http://http://dspace.unitus.it:80 The DSpace digital repository system captures, stores, indexes, preserves, and distributes digital research material. 2013-05-26T07:24:18Z http://hdl.handle.net/2067/1665 Title: A CD4 homologue in sea bass (Dicentrarchus labrax): Molecular characterization and structural analysis Authors: Buonocore, Francesco; Randelli, Elisa; Casani, Daniela; Guerra, Laura; Picchietti, Simona; Costantini, Susan; Facchiano, Angelo M.; Zou, Jun; Secombes, Chris J.; Scapigliati, Giuseppe Abstract: CD4 is a transmembrane glycoprotein fundamental for cell-mediated immunity. Its action as a T cell coreceptor increases the avidity of association between a T cell and an antigen-presenting cell by interacting with portions of the complex between MHC class II and TR molecules. In this paper we report the cDNA cloning, expression and structural analysis of a CD4 homologue from sea bass (Dicentrarchus labrax). The sea bass CD4 cDNA consists of 2071 bp that translates in one reading frame to give the entire molecule containing 480 amino acids. The analysis of the sequence shows the presence of four putative Ig-like domains and that some fundamental structural features, like a disulphide bond in domain D2 and the CXC signalling motif in the cytoplasmic tail, are conserved from sea bass to mammals. Real-time PCR analysis showed that very high levels of CD4 mRNA transcripts are present in thymus, followed by gut and gills. In vitro stimulation of head kidney leukocytes with LPS and PHA-L gave an increase of CD4 mRNA levels after 4 h and a decrease after 24 h. Homology modelling has been applied to create a 3D model of sea bass CD4 and to investigate its interaction with sea bass MHC-II. The analysis of the 3D complex between sea bass CD4 and sea bass MHC-II suggests that the absence of a disulfide bond in the CD4 D1 domain could make this molecule more flexible, inducing a different conformation and affecting the binding and the way of interaction between CD4 and MHC-II. Our results will add new insights into the sea bass T cell immune responses and will help in the identification of T cell subsets in teleost fishes to better understand the evolution of cell-mediated immunity from fish to mammals. Description: L'articolo è disponibile sul sito dell'editore http://www.sciencedirect.com/ 2010-12-31T23:00:00Z http://hdl.handle.net/2067/1554 Title: The effect of Pediococcus acidilactici on the gut microbiota and immune status of on-growing red tilapia (Oreochromis niloticus) Authors: Ferguson, R.M.W.; Merrifield, Daniel L.; Harper, Glenn M.; Rawling, Mark D.; Mustafa, Sanaa; Picchietti, Simona; Balcàzar, Josè Luis; Davies, Simon J. Abstract: Aim: To assess Pediococcus acidilactici as a dietary supplement for on-growing red tilapia (Oreochromis niloticus). Methods and Results: Tilapia were fed either a control diet or control diet supplemented with Ped. acidilactici at 107 CFU g)1 for 32 days. Ped. acidilactici colonized the intestinal tract and significantly affected the intestinal microbial communities. PCR-DGGE revealed direct antagonism of gastric Ped. acidilactici with an endogenous uncultured bacterium during a period of reverting to nonsupplemented feeding. Light microscopy revealed that gut integrity and leucocyte levels were unaffected by Ped. acidilactici; however, blood leucocyte levels and serum lysozyme activity were elevated after 14-days’ feeding. No significant improvements in growth performance were observed at the end of the trial (day 32), but survival was significantly higher in the probiotic group. Conclusions: The study demonstrates that oral supplementation of Ped. acidilactici modulates intestinal bacterial communities in on-growing red tilapia and also stimulates some aspects of the nonspecific immune response. Significance and Impact of the study: To our knowledge this is the first study assessing the effects of probiotics on the gut microbiota of tilapia using culture-independent methods. Such methods are crucial to understand the mechanisms which underpin and mediate host benefits. Description: L'articolo è disponibile sul sito dell'editore http://onlinelibrary.wiley.com/ 2009-12-31T23:00:00Z http://hdl.handle.net/2067/1561 Title: The thyroid disruptor 1,1,1-trichloro-2,2-bis (p-chlorophenyl) ethane (DDT) prevents internalization of the TSH receptor Authors: Picchietti, Simona; Belardinelli, Maria Cristina; Taddei, Anna Rita; Fausto, Anna Maria; Pellegrino, M.; Rossi, M.; Maggio, Roberto; Giorgi, Franco Abstract: The thyroid-stimulating hormone (TSH) receptor (TSHr) was made specifically fluorescent by insertion of a tetracysteine motif (TSHr-FlAsH) into the C-terminal end and transiently transfected into COS-7 and HeLa cells. The observation that TSH administration caused the intracellular level of cAMP to increase in both TSHr-FlAsH-transfected cell types indicated that the FlAsH binding motif did not alter normal TSHr functioning. When transfected into HeLa cells and stimulated with TSH, the TSHr-FlAsH receptor exhibited a pronounced perinuclear labelling pattern, whereas labelling remained on the cell surface following pre-incubation with 1,1,1-trichloro-2,2-bis(p-chlorophenyl) ethane (DDT). Chinese hamster ovary (CHO)-TSHr cells probed with anti-TSHr antibodies were fluorescent mainly in the proximity of the plasma membrane, with fluorescence being primarily restricted to a juxta-nuclear position when exposed to 10 mU/ml TSH for 1 or 5 min. However, in the presence of DDT, the anti-TSHr fluorescence maintained a peripheral location along the cell plasma membrane, even if CHO-TSHr cells were stimulated with TSH for 1 and 5 min. To verify that DDT acted specifically on the TSHr, CHO cells transfected with the A2a receptor were used as controls. Following a 1-min stimulation with 5’-(N-ethyl-carboxamido)-adenosine, A2a receptors were gradually internalized regardless of the presence of DDT in the culture medium. Finally, immunoelectron microscopy of CHO-TSHr cells showed that a 1-min exposure to TSH sufficed to displace anti-TSHr antibodies tagged with 10- nm gold particles into coated pits and vesicles but that their superficial location was retained along the plasma membrane in the presence of DDT. Description: L'articolo è disponibile sul sito dell'editore http://www.springerlink.com/ 2008-12-31T23:00:00Z http://hdl.handle.net/2067/1562 Title: Early treatment with Lactobacillus delbrueckii strain induces rise in intestinal T cells and granulocytes and modulates immune related genes of larval Dicentrarchus labrax (L.) Authors: Picchietti, Simona; Fausto, Anna Maria; Randelli, Elisa; Carnevali, Oliana; Taddei, Anna Rita; Buonocore, Francesco; Scapigliati, Giuseppe; Abelli, Luigi Abstract: Lactobacillus delbrueckii ssp. delbrueckii (AS13B), isolated from the gut of adult Dicentrarchus labrax, was administered live to developing sea bass using rotifers and Artemia as live carriers. Immune-related gene transcripts were quantified in post-larvae at day 70 post-hatch (ph) and histology, electron microscopy and immunocytochemistry of the intestinal tissue were performed at day 74 ph. Since the probiotic was orally administered the studies were focused on intestinal immunity. In treated fish gut integrity was unaffected, while the density of T-cells and acidophilic granulocytes in the intestinal mucosa was significantly higher than in controls. Probiotic-induced increases in intestinal T-cells and total body TcR-beta transcripts are first reported in fish. Significantly lower IL-1beta transcripts and a trend towards lower IL-10, Cox-2 and TGF-beta transcription were found in the treated group. Evidence is provided that early feeding with probiotic-supplemented diet stimulated the larval gut immune system and lowered transcription of key pro-inflammatory genes. Description: L'articolo è disponibile sul sito dell'editore http://www.sciencedirect.com/ 2008-12-31T23:00:00Z http://hdl.handle.net/2067/1648 Title: Compartmentalisation of T cells expressing CD8α and TCRβ in developing thymus of sea bass Dicentrarchus labrax (L.) Authors: Picchietti, Simona; Guerra, Laura; Selleri, Luigi; Buonocore, Francesco; Abelli, Luigi; Scapigliati, Giuseppe; Mazzini, Massimo; Fausto, Anna Maria Abstract: Eggs, larvae, post-larvae and sexually immature juveniles of the teleost Dicentrarchus labrax (L.) were assayed for the expression of genes encoding the T cell receptor b and CD8a. RT-PCR of RNA extracted from larvae revealed TCRb transcripts from day 25 posthatching (ph) and CD8a transcripts from 26 days later. At day 51 ph, CD8a and TCRb mRNAs were localised by in situ hybridisation in thymocytes of the outer and lateral zones of the thymic paired glands. From day 75 ph onwards the signal was mainly detected in the outer region, drawing a cortex–medulla demarcation. In 1-year-old fish, CD8a+ and TCRb+ thymocytes almost filled the cortex and extended in large cords in the medulla. A CD8a TCRb+ subcapsular lymphoid zone was evident near the septa coming from the inner connective capsule that delimited the thymus. The localisation of CD8a and TCRb transcripts demonstrated a compartmentalisation of the juvenile thymus due to distinct localisation of thymocytes at different developmental stages. Description: L'articolo è disponibile sul sito dell'editore http://www.sciencedirect.com/ 2007-12-31T23:00:00Z http://hdl.handle.net/2067/1651 Title: Effects of administration of probiotic strains on GALT of larval gilthead seabream: immunohistochemical and ultrastructural studies Authors: Picchietti, Simona; Mazzini, Massimo; Taddei, Anna Rita; Renna, Raffaella; Fausto, Anna Maria; Mulero, Victoriano; Carnevali, Oliana; Cresci, Alberto; Abelli, Luigi Abstract: Two bacterial strains Lactobacillus fructivorans (AS17B), isolated from adult seabream (Sparus aurata L.) gut, and Lactobacillus plantarum (906), isolated from human faeces, were administered contemporaneously during seabream development using Brachionus plicatilis and/or Artemia salina and dry feed as vectors. Experimental group A received the probiotic strains already via rotifers from day 5 post-hatch (ph), whereas treatment of group B began with Artemia feeding from day 27 ph. Fish were sampled at day 28 ph (group A and control) and day 99 ph (groups A, B and control) for electron microscopy, histology and immunohistochemistry with the polyclonal antiserum ORa against homologous serum Ig and the mAb G7 specific for seabream acidophilic granulocytes. In all groups, timing and pattern of differentiation of the digestive tract did not differ. Furthermore, neither tissue damage nor manifest inflammation was provoked by probiotic administration. At day 28 ph, the developing GALTalready housed mucosal leucocytes, including Igþ cells but no acidophilic granulocytes. No differences were seen between experimental groups. At day 99 ph, the density of Igþ cells (þ51%) and acidophilic granulocytes (þ284%) was significantly higher (p < 0.05) in group A than in controls. Also group B had a higher density of Igþ cells (þ17%) and acidophilic granulocytes (þ130%) compared with controls, although less pronounced. Light and electron microscopy observations detailed the occurrence of heterogeneous populations of lymphocytes and granulocytes in the developing intestinal mucosa, and highlighted the net expansion of G7þ acidophilic granulocytes (A þ536%, B þ292% vs. control) due to probiotic administration. Description: L'articolo è disponibile sul sito dell'editore http://www.sciencedirect.com/ 2006-12-31T23:00:00Z http://hdl.handle.net/2067/1563 Title: Lymphocyte differentiation in sea bass thymus: CD4 and CD8-α gene expression studies Authors: Picchietti, Simona; Guerra, Laura; Buonocore, Francesco; Randelli, Elisa; Fausto, Anna Maria; Abelli, Luigi Abstract: Different developmental stages (from eggs to 1-year-old juveniles) of the teleost fish Dicentrarchus labrax (L.) were assayed for CD4 gene expression. RT-PCR revealed the appearance of CD4 transcripts in postlarvae from 51 days post-hatching (dph). This finding overlaps the first detection of CD8-a mRNA. Real-time PCR with specific primers quantified CD4, CD8-a and TCR-b transcripts in larvae and postlarvae (25, 51, 75 and 92 dph) and 1-year-old thymus. At 92 dph, TcR-b and CD8-a transcripts were significantly higher (P < 0.001) than in previous stages, as CD4 transcripts compared with 51 dph (P < 0.01). High levels of TCR-b and CD8-a transcripts were found in the thymus, while CD4 transcripts were lower (P < 0.05 vs. TCR-b). In situ hybridization identified CD4 mRNAs at 51 dph, localized in thymocytes of the outer and lateral zones of the thymic glands. From 75 dph on the signal was mainly detected in the outer region, drawing a cortex–medulla demarcation. Developmental expression of CD4 and CD8-a almost coincided. In each adult thymic lobe CD4þ and CD8-aþ thymocytes filled the cortex. The expression patterns of CD4 and CD8-a largely overlap, except in the medulla, where CD4þ thymocytes were isolated, while CD8-aþ ones mainly arranged in cords. These results provide new information about the thymic compartmentalization and lymphocyte differentiation pathways in a teleost, almost demonstrating that double negative thymocytes fill the cortex giving rise to further selection in the medulla. Description: L'articolo è disponibile sul sito dell'editore http://www.sciencedirect.com/ 2008-12-31T23:00:00Z http://hdl.handle.net/2067/1565 Title: CD4 homologue in sea bass (Dicentrarchus labrax): molecular characterization and structural analysis Authors: Buonocore, Francesco; Randelli, Elisa; Casani, Daniela; Guerra, Laura; Picchietti, Simona; Costantini, Susan; Facchiano, Angelo M.; Zou, Jun; Secombes, Chris J.; Scapigliati, Giuseppe Abstract: CD4 is a transmembrane glycoprotein fundamental for cell-mediated immunity. Its action as a T cell coreceptor increases the avidity of association between a T cell and an antigen-presenting cell by interacting with portions of the complex between MHC class II and TR molecules. In this paper we report the cDNA cloning, expression and structural analysis of a CD4 homologue from sea bass (Dicentrarchus labrax). The sea bass CD4 cDNA consists of 2071 bp that translates in one reading frame to give the entire molecule containing 480 amino acids. The analysis of the sequence shows the presence of four putative Ig-like domains and that some fundamental structural features, like a disulphide bond in domain D2 and the CXC signalling motif in the cytoplasmic tail, are conserved from sea bass to mammals. Real-time PCR analysis showed that very high levels of CD4 mRNA transcripts are present in thymus, followed by gut and gills. In vitro stimulation of head kidney leukocytes with LPS and PHA-L gave an increase of CD4 mRNA levels after 4 h and a decrease after 24 h. Homology modelling has been applied to create a 3D model of sea bass CD4 and to investigate its interaction with sea bass MHC-II. The analysis of the 3D complex between sea bass CD4 and sea bass MHC-II suggests that the absence of a disulfide bond in the CD4 D1 domain could make this molecule more flexible, inducing a different conformation and affecting the binding and the way of interaction between CD4 and MHC-II. Our results will add new insights into the sea bass T cell immune responses and will help in the identification of T cell subsets in teleost fishes to better understand the evolution of cell-mediated immunity from fish to mammals. Description: L'articolo è disponibile sul sito dell'editore http://www.sciencedirect.com/ 2007-12-31T23:00:00Z http://hdl.handle.net/2067/1542 Title: Microbial manipulations to improve fish health and production – a Mediterranean perspective Authors: Dimitroglou, Arkadios; Merrifield, Daniel L.; Carnevali, Oliana; Picchietti, Simona; Avella, Matteo; Daniels, Carly; Güroy, Derya; Davies, Simon J. Abstract: The interactions between the endogenous gut microbiota and the fish host are integral in mediating the development, maintenance and effective functionality of the intestinal mucosa and gut associated lymphoid tissues (GALTs). These microbial populations also provide a level of protection against pathogenic visitors to the gastrointestinal (GI) tract and aid host digestive function via the production of exogenous digestive enzymes and vitamins. Manipulation of these endogenous populations may provide an alternative method to antibiotics to control disease and promote health management. Applications of probiotics for Mediterranean teleosts can stimulate immune responses, enhance growth performance, feed utilisation, digestive enzyme activities, antioxidant enzyme activities, gene expression, disease resistance, larval survival, gut morphology, modulate GI microbiota and mediate stress responses. Although considerably less information is available regarding prebiotic applications for Mediterranean teleosts, prebiotics also offer benefits with regards to improving immune status and fish production. Despite the promising potential benefits demonstrated in current literature, obtaining consistent and reliable results is often difficult due to our incomplete understanding of indigenous fish GI microbiota and their subsequent host interactions which mediate and drive both localised and systemic host immunological responses. Additionally, the probiotic and prebiotic (biotics) mechanisms which mediate host benefits at the mucosal interface are poorly understood. Future studies focused on these interactions. utilising gnotobiotic techniques should provide a better understanding of how to extract the full potential of biotic applications to promote immune function of Mediterranean teleosts. 2010 Published by Elsevier Ltd. Description: L'articolo è disponibile sul sito dell'editore http://www.sciencedirect.com/ 2010-12-31T23:00:00Z http://hdl.handle.net/2067/1560 Title: Stimulation of gut immune system by early administration of probiotic strains in dicentrarchus labrax and sparus aurata Authors: Abelli, Luigi; Randelli, Elisa; Picchietti, Simona; Carnevali, Oliana Abstract: Early feeding (started during gut metamorphosis and establishment of the hypothalamic–pituitary–interrenal axis) with probiotic-supplemented diets, besides modifying the intestinal microflora, evoked profound effects on the physiology of fish larvae. Using rotifers and Artemia as living vectors, the autochthonous bacterium Lactobacillus delbrueckii delbrueckii or a multispecies probiotic formulation (autochthonous Lactobacillus fructivorans + Lactobacillus plantarum from human feces) were orally administered to sea bass and gilthead sea bream larvae, respectively. The treatments enhanced larval rearing (significantly increased body weight, decreased cortisol levels, and improved stress response compared with controls) and the immune system. In sea bass, the probiotic raised intestinal T cells, in keeping with increased total body TcR-β transcripts, and increased acidophilic granulocytes concomitant to lower transcription of pro-inflammatory genes (IL-1-β, TGF-β, IL-10, Cox-2). In sea bream, the multispecies probiotic formulation raised intestinal immunoglobulin (Ig+) cells and acidophilic granulocytesmainly belonging to theMAbG7+ phagocytic population. These results point to stimulatory actions of probiotics on the gut immune system that are devoid of harmful effects and that correlate with improvement of fry survival. Description: L'articolo è disponibile sul sito dell'editore http://onlinelibrary.wiley.com/ 2008-12-31T23:00:00Z http://hdl.handle.net/2067/1559 Title: Teleost intestinal immunology Authors: Rombout, Jan H.W.M.; Abelli, Luigi; Picchietti, Simona; Scapigliati, Giuseppe; Kiron, Viswanath Abstract: Teleosts clearly have a more diffuse gut associated lymphoid system, which is morphological and functional clearly different from the mammalian GALT. All immune cells necessary for a local immune response are abundantly present in the gut mucosa of the species studied and local immune responses can be monitored after intestinal immunization. Fish do not produce IgA, but a special mucosal IgM isotype seems to be secreted and may (partly) be the recently described IgZ/IgT. Fish produce a pIgR in their mucosal tissues but it is smaller (2 ILD) than the 4e5 ILD pIgR of higher vertebrates. Whether teleost pIgR is transcytosed and cleaved off in the same way needs further investigation, especially because a secretory component (SC) is only reported in one species. Teleosts also have high numbers of IEL, most of them are CD3-3 þ/CD8-a þ and have cytotoxic and/or regulatory function. Possibly many of these cells are TCRgd cells and they may be involved in the oral tolerance induction observed in fish. Innate immune cells can be observed in the teleost gut from first feeding onwards, but B cells appear much later in mucosal compartments compared to systemic sites. Conspicuous is the very early presence of putative T cells or their precursors in the fish gut, which together with the rag-1 expression of intestinal lymphoid cells may be an indication for an extra-thymic development of certain T cells. Teleosts can develop enteritis in their antigen transporting second gut segment and epithelial cells, IEL and eosinophils/basophils seem to play a crucial role in this intestinal inflammation model. Teleost intestine can be exploited for oral vaccination strategies and probiotic immune stimulation. A variety of encapsulation methods, to protect vaccines against degradation in the foregut, are reported with promising results but in most cases they appear not to be cost effective yet. Microbiota in fish are clearly different from terrestrial animals. In the past decade a fast increasing number of papers is dedicated to the oral administration of a variety of probiotics that can have a strong health beneficial effect, but much more attention has to be paid to the immune mechanisms behind these effects. The recent development of gnotobiotic fish models may be very helpful to study the immune effects of microbiota and probiotics in teleosts. Description: L'articolo è disponibile sul sito dell'editore http://www.sciencedirect.com/ 2009-12-31T23:00:00Z http://hdl.handle.net/2067/1649 Title: Monospecies and multispecies probiotic formulations produce different systemic and local immunostimulatory effects in the gilthead seabream (Sparus aurata L.) Authors: Salinas, Irene; Abelli, Luigi; Bertoni, Fabrizio; Picchietti, Simona; Roque, Ana; Furones, Dolors; Cuesta, Alberto; Meseguer, José; Esteban, Maria Ángeles Abstract: The effects of the oral administration of heat-inactivated Lactobacillus delbru¨eckii ssp. lactis and Bacillus subtilis, individually or combined, on gilthead seabream immune responses were investigated both systemically and locally in the gut. In a first experiment, seabream (65 g) were fed for 3 weeks different diets supplemented with 1 107 CFU g 1 Lactobacillus, 1 107 CFU g 1 Bacillus, or 0.5 107 CFU g 1 Lactobacillus plus 0.5 107 CFU g 1 Bacillus. Controls were fed non-supplemented diet. Six fish per group were sampled at the end of the trial and some humoral and cellular systemic innate immune parameters were evaluated. Feeding the mixture of the two killed bacteria species significantly increased natural complement, serum peroxidase and phagocytic activities compared with controls. In a second experiment, juvenile seabream (13 g) were fed for 3 weeks the same experimental diets and total serum IgM and numbers of gut IgMþ cells and acidophilic granulocytes were evaluated. All these parameters were significantly higher in the multispecies probiotic group compared to monospecies and control fed groups. Description: L'articolo è disponibile sul sito dell'editore http://www.sciencedirect.com 2007-12-31T23:00:00Z http://hdl.handle.net/2067/1666 Title: Dispositivi medici di collagene utilizzati come agenti emostatici e cicatrizzanti Authors: Taddei, Anna Rita; Picchietti, Simona; Gambellini, Gabriella; Fausto, Anna Maria; Giorgi, F.; Cervadoro, E.; Ricciuti, F. Abstract: Quattro dispositivi medici di collagene sono stati esaminati al microscopio elettronico per determinare le migliori condizioni strutturali che ne giustificano il ruolo come agenti emostatici e cicatrizzanti. I parametri che sono stati considerati più efficaci per il processo di guarigione sono la struttura interstiziale e lo spessore dei fasci di collagene che la delimitano. Spazi interstiziali troppo grandi o troppo piccoli non sono in grado di sostenere la migrazione cellulare, mentre fasce di collagene troppo fini o troppo spessi possono influenzare il tempo di persistenza del dispositivo sulla ferita. Sulla base di questi criteri, è stato trovato che i campioni di Condress realizzano il miglior compromesso tra l'estensione della struttura interstiziale e lo spessore dei fasci di collagene.; Four collagen samples were examined at the electron microscope to find out the best structural conditions satisfying their haemostatic and cicatrizing roles. Parameters considered most effective during healing process are the mesh substructure and the thickness of the collagen strands. Meshes too large or too small may not be suitable for sustaining cell migration, while collagen strands too thin or too thick may affect the actual persistence of the medical device on the wounded area. Based on this criteria, Condress samples are thought to provide the best structural compromise between extension of the mesh areas and thickness of the collagen strands. Description: L'articolo è disponibile sul sito dell'editore http://www.seuroma.com/ 2008-12-31T23:00:00Z http://hdl.handle.net/2067/2183 Title: Intestinal T cells of Dicentrarchus labrax (L.): gene expression and functional studies Authors: Picchietti, Simona; Guerra, Laura; Bertoni, Fabrizio; Randelli, Elisa; Belardinelli, Maria Cristina; Buonocore, Francesco; Rombout, Jan; Scapigliati, Giuseppe; Abelli, Luigi Abstract: Cellular and molecular data have evidenced a gut-associated lymphoid tissue in a variety of teleost species, abundantly containing T cells, whose origin, selection and functions are still unclear. This study reports CD4, CD8-α, MHCI-α, MHCII-β, rag-1 and TCR-β gene transcription along the intestine (anterior, middle and posterior segments) and in the thymus of one year-old Dicentrarchus labrax (L.). Real-time PCR findings depicted a main role of the thymus in T cell development, but also rag-1 and CD8-α transcripts are detected in the intestine, having significant expression in the posterior segment. In the whole intestine TCR-β and CD8-α exceeded CD4 transcripts. RNA ISH confirmed these data and detailed that mucosal CD8-α+ cells were especially numerous in the epithelium and in aggregates in the lamina propria. Regional differences in T cell-specific gene expressions are first described in the intestine of a bony fish. High non-specific cytotoxic activity against xenogeneic and allogeneic cells was found in lymphocytes purified from the intestinal mucosa, providing further insight into their local defence roles. Description: L'articolo è disponibile sul sito dell'editore http://www.sciencedirect.com/ 2010-12-31T23:00:00Z