduction of a challenge pool of unpassaged rotavirus.

The rotaviruses obtained from naturally infected macaqueswere then characterized. First it was shown that they were fullyadapted to grow in cell culture and produced a complete cy-topathic effect in MA104 cells during their first passage. Thisproperty is typical of some animal rotavirus strains and sharplycontrasts with results found with human rotaviruses, wheremultiple cell culture passages are required to develop thisphenotypic trait (50). The culture-grown rotaviruses obtainedfrom macaques all had identical electropherotypes which weredistinct from those of SA11 and RRV. However, these viruseswere identified as serotype G3 and subgroup 1, both featurescharacteristic of simian rotaviruses (22). Furthermore, a partialsequence comparison (amino acids 51 to 206) between the VP7protein of one of the new macaque rotaviruses and the VP7proteins of RRV and SA11 revealed that they shared 94.9 and95.6% homology, respectively (results not shown), supportingthe indication that the new macaque rotaviruses belong toserotype G3.

Because viruses obtained from all macaques were similar ifnot identical, the rotavirus obtained from only one specimenfrom one macaque (EA40) was utilized as the representative ofthe new rotavirus strain, which was named TUCH. Nucleotideanalysis of the complete coding sequence of the VP4 gene fromthe TUCH strain revealed that it is genotypically dissimilar tothose from rotaviruses belonging to the 22 established P types(11, 28, 37). Rotaviruses have been classified within the same Ptype if they share �89% homology (14). No rotavirus belong-ing to any established P type was found to share �86.2%homology with the VP4 protein of TUCH. The suggestion thatthe TUCH VP4 gene has evolved from those of other rotavi-ruses was supported by phylogenetic analysis. Therefore, theTUCH strain was tentatively classified as genotype P[23].

Because the VP4 gene of TUCH appeared to have greatlydiverged from VP4 genes found in other rotavirus strains, itwas of interest to determine whether this could also be dem-onstrated for another TUCH gene. For this we selected theVP6 gene, which is highly conserved among group A rotavi-ruses (22). Although the degree of difference between theTUCH VP6 protein and those of numerous others to which itwas compared is much less than found for the VP4 proteins,the greatest homology was still only 95.5%. Furthermore, phy-logenetic analysis of TUCH VP6 supported the hypothesis thatthe gene encoding this protein has also substantially divergedfrom cognate genes of other rotavirus strains. Therefore, al-though TUCH has retained epitopes required for retention ofthe VP7 serotype G3 and VP6 subgroup 1 specificities typicalof simian rotaviruses, it is quite dissimilar to the standardsimian rotavirus strains that are in use in many laboratoriesworldwide today. In fact, based on phylogenetic analysis withthe VP4 and VP6 genes, TUCH is more closely related tomouse strains than it is to the simian SA11 or RRV strain.Possibly the TUCH strain arose from a reassortment eventbetween a simian rotavirus and a rotavirus from another spe-cies at some distant point in time. If so, some genes, such as

those for VP6 and VP4, may have been derived from thenonsimian strain. Independent segregation of rotavirus geneshas been described in numerous publications, and even manyhuman strains have been identified as reassortants betweenanimal and human rotaviruses (see, e.g., reference 20). How-ever, it is also possible that TUCH arose from a commonancestor of both simian and other G3 strains. Sequence com-parisons between other gene segments of the TUCH strain andthose from multiple rotaviruses could provide a more definitiveexplanation of the origin of the TUCH virus.

The second purpose of this study was to determine whetheran unpassaged preparation of TUCH would replicate in pre-viously uninfected macaques, resulting in consistently high lev-els of fecal rotavirus shedding and, possibly, diarrheal disease.Based on this study with eight cesarean section-derived ma-caques age 14 to 42 days, several of which contained high levelsof maternal (transplacental) rotavirus IgG on their date ofinoculation, the TUCH strain appears to be excellent formodel studies on rotavirus immunity in macaques. In the agerange examined, which is within a window sufficient to immu-nize and challenge, all eight animals consistently shed largequantities of rotavirus antigen. Presumably this age rangecould be readily extended, since the TUCH strain itself wasderived from an animal that was �6 months of age. As wasfound with the mouse model that we established over a decadeago for studies on rotavirus vaccines and their mechanisms ofprotection (51), the TUCH strain will be useful for studies onboth active and passive immunity. However, as was also foundwith rodent and rabbit models for rotavirus in their homolo-gous hosts (6–10, 16, 51), the TUCH strain will not be usefulfor studies on active immunity against diarrheal disease inmacaques. In place of this, fecal shedding of the TUCH viruscan be used as a marker of rotavirus infection in macaques, ashas been used extensively in mice and rabbits.

ACKNOWLEDGMENTS

This study was supported by NIAID grant AI056847-01 to A.H.-C.C.and by a Cincinnati Children’s Hospital Medical Center pilot grant toR.L.W. Partial support was provided by TNPRC base grant RR00164.

ADDENDUM

After this work was completed, we became aware of a pub-lication (24a) that describes a porcine group A rotavirus (strainA34) belonging to a potential new P genotype based on se-quence analysis of part (amino acids 13 to 250) of the VP8region of the VP4 gene of this virus (GenBank accession no.AY174094). This region of the VP4 protein of the A34 strainwas found to share 79.8% homology with the cognate region ofthe TUCH VP4 protein, thus confirming that the P type of theA34 strain is distinct from that of TUCH. If upon analysis ofthe complete sequence of the VP4 gene of the A34 strain, it isconfirmed to belong to a new P genotype, the TUCH strainwould then be tentatively classified as P[24] rather than P[23].

REFERENCES

1. Bernstein, D. I., V. E. Smith, J. R. Sherwood, G. M. Schiff, D. S. Sander, D.DeFeudis, D. R. Spriggs, and R. L. Ward. 1998. Safety and immunogenicityof live attenuated human rotavirus vaccine 89–12. Vaccine 16:381–387.

2. Bernstein, D. I., and R. L. Ward. 2004. Rotaviruses, p. 2110–2111. In R. D.Feigin, J. D. Cherry, G. J. Demmler, and S. L. Kaplan (ed.), Textbook ofpediatric infectious diseases, 5th ed. Saunders, Philadelphia, Pa.

952 MCNEAL ET AL. J. VIROL.

on Decem

ber 10, 2012 by TU

LAN

E U

NIV

http://jvi.asm.org/

Dow

nloaded from

3. Bishop, R. F., S. R. Tzipori, B. S. Coulson, J. E. Unicomb, M. J. Albert, andG. L. Barnes. 1986. Heterologous protection against rotavirus-induced dis-ease in gnotobiotic piglets. J. Clin. Microbiol. 24:1023–1028.

4. Bridger, J. C., and G. Oldham. 1987. Avirulent rotavirus infections protectcalves from disease with and without inducing high levels of neutralizingantibody. J. Gen. Virol. 68:2311–2317.

5. Bridger, J. C., G. I. Tauscher, and U. Desselberger. 1998. Viral determinantsof rotavirus pathogenicity in pigs: evidence that the fourth gene of a porcinerotavirus confers diarrhea in the homologous host. J. Virol. 72:6929–6931.

6. Ciarlet, M., M. E. Conner, M. J. Finegold, and M. K. Estes. 2002. Group Arotavirus infection and age-dependent diarrheal disease in rats: a new animalmodel to study the pathophysiology of rotavirus infection. J. Virol. 76:41–57.

7. Ciarlet, M., S. E. Crawford, C. Barone, A. Bertolotti-Ciarlet, R. F. Ramig,M. K. Estes, and M. E. Conner. 1998. Subunit rotavirus vaccine administeredparenterally to rabbits induces active protective immunity. J. Virol. 72:9233–9246.

8. Ciarlet, M., M. E. Estes, C. Barone, R. F. Ramig, and M. E. Conner. 1998.Analysis of host range restriction determinants in the rabbit model: compar-ison of homologous and heterologous rotavirus infections. J. Virol. 72:2341–2351.

9. Conner, M. E., S. E. Crawford, C. Barone, and M. K. Estes. 1993. Rotavirusvaccine administered parenterally induces protective immunity. J. Virol.67:6633–6641.

10. Conner, M. E., M. K. Estes, and D. Y. Graham. 1988. Rabbit model forrotavirus infection. J. Virol. 62:1625–1633.

11. Estes, M. K. 2001. Rotaviruses and their replication, p. 1747–1785. In D. M.Knipe and P. M. Howley (ed.), Fields virology, 4th ed., vol. 2. LippincottWilliams and Wilkins, Philadelphia, Pa.

12. Fernandez, F. M., M. E. Conner, D. C. Hodgins, A. V. Parwani, P. R. Nielsen,S. E. Crawford, M. K. Estes, and L. J. Saif. 1998. Passive immunity to bovinerotavirus in newborn calves fed colostrum supplements from cows immu-nized with recombinant SA11 rotavirus core-like particle (CLP) or virus-likeparticle (VLP) vaccines. Vaccine 16:507–516.

13. Gorziglia, M., Y. Hoshino, K. Nishikawa, W. L. Maloy, R. W. Jones, A. Z.Kapikian, and R. M. Chanock. 1988. Comparative sequence analysis of thegenomic segment 6 of four rotaviruses each with a different subgroup spec-ificity. J. Gen. Virol. 69:1659–1669.

14. Gorziglia, M., G. Larralde, A. Z. Kapikian, and R. M. Chanock. 1990.Antigenic relationships among human rotaviruses as determined by outercapsid protein VP4. Proc. Natl. Acad. Sci. USA 87:7155–7159.

15. Greenberg, H. B., V. McAuliffe, J. Valdesuso, R. Wyatt, J. Flores, A. Kalica,Y. Hoshino, and N. Singh. 1983. Serological analysis of subgroup protein ofrotavirus, using monoclonal antibodies. Infect. Immun. 39:91–99.

16. Guerin-Danan, C., J. C. Meslin, F. Lambre, A. Charpilienne, M. Serezat, C.Bouley, J. Cohen, and C. Andrieux. 1998. Development of a heterologousmodel in germfree suckling rats for studies of rotavirus diarrhea. J. Virol.72:9298–9302.

17. Hoshino, Y., L. J. Saif, K. Shien-Young, M. M. Sereno, W. K. Chen, and A. Z.Kapikian. 1995. Identification of group A rotavirus genes associated withvirulence of a porcine rotavirus and host range restriction of a humanrotavirus in the gnotobiotic piglet model. Virology 209:274–280.

18. Hoshino, Y., L. J. Saif, M. M. Sereno, R. M. Chanock. 1988. Infectionimmunity of piglets to either VP3 or VP7 outer capsid protein confersresistance to challenge with a virulent rotavirus bearing the correspondingantigen. J. Virol. 62:744–748.

19. Iturriza-Gomara. M., G. Kang, A. Mammen, A. K. Jana, M. Abraham, U.Desselberger, D. Brown, and J. Gray. 2004. Characterization of G10P(11)rotaviruses causing acute gastroenteritis in neonates and infants in Vellore,India. J. Clin. Microbiol. 42:2541–2547.

20. Iturriza-Gomara, M., C. Wong, S. Blome, U. Desselberger, and J. Gray.2002. Molecular characterization of VP6 genes of human rotavirus isolates:correlation of genogroups with subgroups and evidence of independentsegregation. J. Virol. 76:6596–6601.

21. Kalter, S. S., R. L. Heberling, A. R. Rodriguez, and T. L. Lester. 1983.Infection of baboons (Papio cynocephalus) with rotavirus (SA11). Dev. Biol.Stand. 53:257–261.

22. Kapikian, A. Z., Y. Hoshino, and R. M. Chanock. 2001. Rotaviruses, p.1787–1833. In D. M. Knipe and P. M. Howley (ed.), Fields virology, 4th ed.,vol. 2. Lippincott Williams and Wilkins, Philadelphia, Pa.

23. Leong, Y. K., and A. Awang. 1990. Experimental group A rotaviral infectionin cynomolgus monkeys raised on formula diet. Microbiol. Immunol. 34:153–162.

24. Liprandi, F., G. Lopez, I. Rodriguez, M. Hidalgo, J. E. Ludert, and N.Mattion. 1990. Monoclonal antibodies to the VP6 of porcine subgroup Irotaviruses reactive with subgroup I and non-subgroup I non-subgroup IIstrains. J. Gen. Virol. 71:1395–1398.

24a.Liprandi, F., M. Gerder, Z. Bastidas, J. A. Lopez, F. H. Pujol, J. E. Ludert,D. B. Joelsson, and M. Ciralet. 2003. A novel type of VP4 carried by aporcine rotavirus strain. Virology 314:373–380.

25. Lopez, S., R. Espinosa, H. B. Greenberg, and C. F. Arias. 1994. Mapping thesubgroup epitopes of rotavirus protein VP6. Virology 204:153–162.

26. Majer, M. F. Behrens, E. Weinmann, R. Mauler, G. Maass, H. G. Baumeis-

ter, and T. Luthardt. 1978. Diarrhea in newborn cynomolgus monkeys in-fected with human rotavirus. Infection 6:71–72.

27. Malherbe, H., and R. Harwin. 1963. The cytopathic affects of vervet monkeyviruses. S. Afr. Med. J. 37:407–411.

28. Martella, V., M. Ciarlet, A. Camarda, A. Pratelli, M. Tempesta, G. Greco, A.Cavalli, G. Elia, N. Decaro, V. Terio, G. Bozzo, M. Camero, and C.Buonavoglia. 2003. Molecular characterization of the VP4, VP6, VP7, andNSP4 genes of lapine rotaviruses identified in Italy: emergence of a novelVP4 genotype. Virology 314:358–370.

29. McNeal, M. M., J. Belli, M. Basu, A. H.-C. Choi, and R. L. Ward. 2004.Discovery of a new strain of murine rotavirus that is consistently shed in largequantities after oral inoculation of adult mice. Virology 320:1–11.

30. McNeal, M. M., M. N. Rae, J. A. Bean, and R. L. Ward. 1999. Antibody-dependent and -independent protection following intranasal immunizationof mice with rotavirus particles. J. Virol. 73:7565–7573.

31. Mitchell, J. D., L. A. Lambeth, L. Sosula, A. Murphy, and M. Albrey. 1977.Transmission of rotavirus gastroenteritis from children to a monkey. Gut18:156–160.

32. Nakagomi, O., and T. Nakagomi. 1993. Interspecies transmission of rotavi-ruses studied from the perspective of genogroup. Microbiol. Immunol. 37:337–348.

33. Oldham, G., J. C. Bridger, C. J. Howard, and K. R. Parsons. 1993. In vivorole of lymphocyte subpopulations in the control of virus excretion andmucosal antibody responses of cattle infected with rotavirus. J. Virol. 67:5012–5019.

34. Page, R. D. M. 1996. Treeview: an application to display phylogenetic treeson personal computers. Comput. Appl. Biosci. 12:357–358.

35. Parashar, U. D., E. G. Hummelman, J. S. Bresee, M. A. Miller, and R. I.Glass. 2003. Global illness and deaths caused by rotavirus disease in chil-dren. Emerg. Infect. Dis. 9:565–571.

36. Petschow, B. W., R. E. Litov, L. J. T. Young, and T. P. McGraw. 1992.Response of colostrum-deprived cynomolgus monkeys to intragastric chal-lenge exposure with simian rotavirus strain SA11. Am. J. Vet. Res. 53:674–678.

37. Rao, C. D., K. Gowda, and B. S. Y. Reddy. 2000. Sequence analysis of VP4and VP7 genes of nontypeable strains identifies a new pair of outer capsidproteins representing novel P and G genotypes in bovine rotaviruses. Virol-ogy 276:104–113.

38. Saitou, N., and M. Nei. 1987. The neighbor-joining method: a new methodfor reconstructing phylogenetic trees. Mol. Biol. Evol. 4:406–425.

39. Sestak, K., M. M. McNeal, A. Choi, M. J. Cole, G. Ramesh, X. Alvarez, P. P.Aye, R. P. Bohm, M. Mohamadzadeh, and R. L. Ward. 2004. DefiningT-cell-mediated immune responses in rotavirus-infected juvenile rhesus ma-caques. J. Virol. 78:10258–10264.

40. Snodgrass, D. R., and P. W. Wells. 1978. Passive immunity in rotaviralinfections. J. Am. Vet. Med. Assoc. 173:565–568.

41. Soike, K. F., G. W. Gary, and S. Gibson. 1980. Susceptibility of nonhumanprimate species to infection by simian rotavirus SA-11. Am. J. Vet. Res.41:1098–1103.

42. Stuker, G., L. S. Oshiro, and N. J. Schmidt. 1980. Antigenic comparisons oftwo new rotaviruses from rhesus monkeys. J. Clin. Microbiol. 11:202–203.

43. Tang, B., J. M. Gilbert, S. M. Matsui, and H. B. Greenberg. 1997. Compar-ison of the rotavirus gene 6 from different species by sequence analysis andlocalization of subgroup-specific epitopes using site-directed mutagenesis.Virology 237:89–96.

44. Velazquez, F. R., D. O. Matson, J. J. Calva, M. L. Guerrero, A. L. Morrow,S. Carter-Campbell, R. I. Glass, M. K. Estes, L. K. Pickering, and G. M.Ruiz-Palacios. 1996. Rotavirus infection in infants as protection againstsubsequent infections. N. Engl. J. Med. 335:1022–1028.

45. Ward, R. L. 2003. Possible mechanisms of protection elicited by candidaterotavirus vaccines as determined with the adult mouse model. Virol. Immu-nol. 16:17–24.

46. Ward, R. L., D. I. Bernstein, R. Shukla, E. C. Young, J. R. Sherwood, M. M.McNeal, M. C. Walker, and G. M. Schiff. 1989. Effects of antibody torotavirus on protection of adults challenged with a human rotavirus. J. Infect.Dis. 159:79–88.

47. Ward, R. L., D. I. Bernstein, E. C. Young, J. R. Sherwood, D. R. Knowlton,and G. M. Schiff. 1986. Human rotavirus studies in volunteers: determinationof infectious dose and serological response to infection. J. Infect. Dis. 154:871–880.

48. Ward, R. L., H. F. Clark, P. A. Offit, and R. I. Glass. 2004. Live vaccinestrategies to prevent rotavirus disease, p. 607–620. In M. M. Levine, J. B.Kaper, R. Rappuoli, M. A. Liu, and M. F. Good (ed.), New generationvaccines, 3rd ed. Marcel Dekker, Inc., New York, N.Y.

49. Ward, R. L., J. D. Clemens, D. A. Sack, D. R. Knowlton, M. M. McNeal, N.Huda, F. Ahmed, M. Rao, and G. M. Schiff. 1991. Culture adaptation andcharacterization of group A rotaviruses causing diarrheal illnesses in Bang-ladesh from 1985 to 1986. J. Clin. Microbiol. 29:1915–1923.

50. Ward, R. L., D. R. Knowlton, and M. J. Pierce. 1990. Efficiency of humanrotavirus propagation in cell culture. J. Clin. Microbiol. 19:748–755.

51. Ward, R. L., M. M. McNeal, and J. F. Sheridan. 1990. Development of an

VOL. 79, 2005 A RHESUS MACAQUE MODEL OF ROTAVIRUS CHALLENGE STUDIES 953

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adult mouse model for studies on protection against rotavirus. J. Virol.64:5070–5075.

52. Ward, R. L., O. Nakagomi, D. R. Knowlton, M. M. McNeal, T. Nakagomi, N.Huda, J. D. Clemens, and D. A. Sack. 1991. Formation and selection ofintergenogroup reassortants during cell culture adaptation of rotavirusesfrom dually infected subjects. J. Virol. 65:2699–2701.

53. Woode, G. N., N. E. Kelso, T. F. Simpson, S. K. Gaul, L. E. Evans, and L.Babiuk. 1983. Antigenic relationships among some bovine rotaviruses: serumneutralization and cross-protection in gnotobiotic calves. J. Clin. Microbiol.18:358–364.

54. Woode, G. N., S. Zheng, B. I. Rosen, N. Knight, N. E. Kelso Gourley, andR. F. Ramig. 1987. Protection between different serotypes of bovine rotavirusin gnotobiotic calves: specificity of serum antibody and coproantibody re-sponses. J. Clin. Microbiol. 25:1052–1058.

55. Wyatt, R. G., D. L. Sly, W. T. London, A. E. Palmer, A. R. Kalica, D. H. VanKirk, R. M. Chanock, and A. Z. Kapikian. 1976. Induction of diarrhea incolostrum-deprived newborn rhesus monkeys with the human reovirus-likeagent of infantile gastroenteritis. Arch. Virol. 50:17–27.

56. Yuan, L., C. Iosef, M. S. P. Azevedo, Y. Kim, Y. Qian, A. Geyer, T. V. Nguyen,K. O. Chang, and L. J. Saif. 2001. Protective immunity and antibody-secret-ing cell responses elicited by combined oral attenuated Wa human rotavirusand intranasal Wa 2/6-VLPs with mutant Escherichia coli heat-labile toxin ingnotobiotic pigs. J. Virol. 75:9229–9238.

57. Yuan, L., L. A. Ward, B. I. Rosen, T. L. To, and L. J. Saif. 1996. Systemic andintestinal antibody-secreting cell responses and correlates of protective im-munity to human rotavirus in a gnotobiotic pig model of disease. J. Virol.70:3075–3083.

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