The evolution of inflammatory mediators

Invited Review

Mediators of Inflammation, 5, 3-13 (1996)

INVERTEBBATES do not display the level of sophisti- The evolution of inflammatorycation in immune reactivity characteristic ofmammals and other ’higher’ vertebrates. Their mediatorsgreat number and diversity of forms, however,reflect their evolutionary success and hence theymust have effective mechanisms of defence to Andrew F. Rowledeal with parasites and pathogens and alteredself tissues. Inflammation appears to be animportant first line defence in all invertebratesand vertebrates. This brief review deals with the School of BioloGical Sciences, University of /ales,inflammatory responses of invertebrates and fish Swansea, Singleton Park, Swansea, SA2 8PP, OK.concentrating on the cell types involved and the Fax: (+44)(1) 792 295447.mediators of inflammation, in particular, eicosa-noids, cytokines and adhesion molecules.

Key words: Cytokines, Eicosanoids, Fish, Inflammation,Integrins, Invertebrates, Phenoloxidase system

Introduction The nature of the invertebrateinflammatory response and the cell typesinvolvedIt is ironic that one of the fathers of modern

immunology, Elie Metchnikoff, carried out his Phagocytosis is a universal phenomenonmost significant experiments in a non-mamma- within the animal kingdom that first functionedlian model, the starfish larva. While working in as a feeding mechanism in unicellular organismsthe Mediterranean at the Straits of Messina he such as amoebae and was later employed as aimplanted rose thorns into transparent starfish defensive mechanism to maintain the integrity oflarvae in which he was able to observe the more complex multicellular organisms.2 Phagocy-behaviour of blood cells that surrounded the tic blood cells have been described in organisms’foreign’ implant. From this simple observation from anthrozoans through to the ceph-he progressed to demonstrate the phagocytic alochordates4 and urochordates5 that areactivity of these cells towards bacteria and subse- believed to be the closest living relatives of thequently he applied this obseeeation made in an first vertebrates.6 As shown in Fig. 1 early multi-invertebrate to explain the role of phagocytic cellular animals, whose modern day representa-leucocytes in humans during inflammation. Later tives include sponges and coelenterates, gave risein the 1920s the French scientist Metalnikov, a to more advanced forms with a body spacepupil of Metchnikoff, marvelled at the phenom- referred to as a coelom. In most invertebratesenal ability of insect larvae to deal with injection the coelom is the main body cavity that is filledof pathogenic bacteria that would overwhelm the with fluid and cells termed coelomocytes. Not allnatural defences of the mammalian immune animals have an extensive coelom and in insects,system. molluscs and urochordates for example, theFrom these early reports it can be seen that main body cavity is a haemocoel and hence the

invertebrates and other ’lower’ animals are cells are described as haemocytes rather thancapable of mounting highly effective inflamma- coelomocytes. Some invertebrates, includingtory responses that at least match the capacity annelid worms (see Fig. 1)have both haemocytesof any mammal. Indeed, invertebrates with in their blood vascular system and coelomocytestheir lack of immune system comprising lym- in the coelom.2 Because all the main organs arephocytes and immunoglobulin, may therefore bathed in either coelomic fluid or blood, cellsbe more dependent on nonspecific defences are rapidly delivered to sites of damage or micro-such as inflammation to maintain their bial invasion making the inflammatory responseintegrity. This brief review aims to introduce the highly efficient.reader to the nature of the inflammatoryresponse in invertebrates and ’lower’ vertebrates Classification and characterization of inverte-concentrating on the nature of the cells involved brate "blood’ cells involved in inflammation: Forand the chemical mediators of this cellular a detailed appraisal of the structure and classifi-response, cation of invertebrate leucocytes the reader is

(C) 1996 Rapid Science Publishers Mediators of Inflammation Vol 5 1996 3

A F. Rowley

DEUTEROSTOMESMammals

Birds PROTOSTOMESMolluscs

Arthropods

Amphibians & Annelids

reptiles

Bony andcartilaginous fish

Evolution of the first vertebrates

Urochordates

Cephalochordates

Echinoderms

Evolution of the coelorn

Sponges and corals

FIG. 1. Simplified evolutionary tree of the animal kingdomshowing the main groups of animals referred to in the text.

directed to Ratcliffe and Rowley7 or Ratcliffe etaL8 As already mentioned, the cell type of princi-pal interest in the context of inflammation is thephagocyte. This cell type has a multitude ofnames in the literature on invertebrate bloodcells including amoebocyte, immunocyte, macro-phage, hyaline cell, granulocyte, plasmatocyte andgranular cell. It is important to stress that the useof nomenclature borrowed from mammalianhaematology, such as granulocyte and macro-phage, does not imply an evolutionary inter-relationship. Indeed, it is unclear if thephagocytic blood cells of invertebrates gave riseto either the granulocytes, macrophages or both

cell types in the vertebrates but it seems likelythat the macrophage is the more ancient of thesetwo groups of cells.9 While most invertebrateshave only a single class of phagocytic leucocytes,there are examples where morphologically dis-tinct phagocytic cells exist in some animals. Forexample, in the bivalve mollusc, Mytilus edulis,both basophilic and eosinophilic granulocytesare phagocytic (Fig. 2).m Similarly, in Ciona intes-tinalis (a urochordate, see Fig. l) hyaline andgranular amoebocytes are both actively phagocy-tic towards foreign material.5 Whether in theseanimals the two classes of phagocytic Cells arepart of a single maturation series, as in the caseof mammalian monocytes and macrophages, ordistinct cell types of different lineages, as withmammalian granulocytes and macrophages, isunknown. One approach that may resolve thisquestion is to raise monoclonal antibodies topurified populations of leucocytes and use theseas probes for ontogenetic studies. Such anapproach has been made possible by the devel-opment of density gradient centrifugation techni-ques adapted for a range of invertebrateleucocytes (Fig. 2). To date monoclonalanti-

11bodies have been produced against crustacean,molluscan,2 insectan’4 and urochordate5 leu-cocytes but they have not been employed to anygreat extent to study this problem of leucocyteinterrelationships.As well as the phagocytic leucocyte, mention

should also be made of an additional cell typefound mainly in arthropods (insects and crusta-ceans) that houses a range of mediators ofinflammation in a similar way to the mast cell inmammals. Such cells are highly unstable andfollowing wounding or contact with microbialmaterial (e.g. LPS) they degranulate, releasingfactors that influence the behaviour of phago-

FIG. 2. Mytilus edulis basophilic (b) and eosinophilic (e) granulocytes before (A) and after (B and C) separation using density gradientcentrifugation. Both the basophilic and eosinophilic granulocytes have been found to be phagocytic.1 Scale bar 20 Im. Micrographcourtesy of Dr E.A. Dyrynda.

4 Mediators of Inflammation Vol 5 1996

Inflammation and evolution

M

CR0B

AL

Eicosanoids(proinflammatory?)

Lectins(may be opsonic)

Activation of prophenoloxidase(killing factors, opsonins,

chemotactic factors?)

0 0 Lyticenzymes(lysozyme etc.)

Adhesion molecules.

UNSTABLE GRANULE-CONTAININGCELLS

Migration and activation?

PHAGOCYTES

FIG. 3. Diagrammatic representation of the behaviour of unstable granule-containing cells and phagocytes during inflammatory respon-ses in arthropods. For further details see the main text.

cytes (Fig. 3). This ’mast cell analogue’ of inverte-brates is referred to as a granular cell in crusta-ceans and cystocyte, coagulocyte or granular cellin insects.8 The nature of some of these media-tors is described later in this review.

The inflammatory processes of invertebrates:There are two main processes characteristic ofthe inflammatory response of invertebrates. Thefirst is phagocytosis and essentially this defencereaction is very similar to its mammalian counter-part with the exception of the recognitionprocess.8 The mechanisms involved in the intra-cellular killing of phagocytosed material withininvertebrate phagocytes involves various oxygen

/-617radicals formed during the respiratory burst,NO generation8’9 and hydrolytic enzymesincluding lysozyme.2 The second defence reac-tion is one of encapsulation which bears somesuperficial similarity to granuloma formation inmammals. The encapsulation response is foundduring integumental wound healing, parasiteinvasion and bacterial challenge. In this lattercase it is normally referred to as nodule forma-tion or nodulation. Both nodule formation andencapsulation are biphasic processes in arthro-pods where these events have been researchedextensively.8 The first stage involves the degranu-lation of unstable cells to release various pro-inflammatory factors (Fig. 3). The final .stageinvolves the ensheathment of this mass of cellsby phagocytes, effectively walling-off invadingparasites and microbial agents (Fig. 4A). During

FIG. 4. (A) Section through a nodule formed in the haemocoel ofan insect in response to the injection of bacteria. The centralmelanized mass consists of necrotic unstable granule-containingcells and entrapped bacteria. The outermost sheath (s) of flat-tened phagocytic cells walls off the bacteria hence stoppingthem gaining access to the rest of the insect. Scale bar 50

lam. Micrograph courtesy of Professor N.A. Ratcliffe. (B). Cuti-cular wound through an insect showing the encapsulationresponse over this area. Note the sheath (s) of surrounding pha-gocytic cells that seals off the melanized "scab’ that consists ofunstable granule-containing cells and extruded fat body (f). Ulti-mately, the epithelial cells (e), that secrete the cuticle, reformusing the phagocyte sheath as a base to migrate over. Scale bar50 btm.

wound healing the first stage plugs the wound,hence limiting blood loss, and the proceedingensheathment strengthens this haemostaticresponse and provides a framework for theregeneration of integumental tissues (Fig. 4B).

Mediators of Inflammation Vol 5 1996 5

A F Rowley

Mediators of inflammation in nocyte-stimulating hormone, met-enkephalin andsubstance P antagonize the effect of TNF- ininvertebratesMytilus in which the expression of a neutral

Cytokine-like molecules: There is much evidence endopeptidase 24.11 appears to be involved.for the existence of pro-inflammatory cytokine- Furthermore, generation of biogenic amines (epi-like molecules in both protostome and deuter- nephrine, dopamine and norepinephrine) byostome invertebrates (Fig. l). Prendergast and molluscan haemocytes is significantly reducedLiu1 were the first to show that the starfish, following stimulation with corticotrophin-releas-Asterias forbesi, contains a cytokine-like factor in ing factor by preincubation of these cells with r-the ’blood’ which stimulates monocyte chemo- IL-, IL-l[3, TNF- or TNF-[3. These, and othertaxis and macrophage activation in mammals, experiments, suggest that a link exists betweenAdditionally, this 8 kDa molecule, appropriately the neuroendocrine and immune systems ofnamed sea star factor (SSF), initiates an inflam- invertebrates involving cytokines in a similarmatory-like response in A forbesi where coelo- (homologous?) way to the situation in mammals.mocytes aggregate and ensheath pellets of In summary, there is much evidence to suggestpolymer incorporating SSF implanted in the that cytokines equivalent to their mammaliancoelom. A further 29.5 kDa IL-l-like molecule counterparts exist in invertebrates. A certainhas also been isolated from starfish by Beck and degree of caution should be expressed, however,Habicht whose biological activity can be inhib- in a too liberal interpretation of these results asited by polyclonal antisera to mammalian IL-1 we do not have available any sequence data toimplying some evolutionary sequence conserva- give insight into structural relationships betweention of this molecule. IL-I and IL-lj3-1ike mole- invertebrate and mammalian cytokines. Thecules have also been found in the urochordate, finding of apparent TNF- immunoreactive mate-Syela clava.24 This group of animals is of parti- rial associated with molluscan haemocytes, usingcular interest as they are closely related to the a polyclonal antibody to human TNF-0t illustratesancestors of the first vertebrates and hence may the problems with such an alproach to identifiT-provide clues to the immunological complexity ing cytokines in invertebrates.In the study theyof pre-vertebrates. One fraction of >10 kDa found that this polyclonal antibody reactedobtained from the haemolymph of S. clava by strongly with a 53 kDa molecule and weakly withgel filtration and chromatofocusing chromato- a 120 kDa molecule associated with these cellsgraphy, stimulated the mitogenic proliferation of that is unlike the 17 kDa mammalian TNF-0t.both Syela haemocytes and murine thymocytes, Such findings serve to remind us that antibodieswhile the fraction containing IL-la-like activity raised against human cytokines may react withonly had such activity with the murine cell unrelated molecules in animals widely separatedtype.24’25 Further studies have shown that a 17.5 by many millions of years of evolution. Alter-kDa protein from Syela with IL-1 activity also natively, invertebrate cytokine-like activity mayacts as an opsonin and chemoattractant in this reside in molecules with very different structuresanimal.26’27 to those in their mammalian counterparts. OnlyMuch attention has focused on the presence when we have purified and sequenced several

and activity of cytokines in molluscs that as a invertebrate cytokine activities will answers togroup belong to the protostome lineage (see such questions become available.Fig. 1). Not only have a variety of cytokines beenlocated immunoc_ochemically in the haemocytes The prophenoloxidase-activating system: Theof some molluscs28 but lipopolysaccharide stimu- melanization response found in the haemocyticlation of the haemocytes from the bivalve capsules and nodules formed in response tomollusc, Mytilus edulis, causes the release of foreign agents is a common feature in arthro-

s5TNF and/or IL-l-like factors from these cells.29 pods (insects and crustaceans).’ Over twentyMytilus blood cells also respond to rlL-la and years ago this association between melanin andrTNF-a by changes in their adhesive behaviour inflammation was suggested to reflect a killingand IL-1 also stimulates the chemotactic activity mechanism caused by the generation of toxicof these cells.1 The specificity of the reaction of quinones intermediate in the formation ofMytilus haemocytes to mammalian cytokines is melanin.6 Since this observation, the biochem-also suggested by the inhibitory activity of poly- istry of the cascade that yields melanin has beenclonal antibodies to either rlL-10t or TNF-a. subject to detailed examination (see References

Mention should also be made of experiments 8, 35 and 37 for reviews). Central to this systemthat appear to demonstrate a link between the is the enzyme phenoloxidase (EC 1.14.18.1)invertebrate neuroendocrine and immune found inside haemocytes or in the plasma as asystems that involves cytokine-like factors. Mela- proenzyme (prophenoloxidase). This system is



initially activated by microbial products, such as chidonic or eicosapentaenoic acids (both sub-LPS or glucans, leading to cleavage of propheno- strates for eicosanoid generation). These fattyloxidase by serine protease activity. The end acid ’rescue’ experiments reversed the effect ofresult of this pathway is the generation of a dexamethasone showing the specificity of therange of opsonic and haemostatic factors that activity of this PEA2 inhibitor. Similarly, a range ofinfluence the behaviour of other blood cells lipoxygenase and cyclooxygenase inhibitors alsoduring inflammatory responses such as nodule reduced the number of nodules formed information, encapsulation and phagocytosis, response to bacterial challenge.42 Hence, there isAlthough the prophenoloxidase activating system clear evidence for a role of eicosanoids in thishas been likened to the vertebrate complement inflammatory response although it remains to besystem,v the nature of some of the biologically determined which products are involved and theactive factors generated and their mode of gen- mechanism of their action is also unknown. Thereeration is still unclear, are several stages of nodule formation during

which eicosanoids could participate. The initialEicosanoids: As eicosanoids, in particular leuko- stage involves the degranulation of unstable cellstriene (LT) B4, have been reported to play a to release pre-formed mediators (e.g. lectins)central role in inflammation in mammals it is not together with the biosynthesis of additionalsurprising that attempts have been made to assess factors (e.g. prophenoloxidase-derived productsthe potential of these compounds as mediators of and pro-inflammatory eicosanoids?) (Fig. 3). Theinflammation in invertebrates. With the exception second stage involves the ensheathment of thisof arthropod venom,8 invertebrates do not mass of degranulated cells by phagocytes to formappear to express the 5-1ipoxygenase and LTA a mature nodule. Potentially, eicosanoids couldhydrolase activities required for the generation of be involved in this second stage by modifying theLTB4.39 Cyclooxygenases are, however, found in adhesive properties of phagocytes or initiatingall invertebrates examined to date9 and hence their migrative behaviour to allow them toprostaglandins (PG) are potential candidates for become incorporated in the nodules.playing a role in mediating inflammatory respon-ses in these animals. Only a few studies have Adhesion molecules: Although some adhesionexamined the eicosanoid generating capacity of molecules have been characterized in inverte-invertebrate leucocytes. For example, crab (Carci- brates little was known until recently about theirnus maenas) blood cells can synthesize both role in inflammation. The integrin family of celllipoxygenase and cyclooxygenase derivatives surface adhesion molecules appears to have aincluding 8(R)-hydroxyeicosatetraenoic acid (8- long evolutionary history and examples of theseHETE), 8(R)-hydroxyeicosapentaenoic acid (8- molecules have been found in Drosophila4 andHEPE), PGE2, and thromboxane B2.40 Similarly, in the freshwater crayfish, Pacifastacus leniuscu-an insect, Manduca sexta, the haemocytes gen- lUS.44 In this latter example, the integrin-likeerate 15-HETE as their major product, with PGE2, molecule has been found to contain the char-PGD2, PGFiu and PGA2 as the main cycloox- acteristic RGD sequence (Arg-Gly-Asp) thatygenase-derived products.41 In both cases, inhibi- represents the functional binding site to itstion of presumptive lipoxy-genase and cyclo- ligand(s).44’45 The P. leniusculus adhesion mole-oxygenase-derived product generation can be cule is a 76 kDa protein that causes degranula-

40 41achieved with specific inhibitors. tion of crayfish granular blood cells44’46 therebyRecently reported experiments have given causing the activation of the prophenoloxidase

insight into the possible role of eicosanoids as system (see Fig.3) which in turn promotesinflammatory mediators in insects. These studies encapsulation activity.47 A similar factor has alsoused nodule formation as the assay system where been found in another crustacean, the crab, Car-insect larvae of the tobacco hornworm (M. cinus maenas.48 This 80 kDa protein found insexta) were injected with bacteria (Serratia mar- the granular haemocytes acts as an opsonincescens) and the size and number of nodules enhancing the phagocy.ic ability of hyaline bloodformed in the haemocoel in response to this cells of this animal.8 This protein, and itsparticulate insult determined.42 They found that equivalent in other species, may be the opsonicprior injection of the phospholipase A2 (PLA2) principle generated by the prophenoloxidaseinhibitor, dexamethasone, caused a dose-depen- system in insects and crustaceans during thedent inhibition of the nodule formation response degranulation response in unstable granule-con-to S. marcescens. As PEA2 is required for the taining haemocytes. Further evidence for the roleprovision of free fatty acid precursors for eic0sa- of integrins in the defence reactions of inverte-noid biosynthesis, some insects were also brates comes from recent interesting studiesinjected with dexamethasone together with ara- where Sepharose beads were conjugated to the


A E Rowley

peptide, RGDS, and then incubated with haemo-cytes from the moth, Pseudoplusia includens.49

Beads conjugated to this peptide were encapsu-lated by these blood cells while beads withoutpeptide or beads with RGES were notensheathed. Furthermore, soluble RGDS, but notRGES, inhibited this encapsulation response.These results imply that encapsulation involvesan adhesion molecule with the characteristicRGD recognition motif.

Insight into a further potential adhesion mole-cule and its function in inflammation comes fromthe use of a monoclonal antibody raised againstthe haemocytes of the wax moth, Galleria mello-nella.5 This antibody reacts with an approx. 100kDa molecule found associated with the unstablegranular haemocytes that play a role in the firststage of nodule formation.8 Blocking the actionof the protein with this monoclonal antibodycauses a reduction in the adhesion of wax mothhaemocytes to glass substrates and nodule for-mation in vivo.49 Unfortunately, the structure ofthe 100 kDa protein remains to be determinedand so no sequence comparisons with otheradhesion molecules can be made.

The nature of the inflammatory responsein "lower" vertebrates and the cell typesinvolved

The most significant stage in the evolution ofthe immune system came about with the appear-ance of the first vertebrates. These were prob-ably the first animals with ’true’ lymphocytes,with the ability to respond by clonal selectivityupon challenge. Furthermore, these animalswould have had the ability to synthesize ’true’immunoglobulins (i.e. molecules with variableregions) that specifically interact with non- oraltered-self materials. The modern day ancestorsof these first vertebrates are fish (Fig. 1). Theearliest vertebrates were jawless (agnathous) fishand the only animals to retain this feature arelampreys and hagfishes, thought to be the ances-tors of some of the early vertebrates. All otherfish are jawed and these include the two maindivisions of cartilaginous (e.g. sharks, rays) andbony forms (e.g. trout, carp etc.). Hence fish area useful group to examine in this review on thephylogeny of inflammation and the following sec-tions highlight the changes brought about in theinflammatory response with their evolution frominvertebrate ancestors.

of mammalian blood, i.e. granulocytes andmonocytes/macrophages, also evolved at thisstage. Hence all vertebrates have remarkablysimilar leucocyte types reflecting a close associa-tion and a common ancestry. The only possibleexception may be mast cells, although some fishhave cells in the stratum compactum of the ali-mentary canal (Fig. 5), the dermis, gills andswimbladder with similar structural and func-tional properties to mammalian mast cells.51’52

Mast cells have been clearly identified in all othervertebrates.An area of some controversy is that of granu-

locyte heterogeneity in fish. Some species of fishhave been reported to have neutrophilic, eosino-philic and basophilic granulocytes in peripheralblood, yet others may only have a single mor-phological type. Even more curious is the obser-vation that at different stages in the life cycle ofthe same species there may be different types ofgranulocytes present. An example of this is in thelamprey (Lampetra fluviatilis) where both neu-trophilic and eosinophilic granulocytes are foundin the larval stage yet in the adult only the formercell type is present in the blood stream (Fig. 6).5In cartilaginous fish there may also be severaldifferent morphological types of eosinophilicgranulocytes in the same species (Fig. 6), someof which appear to function in a manner equiva-lent to mammalian neutrophils.5-55 Two mainconclusions can be drawn from these findings.Firstly, the staining characteristics of fish granulo-cytes (i.e. eosinophilic, basophilic etc.) do not

Leucocyte ypes involved in inflammation: Notonly did the lymphocyte probably make its firstappearance during the evolution of the verte-brates but the other leucocyte types characteristic

FIG. 5. Histological appearance of cells (unlabelled arrows) in theintestine of the rainbow trout, Oncorhynchus mykiss, thought tobe functionally analogous to the mast cells of higher vertebrates.Scale bar 50 pm.



FIG. 6. Electron micrographs showing the structural diversity of fish granulocytes. (A, B). Eosinophilic granulocytes in the dogfish, Scy-liorhinus canicula. (C). Neutrophilic granulocyte from the adult lamprey, Lampetra fluviatilis, containing a bacterium (unlabelled arrow)at an early stage of ingestion. (D). Granule sub-structure in neutrophil of L. fluviatilis. Scale bars lm (A-C) and 0.2 lm (D).

always mirror functional diversity and secondly,that there is no common evolutionary trend ingranulocyte heterogeneity within the differenttypes of fish.

The inflammatory response in fish: This has been56 57the subject of recent excellent reviews and

hence this following section is only included topresent some more recent findings and highlighttopics of particular interest to the reader. Thereare many descriptions of inflammatory exudateformation in fish following experimental chal-lenge or in naturally infected fish. Several simila-rities exist between the mammalian and piscineacute inflammatory responses. For example, thecellular involvement in inflammation in fishappears to be biphasic with an influx of granulo-cytes followed by a later arrival of monocytes/macrophages.5 Both cell types are also actively

phagocytic.57 Some key differences do exist,however, between the response in fish andmammals, in particular the dynamics and inten-sity of this reaction. Most studies have reported aprotracted inflammatory response in fish wherepeak numbers of granulocytes and macrophagesoccur at about 1-2 days and 2-7 days respec-tively post-challenge.5< In carp, the granulo-cytes that migrate to sites of inflammationoriginate from the head-kidney,5 a haemopoietic

55tissue equivalent to mammalian bone marrow,while the macrophages in exudates appear tooriginate from blood-derived monocytes. The siteof monocytopoiesis in bony fish is usually thehead-kidney and/or spleen.55 Once at the site ofinflammation, macrophages may become stimu-lated with increased phagocytic potential andenhanced antimicrobial activity.59

As would be expected, the sequence of events


A F. Rowley

during phagocytosis (chemotaxis, attachment, include the elevation in a number of macrophageingestion and intracellular digestion) are essen- activities including phagocytosis, adherence andtially the same in fish as in mammals.5v The spreading to substrates, respiratory burst andattachment of foreign material to both piscine bacterial killing,vx Recent studies have reportedgranulocytes and mononuclear phagocytes synergism between human rTNF-z and fish-appears to be aided by immunoglobulin6-62 and derived MAF in terms of respiratory burst activitycomplement fragments6 at least in some cases, in fish macrophages,v This effect could bewhile subsequently the respiratory burst leads to inhibited by prior incubation of target macro-an increase in oxygen radical generation.5v’64 phages with monoclonal antibodies to the mam-There is also evidence for the production of NO malian receptor for’ TNF-z.in fish phagocytes that is enhanced by exposureto microbial products.65’66 Various hydrolytic Adhesion molecules: The explosion in our under-enzymes are present in lysosomes and granules standing of the nature and function of adhesionin granulocytes and mononuclear phagocytes6v molecules in the control of leucocyte migrationand these presumably play a role in killing and during inflammation in mammals does notdigestion of ingested microorganisms, appear to have stimulated the search for similar

molecules in fish and other lower vertebrates.

Inflammatory mediators in fish Indeed, the only apparent report of a potentialadhesion molecule in fish comes from a study on

Cytokines: Mthough IL-l-like cytokines have been fish brain where ’foamy’ macrophages weredemonstrated in fish nothing is known about found to react with an antiserum to the 2 chaintheir potential involvement in inflammatory of human leucocyte integrins.74

responses. IL-1 has been shown to be generatedby monocytes in the catfish, Ictalurus puncta- Complement.. Although there is some evidencetus, and by macrophages and granulocytes for the existence of complement componentsfrom the carp, Cyprinus carpio.69 In catfish, poly- and associated factors in invertebrates, the evolu-clonal antisera to human IL-lz and IL-1]3 revealed tion of the ’fully-functional’ pathways of thisimmunopositive bands in Western blots of system appears to coincide with the appearancemonocyte supernatants at 60, 43 and 30 kDa with of fishes. Hence, with the exception of possiblyIL-lz antiserum, and 70 and 21 kDa with IL-1IB agnathous and cartilaginous fish, both classicalantiserum.7 In carp, polyclonal antiserum to and alternative pathways of complement activa-human rIL-lz reacted with a 22.3 kDa protein in tion exist in lower vertebrates.75 There areWestern blots of SDS-PAGE separated macro- several reports of both chemotactic/chemoki-phage lysates while a 21.7 kDa band was revealed netic76 and opsonic77’78 activities for complementusing antiserum against IL-I.69 A further immu- factors in fish, showing that these are importantnoreactive 15 kDa band was found with both IL- pro-inflammatory molecules in such animals.lz and IL-113 antisera. Importantly, these antiserato IL-10t and IL-1]3 ablated the biological activity Eicosanoids.. The eicosanoid-generating ability ofof supernatants from stimulated carp macro- fish leucocytes has received a great deal of atten-phages in the assays employed for IL-1 activity tion in the last decade. Most studies have con-showing that at least one of the three proteins centrated on the biosynthetic capacity forthat interacted with the antibodies corresponds eicosanoid generation in macrophages. Forto the active principle in these preparations.69 example, macrophages from the head-kidney of a

Significant progress has been made in elucidat- number of species of fish have been found toing macrophage activating cytokines in fish contain 5- and 12-1ipoxygenase activities thatlargely as a result of Secombes and co-workers result in the synthesis of leukotrienes and lipox-(see Reference 71 for review). Macrophage acti- ins from endogenous or exogenous arachidonicvating factor (MAF) can be generated by incubat- (20:4,n-6) and eicosapentaenoic (20:5,n-3)ing head-kidney leucocytes with T cell mitogens acids.79-82 Challenge of macrophages from theand the cell type directly responsible in its gen- head-kidney of the rainbow trout, Oncorhynchuseration belongs to a population of surface Ig- mykiss, with microbial factors (LPS, glucans) or

cell-like). Activity resides in 19 calcium ionophore results in the rapid synthesislymphocytes (T 72

and 32 kDa fractions although the active princi- of both lipoxygenase and cyclooxygenase prod-pie(s) have not been isolated and sequenced to ucts including 12-HETE, 12-HEPE, lipoxin (LX)date.71 Several pieces of evidence suggest that A4, ERa5, LTB4, LTB5 and PGE2. Although thisMAF is a form of IFN-7 although the biological overall profile of products is similar to that foundactivity of fish MAF cannot be replaced by in mammalian macrophages it differs in the mag-human IFN-T.71 The biological properties of MAF nitude of the amounts generated. The lipoxin



generating capacity of rainbow trout macro- 4soo-

phages is about four to five times greater thanreported in mammalian macrophages under the 00-

same conditions.79 The greater amounts oflipoxin formed in some species of fish has led to 2700-the rather simplistic suggestion that these com-pounds may be more important in fish than in

" 1800mammals]9 Recently, an 18 kDa protein thatappears to be the forerunner of 5-1ipoxygenaseactivating protein (FLAP), has been found in 00-

lysates of trout macrophages.8 FLAP has beenfound to be essential for cellular leukotriene bio- 0

synthesis in a range of mammalian leucocytetypes.84

Several of the main eicosanoids generated byfish leucocytes have been found to be involvedin inflammatory responses in these animals. Evi-dence supporting this viewpoint comes fromboth in vivo and in vitro experiments. Intraper-

4-itoneal injection of microbial products, such aszymosan or adjuvant, into fish results in an influxof leucocytes into the main body cavity with thetypical protracted dynamics already described.Aspiration of the exudate formed followed by "o 2-

quantification of eicosanoid levels by enzymeimmunoassay has demonstrated significantincreases in the amounts of LXA4, LTB4 andPGE2 (Fig. 7A).85 In rainbow trout infected with

0proliferative kidney disease the causative agent,probably a myxosporean parasite, multiplies inthe kidney, leading to a strong inflammatory

"r

PGE LXA4LTB4Eicosanoid

PGE2 LTB4 LXA4Eicosanoid

FIG. 7. Eicosanoid levels in experimentally induced and naturallyresponse characterized b8Y6 an increase in the infected trout tissues. (A). Levels of PGE2, LTB4 and LXA4 innumber of macrophages. Biopsies of infected inflammatory exudates from trout injected 18h previously with

kidney show a significant increase in PGE2 activ- either zymosan I--1, or saline alone . (B). Eicosanoid levels inkidney biopsies from trout uninfected or infected with pro-

ity in comparison with that in normal, uninfected liferative kidney disease. In both cases, the eicosanoid levelskidney tissue (Fig. 7B). While the increase in the were quantified by enzyme immunoassay. Values shown are

amounts of eicosanoJds found in vivo suggests means -t- S.D., n 3, *p < 0.05. Data from Reference 85.

an involvement of these compounds in inflam- E], Uninfected; ,, infected.

mation, it could also be argued that it simplyreflects the increase in leucocyte numbers in chemokinetic in nature could not be ascertainedsuch tissues mediated by other factors such as with this method. Experiments have been cardedcomplement. However, the finding that injection out to examine the migration-inducing activitiesof nordihydroguaiaretic acid, a lipoxygenase inhi- of LTB4 and lipoxins for trout neutrophils usingbitor, significantly reduces the number of macro- a Boyden chemotaxis chamber and checker-phages and granulocytes in the peritoneal cavity board assays.89 These allow for differentiationof trout following challenge with the bacterium between chemokinesis and chemotaxis not poss-aeromonas salmonicida, implies an active role of ible in most other assays. IX& was found to besome eicosanoids in inflammation.87 one to three times more potent at inducingAs summarized in Table 1, eicosanoids modify migration of trout neutrophils than LTB4 at all

and mediate a number of inflammatory processes concentrations tested (0.03 1 x 10-5 M).of fish as assessed with in vitro assays. For However, LTB4 was found to be a chemotacticexample, LTB4 has been shown to cause the agent for trout neutrophils while LXA4 was only amigration of fish leucocytes in vitro. In the case chemokinetic factor. In mammals, LXA4 is regar-of a cartilaginous fish, the lesser spotted dogfish, ded as an inhibitor of granulocyte migration in

r n t 90 91Scyliorhinus canicula, LTB4 causes a dose- espo se o either FMLP or LTB4. Similarly,dependent increase in the migration of eosino- IX& also inhibits ’human neutrophil transmigra-

92 93philic granulocytes in a migration under agarose tion through epithelial and endothelial cells.88assay. Whether this reaction is chemotactic or These results suggest that in mammals, IX&


At F Rowley

Table 1. Role of eicosanoids in in vitro inflammatory responses in fish

Feature Fish LXA4 LTB4 12-HETE PGE2 References

Phagocytic Trout (0. rnykiss)uptake

Enzyme release Troutduring phagocytosis

Respiratory burst Troutactivity

Leucocyte Troutmigration

DogfishS. canicu/a)

Stimulation

NT NT

Stimulation(chemokinetic)NT

Stimulation Stimulation 94

Inhibition 85

NT Inhibition 95

Stimulation NT NT 89(chemotactic)Stimulation NT NT 88

Key: No effect; NT, not tested.

inhibits several key events during inflammatoryresponses, while in fish it appears to be pro-inflammatory at least in the absence of otherchemotactic agents. PGE2 is the only other eico-sanoid to be studied in detail in terms of itspotential involvement in the nonspecific cellulardefences of fish (Table 1). It is rather para-doxical that PGE2 is a potent stimulator of theuptake of yeast particles by macrophages,94 yet inthe same cell type it inhibits both respiratoryburst activity95 and degranulation5 that followthe ingestion process.

References1. Metalnikov S. PhagocTtose et r6actions des ceilules dans l’immunit6. Ann

Inst Pasteur Paris 1924; 38: 787-826.2. Dales RP. Aspects of the evolution and development of body cavities,

circulatory systems and "blood cells". In: Ratcliffe NA, Rowley AF,eds. Invertebrate Blood Cells Vol I. London: Academic Press, 1981;3-16.

3. Patterson MJ, Landor ML. Cellular reaction to injury in the anthrozoanAntbopleura elegantissima. J Invertebr Patbo11979; 33: 189-196.

4. Rhodes CP, Ratcliffe NA, Rowley AF. Presence of coelomocytes in theprimitive chordate amphioxus (Brancbiostoma lanceolatum). Science NY1982; 217: 263-265.

5. Rowley AF. The blood ceils of the sea squirt, Oona intestinally, mor-phology, differential counts and in vitro phagocytic activity. J InvertebrPatbo11981; 37: 91-100.

6. Kardong KV. Vertebrates, Comparative Anatomy, Function, Evolution.Dubuque: Wm. C. Brown Publishers. 1995; 777.

7. Ratcliffe NA, Rowley AF. Invertebrate Blood Cells Vols & 2. London:Academic Press, 1981; 641.

8. Ratcliffe NA, Rowtey AF, Fitzgerald SE, Rhodes CP. Invertebrate immunity:basic concepts and recent advances. Int Rev Cyto11985; 97: 183-329.

9. Auger MJ, Ross JA. The biology of the macrophage. In: Lewis CE, McGeeJO’D. The Natural Immune System. The Macropbage. Oxford: IRL Press,1992; 1-74.

10. Pipe R, Coles JA, Farley S. Personal communication.11. Rodriguez J, Boulo V, Mialhe E, Bachre E. Characterisation of shrimp

hemocytes and plasma components by monoclonal antibodies. J Cell Sci1995; 108: 1043-1050.

12. Noel D, Pipe R, Elston R, Bachre E, Mialhe E. Antigenic characterizationof hemocyte subpopulations in the mussel Mytilus edulis by means ofmonoclonal antibodies. Mar Bio11994; 119: 549-556.

13. Mullett H, Ratcliffe NA, Rowley AF. The generation and characterisation ofanti-insect blood ceil monoclonal antibodies. J Cell Sci 1993; 105: 93-100.

14. Willott E, Trenczek T, Thrower LW, Kanost MP. Immunochemical identi-fication of insect hemowte populations: monoclonal antibodies distin-guish four major hemowte types in Manduca sexta. EurJ Cell Bio11994;65: 417-423.

15. Uyama T, Nishikata T, Satoh N, Michibata H. Monoclonal antibodiesspecific to signet ring ceils, and the vanadocytes of the tunicate, Ascidiasydniensis samea. J Exp Zoo11991; 259: 196-201.

16. Pipe R. Generation of reactive oxygen metabolites by the haemocytes ofthe mussel, Mytilus edulis. Dev Comp Immuno11992; 16: 111-122.

17. Adema CM, Van der Knaap WPW, Sminia T. Molluscan hemocyte-mediated cytotoxicity: the role of reactive oxygen intermediates. RevAquat Sci 1991; 4: 201-223.

18. Radomski MW, Martin JF, Moncada S. Synthesis of nitric oxide by thehemocytes of the American horseshoe crab (Limulus pol3hemus). PhilTrans Roy Soc London 1991; 334: 129-133.

19. Conte A, Ottaviani E. Nitric oxide synthase activity in molluscanhemocytes. FEBS Lett 1995; 365: 120-124.

20. Cheng TC, Rodrick GE, Foley DA, Koehler SA. Release of lysozyme fromhemolyrnph ceils of Mercenaria mercenaria during phagocytosis. JInvertebr Patbo11975; 25: 261-265.

21. Prendergast RA, Liu SH. Isolation and characterization of sea star factor.ScandJ Immuno11976; 5: 873-880.

22. Prendergast RA, Lutty GA, Scott AL. Directed inflammation: the phylogenyof tymphokines. Dev Comp Immuno11983; "7, 629-632.

23. Beck G, Habicht GS. Isolation and characterization of a primitive IL-l-likeprotein from an invertebrate. Proc Natl Acad Sci USA 1986; 83: 7429-7433.

24. Raftos DA, Cooper EL, Habicht GS, Beck G. Invertebrate cytokines: tuni-cate ceil proliferation stimulated by an interleukin l-like molecule. ProcNatlAcad Sci USA 1991; 88: 9518-9522.

25. Beck G, Vasta GR, Marchalonis JJ, Habicht GS. Characterization ofinterleukin-1 activiW in tunicates. Comp Biochem Physiol 1989;-92B:93-98.

26. Kelly KL, Cooper EL, Raftos DA. Cytokine-like activities of a humoralopsonin from the solitary urochordate Styela clava. Zool Sci 1993; 10:57-64.

27. Cooper EL, Raftos DA, Zhang Z, Kelly KL. Purification and characteriza-tion of tunicate opsonins and cytokine-like proteins. In: Stolen JS,Fletcher TC, Smith SA, Zelikoff JT, Anderson RS, S6derhll K, Weeks-Perkins BA, eds. Techniques in Fish Immunology-4, 19_95. Immunologyand Pathology of Aquatic Invertebrates. Fair Haven: SOS Publications,1995; 43-48.

28. Ottaviani E, Franchini A, Franceschi C. Presence of several cytokine-likemolecules in molluscan hemocytes. Biocbem Biophys Res Comm 1993;195: 984-988.

29. Hughes TK, Smith EM, Bamett JA, Charles R, Stefano GB. LPS stimulatedinvertebrate hemocytes: a role for immunoreactive TNF and IL-1. DevComp Immuno11991; 15: 117-122.

30. Hughes TK, Smith EM, Chin R, et al. Interaction of immunoactive mono-kines (interleukin and tumor necrosis factor) in the bivalve molluscMytilus edulis. Proc NatlAcad Sci USA 1990; 8"7: 4426-4429.

31. Stefano GB, Smith EM, Cadet P, Hughes Jr TK. HIV gp120 alteration ofDAMA and IL-10t induced chemotaxic responses in human and inverte-brate immunocytes. J Neuroimmuno11993; 43: 177-184.

32. Stefano GB, Paemen LR, Hughes Jr TK. Autoimmunoregulation: differ-ential modulation of CD10/neutml endopeptidase 24.11 by tumor necro-sis factor and neuropeptides. J Neuroimmuno11992; 41: 9-14.

33. Ottaviani E, Caselgrandi E, Franceschi C. Cytokines and evolution: effectsof IL-10t, IL-I[, TNF-0t and TNF- on the ancestral type of stressresponse. Biocbem Biopbys Res Comm 1995; 20"/: 288-292.

34. Ouwe-Missi-Oukem-Boyer O, Porchet E, Capron & Dissous C. Character-ization of immunoreactive TNF0t molecules in the gastropod Biompba-laria glabrata. Dev Comp Immuno11994; 18: 211-218.

35. S6derh K, Cerenius L, Johansson MW. The prophenoloxidase activatingsystem and its role in invertebrate defense. Ann NYAcad Sci 1994; "712:155-161.

36. Taylor RL. A suggested role for the polyphenol-phenoloxidase system ininvertebrate immunity. J Invertebr Patbo11969; 14: 427-428.

37. S6derhtll K. Prophenoxidase activating system and melanization--arecognition system of arthropods? A review. Dev Comp Immunol 1982;6: 601-611.

38. Czametzki BM, Thiele T, Rosenbach T. Evidence for leukotrienes inanimal venoms. JAllergy Clin Immuno11990; 85: 505-509.

39. Rowtey AF. Eicosanoids: aspects of their structure, function and evolu-



tion. In: Warr G, Cohen N, eds Phylogenesis ofImmune functions. BocaRaton: CRC Press Inc., 1991; 269-294.

40. Hampson AJ, Rowley AF, Barrow SE, Steadman R. Biosynthesis of eicosa-noids by blood cells of the crab, Carcinus maenas. Biochim BiophysActa 1992; 1124: 143-150.

41. Gadelhak GG, Pedibhotla VK, Stanley-Samuelson DW. Eicosanoid bio-synthesis by hemocytes from the tobacco homworm, Manduca sexta.Insect Biochem Molec Bio11995; 25: 743-749.

42. Miller JS, Nguyen T, Stanley-Samuelson DW. Eicosanoids mediate insectnodulation responses to bacterial infections. Proc Natl Acad Sci USA1994; 91: 12418-12422.

43. Gotwals PJ, Painesaunders SE, Stark KA, Hynes RO. Drosophila integrinsand their ligands. Curr Opinion Cell Bio11994; 6: 734-739.

44. Johansson MW, SCderhtll K. A peptide containing the cell adhesionsequence RGD can mediate degranulation and cell adhesion of crayfishgranular haemocytes in vitro. Insect Biochem 1989; 19: 573-579.

45. Hynes RO. Integrins: versatility, modulation, and signaling in celladhesion. Cell 1992; 69: 11-25.

46. Johansson lVlW, SCderh K. A cell adhesion factor from crayfish haemo-cytes has degranulating activity towards crayfish granular cells. InsectBiocbem 1989; 19: 183-190.

47. Kobayashi M, Johansson MWo SCderhtll K. The 76kD cell-adhesion factorfrom crayfish haemocytes promotes encapsulation in vitro. Cell TissueRes 1990; 2{$0: 113-118.

48. ThCrnquist P-O, Johansson MW, SCderhtll K. Opsonic activity of celladhesion proteins and [3-1,3-glucan binding proteins from twocrustaceans. Dev Comp Immuno11994; 18: 3-12.

49. Pech LL, Strand MR. Encapsulation of foreign targets by hemocytes of themoth Pseudoplusia includens (tepidoptera: Nocmidae) involves an RGD-dependent cell adhesion mechanism. J Insect Physio11995; 41: 481-488.

50. Mullett H, Ratcliffe NA, Rowley AF. Analysis of immune defences of thewax moth, Galleria mellonella, with anti-haemocytic monoclonalantibodies. J Insect Physio11993; 39: 897-902.

51. Vallejo Jr AN, Ellis AE. Ultrastrucmral study of the response of eosinophilgranule cells to Aeromonas salmonicida extracellular products and hista-mine liberators in rainbow trout Salmo gairdneri Richardson. Dev CompImmuno11989; 13: 133-148.

52. Reite OB, Evensen O. Mast cells in the swimbladder of Atlantic salmonSalmo salar--histochemistry and responses to compound 48/80 andformalin-inactivated Aeromonas salmonicida. Dis Aquatic Organism1994; 20: 95-100.

53. Rowley AF, Page M. Ultrastrucmral, cytochemical and functional studieson the eosinophilic granulocytes of larval lampreys. Cell Tissue Res 1985:240: 705-709.

54. Mainwafing G, Rowley AF. Studies on granulocyte heterogeneity in elas-mobranchs. In: Manning MJ, Tamer MF, eds. Fish Immunology. London:Academic Press, 1985; 57-69.

55. Rowley AF, Hunt TC, Page M, Mainwafing G. Fish. In: Rowtey AF, RatcliffeNA, eds. Vertebrate Blood Cells. Cambridge: Cambridge University Press,1988; 19-127.

56. Suzuki Y, Iida T. Fish granulocytes in the process of inflammation. AnnuRev Fish Disease 1992; 2: 73-89.

57. Secombes CJ, Fletcher TC. The role of phagocytes in the protectivemechanisms of fish. Annu Rev Fish Disease 1992; 2: 53-71.

58. MacArthur JI, Fletcher TC, Pirie BJS, Davidson BJL, Thomson AW. Perito-neal inflammatory cells in plaice, Pleuronectesplatessa L.: effects of stressand endotoxin. J Fish Bio11984; 25: 69-81.

59. Secombes CJ. Enhancement of fish phagocyte activity. Fish ShellfishImmuno11994; 4: 421-436.

60. Fujii T. Antibody-enhanced phagocytosis of lamprey polymorphonuclearleucocytes against sheep erythrocytes. Cell Tissue Res 1981; 219: 41-51.

61. Griffin BR. Opsonic effect of rainbow trout (Salmo gairdneri) antibodyon phagocytosis of Yersinia ruckeri by leukocytes. Dev Comp Immunol1983; "7: 253-259.

62. Sakai DK. Opsonization of fish antibody and complement in the immunephagocytosis by peritoneal exudate cells isolated from salmonid fishes. JFish Disease 1984; 7: 29-38.

63. Michel C, Gonzales R, Avraemeas S. Opsonizing properties of naturalantibodies of rainbow trout, Oncorhynchus mykiss (Walbaum). J FishBio11990; 37: 617-622.

64. Chung S, Secombes CJ. Analysis of events occurring within teleost macro-phages during the respiratory burst. Comp Biochem Physiol 1988; 89B:539-544.

65. Schoor WP, Plumb JA. Induction of nitric oxide synthase in channelcatfish Ictalurus punctatus by Edwardsiella ictaluri. Dis Aquat Org 1994;19: 153-155.

66. Wang R, Neumann NF, Shen Q, Belosevic M. Establishment and char-acterisation of a macrophage cell-line from the goldfish. Fish Shellfishlmmuno11995; 5: 329-346.

67. Hine PJ. The granulocytes of fish. Fish Shellfish Immuno11992; 2: 79-98.68. Clem LW, Sizemore RC, Ellsaesser CF, Miller NW. Monocytes as accessory

cells in fish immune responses. Dev Comp Immuno11985; 9: 803-809.69. Verburg-van Kemenade BM, Weyto FAA, Flike G. Carp macrophages and

neutrophils granulocytes secrete an IL-l-like factor. Dev Comp Immunol1995: 19: 59-70.

70. Elsaesser CF, Clem LW. Functionally distinct high and low molecularweight species of channel catfish and mouse IL-1. Cytokine 1994; 5: 10-20.

71. Secombes CJ. The phylogeny of cytokines. In: Thomson A, ed. The Cyto-kine Handbook 2nd edn. London: Academic Press, 1994; 567-594.

72. Graham S, Secombes CJ. Cellular requirements for lymphokine secretionby rainbow trout Salmo gairdneri leucocytes. Dev Comp Immuno11990;14: 59-68.

73. Jang SI, Hardie LJ, Secombes CJ. Elevation of rainbow trout Oncor-hynchus mykiss macrophage respiratory burst activity in macrophage-derived supematants. J Leukocyte Bio11995; 57: 943-947.

74. Dowding AJ, Maggs A, Scholes J. Diversity amongst the microglia ingrowing and regenerating fish CNS--immunohistochemical characteriza-tion using FL-1, an antimacrophage monoclonal antibody. Glia 1991; 4:345-364.

75. Horton JD, Ratcliffe NA. Evolution of immunity. In: Roitt I, Brostoff J,Male D, eds. Immunology 4th edn. London: Mosby, 1995; 15.1-15.22.

76. MacArthur JI, Thomson AW, Fletcher TC. Agents of leucocyte migrationin the plaice, Pleuronectes platessa L. J Fish Bio11985; 27: 667-676.

77. Saggers BA, Gould ML. The attachment of micro-organisms to macro-phages isolated from the tilapia Oreochromis spilurus Gunther. J FishBiol 1989; 35: 287-294.

78. Matsuyama H, Yano T, Yamakawa T, Nakao M. Opsonic effect of thethird complement (C3) of carp (Cyprinus carpio) on phagocytosis byneutrophils. Fish Shellfish Immuno11992; 2: 69-78.

79. Pettitt TR, Rowley AF, Secombes CJ. Lipoxins are major lipoxygenaseproducts of rainbow trout macrophages. FEBS Lett 1989; 259: 168-170.

80. Pettitt TR, Rowley AF, Barrow SE, Mallet AI, Secombes CJ. Synthesis oflipoxins and other lipoxygenase products by macrophages from therainbow trout, Oncorhynchus mykiss. J Biol Chem 1991; 266: 8720-8726.

81. Rowley AF. Lipoxin formation in fish leucocytes. Biochim Biophys Acta1991; 1084: 303-306.

82. Rowley AF, Lloyd-Evans PL, Barrow SE, Serhan CN. Lipoxin biosynthesisby trout macrophages involves the formation of epoxide intermediates.Biochemistry 1994; 33: 856-863.

83. Rowley AF, Knight J, Lloyd-Evans PL, Holland JW, Vickers PJ Eicosanoidsand their role in immune modulation in fish--a brief overview. Fish

Shellfish Immuno11995; 5: 549-567.84. Ford-Hutchinson AW, Gresser M, Young RN. 5-Lipox’ygenase. Annu Rev

Biochem 1994; 63: 383-417.85. Knight J. Distribution and function of lipoxins and other eicosanoids in

the rainbow trout, Oncorhynchus mykiss. PhD Dissertation, University ofWales, 1994.

86. Hendrick RP, MacConnell E, De Kinkelin P. Proliferative kidney disease ofsalmonid fish. Annu Rev Fish Disease 1993; 3: 277-290.

87. Rainger GE, Rowley AF, Pettitt TR. Effect of inhibitors of eicosanoid bio-synthesis on the immune reactivity of the rainbow trout, Oncorhynchusmykiss. Fish Shellfish Immuno11992; 2: 143-154.

88. Hunt TC, Rowley AF. Leukotriene B4 induces enhanced migration of fishleucocytes in vitro. Immunology 1986; 59: 563-568.

89. Sharp GJE, Pettitt TR, Rowley AF, Secombes CJ. Lipoxin-induced migra-tion of fish leukocytes. J Leukocyte Bio11992; 51: 140-145.

90. Lee TH, Horton CE, Kyan-Aung U, Haskard D, Crea AEG, Spur BW.Lipoxin A4 and lipoxin B4 inhibit chemotactic responses of human neu-trophils stimulated by leukotriene B4 and N-formyl-t-methionyl-L-leucyl-L-phenylalanine. Clin Sci 1989; "/7: 194-203.

91. Soyombo O, Spur BW, Lee TH. Effects of lipoxin A4 on chemotaxis anddegranulation of human eosinophils stimulated by platelet-activatingfactor and N-formyl->methionyl-.-leucyl-t-phenylalanine. Allergy 1994; 49:230-234.

92. Colgan SP, Serhan CN, Parkos CA, Delp-Archer C, Madara JL. Lipoxin A4modulates transmigration of human neutrophils across intestinal epithe-lial monolayers. J Clin Invest 1993; 92: 75-82.

93. Papayianni A, Serhan CN, Phillips ML, Rennke HG, Brady HR. Transcel-lular biosynthesis of lipoxin A4 during adhesion of platelets and neu-trophils in experimental immune complex glomerulonephritis. Kidney Int1995; 4"/: 1295-1302.

94. Knight J, Lloyd-Evans PL, Rowley AF, Barrow SE. Effect of lipoxins andother eicosanoids on phagocytosis and intracellular calcium mobilisationin rainbow trout Oncorhynchus mykiss) leukocytes. J Leukocyte Biol1993; 54: 518-522.

95. Secombes CJ, Ashton I. Personal communication.

ACKNOWLEDGEMENTS. am grateful to Professor N.A. Ratcliffe and Drs C.J.Secombes, R. Pipe, M. Page, E.A. Dyrynda, J. Knight and P.J. Vickers forallowing me to refer to their unpublished work and for their advice andhelpful discussions. The results presented in this review from the author’slaboratory were sup-ported by the Science & Engineering Research Council(GR/G/05179) and the Agricultural and Food Research Council (AG58/510).

Received 1 November 1995;accepted 10 November 1995


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