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Majority of TcRβ+ T-lymphocytes located in thymus and midgut of the bony fish, Dicentrarchus labrax (L.)

Sun, 31 Dec 2006 23:00:00 GMT

Title: Majority of TcRβ+ T-lymphocytes located in thymus and midgut of the bony fish, Dicentrarchus labrax (L.) Authors: Romano, Nicla; Rossi, Francesca; Abelli, Luigi; Caccia, Elisabetta; Piergentili, Rita; Mastrolia, Lucia; Randelli, Elisa; Buonocore, Francesco Abstract: Real-time polymerase chain reaction (PCR) and in situ hybridization analyses were performed to investigate the occurrence and distribution of T-lymphocytes expressing TcRβ in intestine and lymphoid tissues of the bony fish, Dicentrarchus labrax (sea bass). Immunohistochemistry with the monoclonal antibody DLT15 (pan-T-cell marker) was carried out to compare the cytology, distribution and number of T-cells and TcRβ+ cells in the various sampled lymphoid organs. The highest TcRβ expression was revealed by real-time PCR in the thymus, with high levels also being found in the gut. In the thymus, DLT15+ and TcRβ+ cell populations were concentrated in the cortex and TcRβ+ cells were notably reactive at the cortical-medullary border, suggesting a specialized role of this region in thymocyte selection. The density of DLT15+ T-cells increased from the anterior to posterior intestine, whereas TcRβ+ lymphocytes were more numerous in the middle intestine compared with other segments. The existence, in fish thymus, of a medulla and a cortex comparable with those of mammals is revealed by this study. The concentration of TcRβ+ cells in the sea bass midgut also strongly suggests a special role of this intestinal segment in antigen-specific cellular immunity. The large population of TcRβ-/DLT15+ T-cells in the posterior gut can probably be ascribed to the TcRγδ phenotype fraction. Description: L'articolo è disponibile sul sito dell'editore http://www.springerlink.com

Stimulation of gut immune system by early administration of probiotic strains in dicentrarchus labrax and sparus aurata

Wed, 31 Dec 2008 23:00:00 GMT

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/

Early treatment with Lactobacillus delbrueckii strain induces rise in intestinal T cells and granulocytes and modulates immune related genes of larval Dicentrarchus labrax (L.)

Wed, 31 Dec 2008 23:00:00 GMT

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/

Lymphocyte differentiation in sea bass thymus: CD4 and CD8-α gene expression studies

Wed, 31 Dec 2008 23:00:00 GMT

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/

Compartmentalisation of T cells expressing CD8α and TCRβ in developing thymus of sea bass Dicentrarchus labrax (L.)

Mon, 31 Dec 2007 23:00:00 GMT

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/

Effects of administration of probiotic strains on GALT of larval gilthead seabream: immunohistochemical and ultrastructural studies

Sun, 31 Dec 2006 23:00:00 GMT

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/

Teleost intestinal immunology

Thu, 31 Dec 2009 23:00:00 GMT

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/

Monospecies and multispecies probiotic formulations produce different systemic and local immunostimulatory effects in the gilthead seabream (Sparus aurata L.)

Mon, 31 Dec 2007 23:00:00 GMT

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

Intestinal T cells of Dicentrarchus labrax (L.): gene expression and functional studies

Fri, 31 Dec 2010 23:00:00 GMT

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/