Skin-associated Lymphoid Tissue Research Articles

Differentially expressed proteins and microbial communities of the skin regulate disease resistance to Chinese tongue sole (Cynoglossus semilaevis).

Vibriosis, caused by Vibrio, seriously affects the health of fish, shellfish, and shrimps, causing large economic losses. Teleosts are represent the first bony vertebrates with both innate and adaptive immune responses against pathogens. Aquatic animals encounter hydraulic pressure and more pathogens, compared to terrestrial animals. The skin is the first line of defense in fish, constituting the skin-associated lymphoid tissue (SALT), which belongs to the main mucosa-associated lymphoid tissues (MALT). However, little is known about the function of immunity related proteins in fish. Therefore, this study used iTRAQ (isobaric tags for relative and absolute quantitation) to compare the skin proteome between the resistant and susceptible families of Cynoglossus semilaevis. The protein integrin beta-2, the alpha-enolase isoform X1, subunit B of V-type proton ATPase, eukaryotic translation initiation factor 6, and ubiquitin-like protein ISG15, were highly expressed in the resistant family. The 16S sequencing of the skin tissues of the resistant and susceptible families showed significant differences in the microbial communities of the two families. The protein-microbial interaction identified ten proteins associated with skin microbes, including immunoglobulin heavy chain gene (IGH), B-cell lymphoma/leukemia 10 (BCL10) and pre-B-cell leukemia transcription factor 1 isoform X2 (PBX2). This study highlights the interaction between skin proteins and the microbial compositions of C. semilaevis and provides new insights into understanding aquaculture breeding research.

Factor IX administration in the skin primes inhibitor formation and sensitizes hemophilia B mice to systemic factor IX administration

BackgroundFactor IX inhibitor formation is the most serious complication of replacement therapy for the bleeding disorder hemophilia B, exacerbated by severe allergic reactions occurring in up to 60% of patients with inhibitors. Low success rates of immune tolerance induction therapy in hemophilia B necessitate the search for novel immune tolerance therapies. Skin-associated lymphoid tissues have been successfully targeted in allergen-specific immunotherapy. ObjectivesWe aimed to develop a prophylactic immune tolerance protocol based on intradermal administration of FIX that would prevent inhibitor formation and/or anaphylaxis in response to replacement therapy. MethodsWe measured FIX inhibitor, anti-FIX immunoglobulin G1, and immunoglobulin E titers using the Bethesda assay and enzyme-linked immunosorbent assay after 4 weeks of twice-weekly intradermal FIX or FIX-Fc administration followed by 5 to 6 weeks of weekly systemic FIX injections in C3H/HeJ hemophilia B mice. We also measured skin antigen-presenting, follicular helper T, and germinal center B cell frequencies in skin-draining lymph nodes after a single or repeat intradermal FIX administration. ResultsIntradermal administration enhanced FIX inhibitor formation in response to systemic administration. We further found that intradermal administration alone triggers inhibitor formation, even at a low dose of 0.4 IU/kg, which is 100-fold lower than the intravenous dose of 40 IU/kg typically required to induce inhibitor development in hemophilia B mice. Also, intradermal administration triggered germinal center formation in skin-draining lymph nodes and sensitized mice to systemic administration. Factor IX–Fc fusion protein did not modulate inhibitor formation. ConclusionIntradermal FIX administration is highly immunogenic, suggesting that the skin compartment is not amenable to immune tolerance induction or therapeutic delivery of clotting factors.

CLA+ memory T cells in atopic dermatitis

Circulating skin-homing cutaneous lymphocyte-associated antigen (CLA)+ T cells constitute a small subset of human memory T cells involved in several aspects of atopic dermatitis: Staphylococcus aureus related mechanisms, the abnormal Th2 immune response, biomarkers, clinical aspects of the patients, pruritus, and the mechanism of action of targeted therapies. Superantigens, IL-13, IL-31, pruritus, CCL17 and early effects on dupilumab-treated patients have in common that they are associated with the CLA+ T cell mechanisms in atopic dermatitis patients. The function of CLA+ T cells corresponds with the role of T cells belonging to the skin-associated lymphoid tissue and could be a reason why they reflect different mechanisms of atopic dermatitis and many other T cell mediated skin diseases. The goal of this review is to gather all this translational information of atopic dermatitis pathology.

Modulation of immune genes in the mucosal-associated lymphoid tissues of cobia by Sarcodia suae extract.

Rachycentron canadum (cobia) is a marine fish species of high economic value in aquaculture due to its fast growth rate and good feed conversion efficacy. Regrettably, the industry has been affected by significant setbacks from high mortality due to diseases. Consequently, an improved perception of innate immunity correlated to each mucosal-associated lymphoid tissue (MALT) in teleost fish is necessary to understand hosts' response towards infections better. The utilization of polysaccharides in seaweed to stimulate the immune system has gathered unprecedented attention. The present study examined the immunostimulatory effects of Sarcodia suae water extracts (SSWE) on in vivo gill-, gut- and skin-associated lymphoid tissues (GIALT, GALT, and SALT) via immersion and oral ingestions. The GIALT genes (TNF-α, Cox2, IL-1β, IL-6, IL-8, IL-17A/F1-3, IL-11, IL-12, IL-15, IL-18, MHCIa, IgM, and IgT) except IL-10 recorded positive upregulations in a dose-dependent manner post 24h immersion in SSWE, indicating the algae extract contained bioactive compounds that could stimulate the immune genes. The upregulation of IL-12, IL-15, and IL-18 in the gills and hindgut post-SSWE immersion indicated that the extract could promote Th1-related responses in the MALTs. The modulation of immune gene expressions in the feeding trial was less potent than in the SSWE immersion. These findings indicated that the SSWE stimulated robust immune responses in both the GIALT and GALT of cobia. This suggests that the SSWE could be further explored as an effective immersive stimulant for fish, enhancing their immune system against pathogens.

Lipid mediators in the regulation of innate and adaptive immunity.

Lipid mediators in the regulation of innate and adaptive immunity.

Research progress and prospect in mucosal B cells and immunoglobulins of teleost fish

<p indent="0mm">Fish live in a microbially rich and complex aquatic environment, which exposes their mucosal surfaces to a variety of attacks from external pathogens. Teleost fish have evolved unique mucosa-associated lymphoid tissues (MALTs) that serve as the first line of defense against pathogens. So far, seven MALTs in teleost fish have been described, including gut-associated lymphoid tissue (GALT), skin-associated lymphoid tissue (SALT), gill-associated lymphoid tissue (GIALT), nasal-associated lymphoid tissue (NALT), buccal-associated lymphoid tissues, pharyngeal-associated lymphoid tissues, and the newly discovered swim bladder-associated lymphoid tissues. Because teleost MALT lacks lymph nodes, it has only evolved as a network of diffuse leucocytes within the mucosal epithelia, which is known as diffuse MALT (D-MALT). Teleost fish, unlike invertebrates, have evolved the cardinal elements of adaptive immunity to protect themselves from pathogens in their aquatic environment. Mucosal B cells and immunoglobulins (Igs) in teleost MALTs, in particular, are important players in local mucosal adaptive immune responses. In teleost fish, the three bona fide immunoglobulin isotypes (i.e., IgM, IgD, and IgT) can be found in varying proportions in MALT secretions, and the IgT/IgM ratio in mucus is much higher than that in serum in the absence of antigenic stimulation. A couple of functional studies have recently revealed that IgM and IgT responses are specialized in systemic and mucosal compartments, respectively. The primary role of Igs in adaptive immune responses has been conserved throughout evolution, as they can neutralize pathogens or promote their elimination on mucosal surfaces, preventing further infection. Teleost fish lack organized lymphoid structures known as O-MALT (e.g., Peyer’s patches and tonsils), but B-cells could locally proliferate and generate pathogenic-specific Igs in the MALTs, indicating that MALT in teleosts may function as both an inductive and effector site. Mucosal surfaces in teleost MALT harbor an incredibly dense and diverse commensal microbiota, which is one of the conserved features. Notably, a significant portion of the commensal microbiota is coated with secreted Igs (sIgs), with IgT being the predominant isotype associated with those bacteria. Recent advances in bacterial flow cytometry combined with high-throughput sequencing have aided in the identification of IgT-coated bacteria and shed light on the biological implications of sIgs coating commensal microbiota. Teleost fish secretory IgT, like mammalian and bird IgA, may target mucosal pathogens for elimination, and coating on the surface of microbiota allows for commensal colonization and homeostasis. Therefore, studying and revealing the immunological mechanism of fish MALT in anti-infection and maintaining mucosal commensal homeostasis is extremely important in fish immunology and even vertebrate comparative immunology in general. We summarize the current research process on the composition of the fish mucosal immune system, the function of mucosal B cells and Igs against pathogen infections, and the interactions between sIgs and microbiota in this review. Finally, we outline the future prospects for fish mucosal immunity, with the goal of providing a reference from a mucosal vaccination standpoint for the prevention and control of fish diseases.

006 Conventional dendritic cell 2 as an activator for cytotoxic T lymphocytes in the elicitation phase of murine contact hypersensitivity

Cytotoxic T lymphocyte (CTL) has been found to be activated by cutaneous dendritic cell (DC) in inducible skin-associated lymphoid tissue (iSALT) in a murine contact hypersensitivity (CHS) model. Cutaneous DCs are classified into Langerhans cell (LC), conventional DC1 (cDC1), conventional DC2 (cDC2) and monocyte-derived DC (MoDC); however, which DC subsets activate CTL within iSALT during the elicitation phase of CHS has remained unclear. To clarify this, we used Langerin-diphtheria toxin receptor (DTR), XCR1-DTR and CD301b-DTR mice to deplete LC, cDC1 and cDC2, respectively.

The complexity of cancer immunotherapy illustrated through skin tumors.

Skin tumours are among the cancer types most sensitive to immunotherapy, due to their unique immunogenic features including skin-associated lymphoid tissue, high mutational load, overexpression of tumour antigens, and high frequency of viral antigens. Despite this high immunotherapy response rate, however, ultimately most skin tumours develop similar treatment resistance to most other malignant tumours, which highlights the need for in-depth study of mechanisms of response and resistance to immunotherapy. A bibliographic review of the most recent publications regarding currently in use and emerging biomarkers on skin tumors has been done. Predictive biomarkers of treatment response, biomarkers that warn of possible resistance, and emerging markers, the majority of a systemic nature, are described. Including factors affecting not only genomics, but also the immune system, nervous system, microbiota, tumour microenvironment, metabolism and stress. For accurate diagnosis of tumour type, knowledge of its functional mechanisms and selection of a comprehensive therapeutic protocol, this inclusive view of biology, health and disease is fundamental. This field of study could also become a valuable source of practical information applicable to other areas of oncology and immunotherapy.

Intestinal microbe-dependent \u03c93 lipid metabolite \u03b1KetoA prevents inflammatory diseases in mice and cynomolgus macaques

Dietary ω3 fatty acids have important health benefits and exert their potent bioactivity through conversion to lipid mediators. Here, we demonstrate that microbiota play an essential role in the body’s use of dietary lipids for the control of inflammatory diseases. We found that amounts of 10-hydroxy-cis-12-cis-15-octadecadienoic acid (αHYA) and 10-oxo-cis-12-cis-15-octadecadienoic acid (αKetoA) increased in the feces and serum of specific-pathogen-free, but not germ-free, mice when they were maintained on a linseed oil diet, which is high in α-linolenic acid. Intake of αKetoA, but not αHYA, exerted anti-inflammatory properties through a peroxisome proliferator-activated receptor (PPAR)γ-dependent pathway and ameliorated hapten-induced contact hypersensitivity by inhibiting the development of inducible skin-associated lymphoid tissue through suppression of chemokine secretion from macrophages and inhibition of NF-κB activation in mice and cynomolgus macaques. Administering αKetoA also improved diabetic glucose intolerance by inhibiting adipose tissue inflammation and fibrosis through decreased macrophage infiltration in adipose tissues and altering macrophage M1/M2 polarization in mice fed a high-fat diet. These results collectively indicate that αKetoA is a novel postbiotic derived from α-linolenic acid, which controls macrophage-associated inflammatory diseases and may have potential for developing therapeutic drugs as well as probiotic food products.

Factor IX Delivery to the Skin Primes Inhibitor Formation and Sensitizes Hemophilia B Mice to Systemic Factor IX Administration

Inhibitor formation is the most serious complication of factor (F)IX replacement therapy for hemophilia B, exacerbated by anaphylactoid reactions occurring in up to 50% of inhibitor patients. Low success rates and a high burden of immune tolerance induction (ITI) therapy necessitate the search for novel immune tolerance therapies. Skin-associated lymphoid tissues (SALT) have been successfully targeted in allergen-specific immunotherapies. In this study, we aimed to develop a prophylactic immune tolerance protocol based on intradermal (ID) administration of rFIX.In a dose-finding experiment, hemophilia B mice on C3H/HeJ genetic background (C3H/HeJ-F9tm1Dws) received twice weekly ID injections of 0.01, 0.1 or 1 IU rFIX only for four weeks, followed by one intraperitoneal (IP) and four weekly intravenous (IV) injections of 1 IU FIX co-injected with anti-allergic agents (triprolidine and ABT-491). Control animals received the IP/IV doses only. One week after the last injection, plasma and/or lymph nodes (LNs) were collected for Bethesda assay, ELISA and flow cytometry analyses.Unexpectedly, all animals developed significantly (8.9-17.6-fold, p<0.05) higher FIX inhibitor titers than the control group (mean 4.4, 3.9, 8.5 and 0.6 BU/ml in the 0.01, 0.1, 1 IU and control group, respectively). Anti-FIX IgG1 antibody levels were also significantly higher (2.7-3.4-fold, p<0.001) in all ID treated groups (mean 54.8, 68.8, 69.3 and 20.1 µg/ml in the 0.01, 0.1, 1 IU and control group, respectively). This apparent enhancement of inhibitor formation prompted analyses of plasma samples collected after four weeks of ID FIX injections only to find out whether ID treatment alone could elicit FIX inhibitor formation. Two (0.1 and 1 IU) of the three evaluated ID FIX doses led to inhibitor formation of a similar magnitude to the full-length ID/IP/IV regimen. Although most (seven out of nine) mice treated with the lowest ID dose of FIX (0.01 IU) had no detectable inhibitors, the same dose, when followed by the IP/IV treatment, resulted in a similar inhibitor response to the two higher doses (0.1 and 1 IU), suggesting that the lowest dose primed the immune responses, which were further amplified by the IP/IV regimen. Also, all ID treated animals had readily detectable anti-FIX IgG1, but the levels were smaller than after the full-length treatment (mean 17.8, 35.6 and 33 µg/ml in the 0.01, 0.1 and 1 IU groups, respectively). This suggests that the IP/IV regimen following the ID treatment enhanced mainly the total anti-FIX IgG1 response, with a lesser impact on the neutralizing antibody development.Inhibitor formation following ID treatment seemed to be driven by T follicular helper (PD1 +CXCR5 +CD4 +) and Germinal Center B cell (GL7 +CD95 +CD19 +) responses in inguinal LNs, the frequencies of which were 1.75-fold and 4-fold (p<0.05) elevated in animals treated with 1 IU FIX ID compared to control mice that received PBS only.Notably, none of the ID treated mice died of anaphylaxis despite receiving eight ID injections of FIX without anti-allergic agents. IV administration of FIX alone in C3H/HeJ-F9tm1Dws hemophilia B mice results in fatal IgE-dependent anaphylaxis beginning after fourth injection with ~20% mortality and rising with subsequent injections in the surviving mice, which necessitates the use of anti-allergic agents. Interestingly, the ID treated mice had elevated levels of anti-FIX IgE antibodies. Animals that received ID injections only or followed by IP/IV treatment had 1.5- and 3.3-fold higher (p<0.01) anti-FIX IgE levels than mice that received the IP/IV treatment only. The absence of mortality in the ID treated animals suggested that ID FIX delivery might have a neutral or protective effect against anaphylaxis despite anti-FIX IgE development. To test this hypothesis, hemophilia B mice received eight twice weekly ID doses of 1 IU FIX followed by IV or IV only, with neither group receiving anti-allergic agents at any time (n=15/group). After the first IV injection, 33.3% and 0% animals died in the ID treated and the IV only group, respectively, prompting early termination of the experiment for humane reasons.In conclusion, ID administration of FIX primes or produces strong inhibitor responses in a wide range of doses and sensitizes hemophilia B mice to systemic delivery of FIX, suggesting that the skin-associated lymphoid tissue may not be amenable to FIX tolerance induction. DisclosuresNo relevant conflicts of interest to declare.

Putative Immunological Functions of Inducible Skin-Associated Lymphoid Tissue in the Context of Mucosa-Associated Lymphoid Tissue.

Acquired immunity is orchestrated in various lymphoid organs, including bone marrow, thymus, spleen, and lymph nodes in humans. However, mucosa-associated lymphoid tissue (MALT) is evolutionally known to be emerged in the oldest vertebrates as an immunological tissue for acquired immunity, much earlier than the advent of lymph nodes which appeared in endotherms. Furthermore, the lymphocytes which developed in MALT are known to circulate within the limited anatomical areas. Thus, MALT is comprehended as not the structure but the immune network dedicated to local immunity. As for the skin, skin-associated lymphoid tissue (SALT) was previously postulated; however, its existence has not been proven. Our group recently showed that aggregations of dendritic cells, M2 macrophages, and high endothelial venules (HEVs) are essential components to activate effector T cells in the murine contact hypersensitivity model and termed it as inducible SALT (iSALT) since it was a transient entity that serves for acquired immunity of the skin. Furthermore, in various human skin diseases, we reported that the ectopic formation of lymphoid follicles that immunohistochemically analogous to MALT and regarded them as human counterparts of iSALT. These data raised the possibility that SALT can exist as an inducible form, namely iSALT, which shares the biological significance of MALT. In this article, we revisit the evolution of immunological organs and the related components among vertebrates to discuss the conserved functions of MALT. Furthermore, we also discuss the putative characteristics and functions of iSALT in the context of the MALT concept.

Local immune microenvironment of skin may play an important role in the development of pretibial myxedema.

Pretibial myxedema (PTM), characterized by the accumulation of glycosaminoglycans in dermis is an autoimmune skin disorder, which is almost always associated with Graves’ disease (GD). Although fibroblast stimulated by thyroid‐stimulating hormone receptor (TSHR) antibody, cytokines and growth factors have been postulated as target of the autoimmune process in the dermopathy, the pathogenesis of PTM remains unclear. We hypothesize that the local immune microenvironment of the skin including the antigens and antibodies, T cells, B cells, plasma cells and fibroblasts may play an important role in the development of PTM.Results obtained on PTM patients indicate increased thyroid‐stimulating hormone receptor antibodies (TRAb) in the blood positively correlate with the dermal thickness of the lesions. Further analysis shows that there were more CD3+ T cells and CD20+ B cells in the skin lesions. These T and B cells are in close contact, indicating that inducible skin‐associated lymphoid tissue (iSALT) may be formed in the area. In addition, we found that the infiltrating plasma cells can secrete TRAb, proving that B cells in the skin other than the thyroid are an additional source of TSHR antibodies. Meanwhile, the T and B cells in the skin or skin homogenate of patients can promote the proliferation of pretibial fibroblasts. In conclusion, our results provide evidence that the local immune microenvironment of the skin may play an important role in the development of PTM.

Prevailing Role of Mucosal Igs and B Cells in Teleost Skin Immune Responses to Bacterial Infection.

The skin of vertebrates is the outermost organ of the body and serves as the first line of defense against external aggressions. In contrast to mammalian skin, that of teleost fish lacks keratinization and has evolved to operate as a mucosal surface containing a skin-associated lymphoid tissue (SALT). Thus far, IgT representing the prevalent Ig in SALT have only been reported upon infection with a parasite. However, very little is known about the types of B cells and Igs responding to bacterial infection in the teleost skin mucosa, as well as the inductive or effector role of the SALT in such responses. To address these questions, in this study, we analyzed the immune response of trout skin upon infection with one of the most widespread fish skin bacterial pathogens, Flavobacterium columnare This pathogen induced strong skin innate immune and inflammatory responses at the initial phases of infection. More critically, we found that the skin mucus of fish having survived the infection contained significant IgT- but not IgM- or IgD-specific titers against the bacteria. Moreover, we demonstrate the local proliferation and production of IgT+ B cells and specific IgT titers, respectively, within the SALT upon bacterial infection. Thus, our findings represent the first demonstration that IgT is the main Ig isotype induced by the skin mucosa upon bacterial infection and that, because of the large surface of the skin, its SALT probably represents a prominent IgT-inductive site in fish.

An overview of the structural and functional aspects of immune cells in teleosts.

The immune system of fish consists of two main components, innate and adaptive immunities. Innate immunity is non-specific and acts as the primary line of protection against pathogen invasion, while adaptive immunity is more specific to a certain pathogen/following adaptation. The adaptive immune system consists of the humoral and cellular components. Cytotoxic T-lymphocyte cells are the major component of the cellular immunity that frequently kills viral-, bacterial- or parasitic-infected cells. According to the anatomical location, the mucosal-associated lymphoid tissue (MALT) in teleost fish subdivides into gut-associated lymphoid tissue (GALT), gill-associated lymphoid tissue (GIALT), and skin-associated lymphoid tissue (SALT). The MALTs contain various leukocytes; including, but not limited to, lymphocytes (T and B cells), plasma cells, macrophages, and granulocytes. Macrophages are multifunctional cells that are mainly involved in the immune response, including; phagocytosis and degradation of foreign antigens, tissue remodeling, and production of cytokines, chemokines and growth factors. An interesting feature of teleost macrophages is their ability to form melanomacrophage centers (MMC) in the hemopoietic tissues. Dendritic cells, rodlet cells, mast cells, eosinophilic granular cells (ECGs), telocytes, osteoclasts, club cells, as well as, barrier cells have been recorded in many fish species and have many immunological roles. This paper aims to summarize the current knowledge of the immune cells present in fish tissues serving as anatomical and physiological barriers against external hazards. Increased knowledge of fish immune systems will facilitate the development of novel vaccination strategies in fish.

Improving greater amberjack (Seriola dumerili) defenses against monogenean parasite Neobenedenia girellae infection through functional dietary additives

The main objective of this study was to determine the effect of two feeding additives (cMOS: Actigen®, Alltech Inc., USA) and a phytogenic specifically designed for reducing ectoparasite incidence, combining garlic and labiatae herbal extracts (HERB; Delacon, Austria) on growth performance, stress and immune response of greater amberjack (Seriola dumerili) before and after an experimental parasitization with the skin ectoparasite Neobenedenia girellae, a monogenean with high incidence on Seriola cultured in sea cages. Two parallel trials were conducted in order to determine the effect of 70 days of functional diets supplementation (0.2% cMOS and 200 ppm HERB) on greater amberjack: a) Growth performance and stress resistance and b) disease resistance against N. girellae. Additionally, in order to evaluate the effects of the dietary supplements pre- and post- parasitization challenge against N. girellae, the expression of some immune-related genes was evaluated. The relative expression of Il-1β, piscidin, hepcidin, IgT, tnf-α, muc-2, cathelicidin, complement c3, cd8, and caspase-3 was determined in skin. The activity of protease and lysozyme in serum and skin mucus were also evaluated, as well as parasite load and parasite total size.The use of both functional additives did not affect fish growth performance. However, the dietary supplementation of HERB significantly (p<0.05) reduced circulating cortisol levels after the stress challenge, whereas dietary cMOS significantly (p<0.05) reduced the parasite load and total parasite size. When comparing pre and post parasitization challenge, skin mucus protease activity was significantly (p<0.05) higher in all the treatments before parasitization, while the use of both functional additives increased skin mucus lysozyme activity after challenge. From the eleven immune genes studied, only piscidin was significantly (p<0.05) up-regulated by HERB supplementation before challenge, whereas after parasitization, muc-2 and piscidin were significantly (p<0.05) up-regulated by HERB and tnf-α, il1-β, hep, c3, cd8 and casp3 were up-regulated by both functional additives. Moreover, hep, IgT, cath, c3 and cd8 expressions were negatively correlated with the parasite load.In general, greater amberjack supplementation with cMOS and HERB at the dose used in the present study was effective for reducing stress and for increasing the skin associated lymphoid tissue (SALT) immune response against N. girellae during the infection process.

Assessment of CLA+T-cell subpopulations in the blood of patients with chronic dermatoses

Background. CLA+T-cell are an important component of skin-associated lymphoid tissue, and thus determine the pathogenesis of many immuno-mediated dermatoses.&#x0D; Aims. Determine the relative number of CLA+T-cell subpopulations in the peripheral blood of patients with psoriasis, lichen planus and atopic dermatitis, as well as assess their impact on the severity of dermatoses.&#x0D; Materials and methods. We examined 82 patients with psoriasis aged 19 to 62 years, 54 patients with lichen planus (LP) aged 18 to 54 years, 44 patients with atopic dermatitis (AD) aged 18 to 44 years, as well as 20 practically healthy individuals aged 18 to 52 years who were admitted to the clinic for the removal of benign skin neoplasms.&#x0D; All patients underwent a standard clinical examination with the determination of indicators that characterize the severity of dermatosis: PASI (Psoriasis Area and Severity Index) for patients with psoriasis, IPSLP (index of prevalence and severity of lichen planus) for patients with lichen planus and SCORAD (Scoring of Atopic Dermatitis) for patients with atopic dermatitis. Defining subpopulations CLA+T-lymphocytes were carried out on a flow cytometer Cytomics FC500 by Beckman Coulter using appropriate combinations of direct monoclonal antibodies and isotopic controls. The groups were compared using the nonparametric Mann Whitney test, and the differences were considered significant at p0,05. To analyze the relationship between the severity of dermatosis and the relative content of subpopulations CLA+T-cells used Spearman's rank correlation coefficient.&#x0D; Results. In patients with psoriasis, a significant increase in the percentage of the total number of T-lymphocytes positive for CLA (CLA+CD3+) and T-helpers positive for CLA (CLA+CD4+) (p=0,002 and 8,5104, respectively), in patients with PL and AD only CLA+CD4+ lymphocytes (p=0,028 and 0,003, respectively). In the progressive period of psoriasis, a direct moderate correlation was found between the circulating subpopulation of cytotoxic T lymphocytes positive for CLA (CLA+CD8+) and the PASI index (rs=0,47; p0,001), in the acute period of AD between the CLA+CD3+ subpopulations and CLA+CD4+ cells and the SCORAD index (rs=0,53; p 0,001 and rs=0,57; p0,001, respectively). In PL, the severity of the course of dermatosis was not accompanied by any significant changes in the CLA-positive T-cell subpopulations.&#x0D; Conclusion. The results of the study confirmed the important role of CLA+T cell subpopulations in the development of chronic dermatoses. In all groups (psoriasis, LP and AD), an increase in the relative number of CLA+CD4+ T-helpers was noted compared with the control group. The relationship between the severity of psoriasis and the relative number of CLA+CD8+ cytotoxic T-lymphocytes, and the severity of AD with CLA+CD3+ and CLA+CD4+ T-helpers is also shown.

Immunoglobulins, Mucosal Immunity and Vaccination in Teleost Fish

Due to direct contact with aquatic environment, mucosal surfaces of teleost fish are continuously exposed to a vast number of pathogens and also inhabited by high densities of commensal microbiota. The B cells and immunoglobulins within the teleost mucosa-associated lymphoid tissues (MALTs) play key roles in local mucosal adaptive immune responses. So far, three Ig isotypes (i.e., IgM, IgD, and IgT/Z) have been identified from the genomic sequences of different teleost fish species. Moreover, teleost Igs have been reported to elicit mammalian-like mucosal immune response in six MALTs: gut-associated lymphoid tissue (GALT), skin-associated lymphoid tissue (SALT), gill-associated lymphoid tissue (GIALT), nasal-associated lymphoid tissue (NALT), and the recently discovered buccal and pharyngeal MALTs. Critically, analogous to mammalian IgA, teleost IgT represents the most ancient Ab class specialized in mucosal immunity and plays indispensable roles in the clearance of mucosal pathogens and the maintenance of microbiota homeostasis. Given these, this review summarizes the current findings on teleost Igs, MALTs, and their immune responses to pathogenic infection, vaccination and commensal microbiota, with the purpose of facilitating future evaluation and rational design of fish vaccines.

Mucosal immune response of Nile tilapia Oreochromis niloticus during Gyrodactylus cichlidarum infection

Monogenean Gyrodactylus cichlidarum can cause severe mortality of Nile tilapia (Oreochromis niloticus) fry. To date, reports about mucosal immunity of O. niloticus against this parasite have been rare. In order to explore the mucosal immunity of Nile tilapia against G. cichlidarum infection, the expressions of six adaptive immune-related genes and the contents of specific immunoglobulin IgM and IgT in the skin-associated lymphoid tissues (SALT) were dynamically analyzed after primary and secondary infections. The abundances of G. cichlidarum on the hosts after secondary infection were lower than those after primary parasite infection, which implied that hosts could initiate immune protection against G. cichlidarum reinfection to some degree. The transcription levels of TCR-β and CD4 genes in the skin tissue were significantly up-regulated after primary G. cichlidarum infection, while genes pIgR and IgT were only detected with significant up-regulations during secondary infection. With the exception of pIgR, which had remarkably higher expression in the fish with low parasite loads, all other genes studied tended to have higher mRNA level in the fish with higher parasite loads. The specific IgM content in the skin mucus increased significantly on the 2nd day after the primary exposure, higher than the corresponding value during the secondary exposure, and had significantly positive correlation with the parasite loads during the first parasite infection. These results manifested that acquired immune responses in the SALT of Nile tilapia participated in the resistance against G. cichlidarum infection, underscoring the involvement of mucosal immunity in fish against monogenean infection, and suggesting potential prophylactic treatment of gyrodactylid disease of tilapia.

Innate Immune Responses of Skin Mucosa in Common Carp (Cyprinus Carpio) Fed a Diet Supplemented with Galactooligosaccharides.

Simple SummaryThe skin mucosa in fish is equipped with innate immune mechanisms, which constitute the first line of defense against potentially harmful factors in the aquatic environment. Prebiotics, such as galactooligosaccharides (GOS), mediate modulation of the immune responses. Dietary prebiotics promote the development of intestinal microbiota, which interacts with the immune system. In this study, we analyzed the effects of the GOS prebiotic applied as a feed additive on molecular responses in the skin mucosa of the common carp. The genes analyzed encode various proteins associated with the innate immune response in skin mucosa in fish, such as mucin secretion, antimicrobial peptides, and enzymes. Modulated expression of those genes at the mRNA level regulates the defense mechanisms in the skin mucosa. In this study, supplementation with GOS increased the mRNA level of interferon and lysozyme, which are involved in fighting infection. At the same time, GOS decreased the mRNA level of CRP, which is a marker of inflammation. We conclude that supplementation with GOS modulates innate immune processes in the skin mucosa of common carp. Further studies could be focused on analyzing the effects of GOS on the microbiota composition of the skin mucosa and the mitigating effects against environmental stress.Galactooligosaccharides (GOS) are well-known immunomodulatory prebiotics. We hypothesize that GOS supplemented in feed modulates innate immune responses in the skin-associated lymphoid tissue (SALT) of common carp. The aim of this study was to determine the impact of GOS on mRNA expression of the immune-related genes in skin mucosa. During the feeding trial, the juvenile fish (bodyweight 180 ± 5 g) were fed two types of diet for 50 days: control and supplemented with 2% GOS. At the end of the trial, a subset of fish was euthanized (n = 8). Skin mucosa was collected, and RNA was extracted. Gene expression analysis was performed with RT-qPCR to determine the mRNA abundance of the genes associated with innate immune responses in SALT, i.e., acute-phase protein (CRP), antimicrobial proteins (His2Av and GGGT5L), cytokines (IL1β, IL4, IL8, IL10, and IFNγ), lectin (CLEC4M), lyzosymes (LyzC and LyzG), mucin (M5ACL), peroxidase (MPO), proteases (CTSB and CTSD), and oxidoreductase (TXNL). The geometric mean of 40s s11 and ACTB was used to normalize the data. Relative quantification of the gene expression was calculated with ∆∆Ct. GOS upregulated INFγ (p ≤ 0.05) and LyzG (p ≤ 0.05), and downregulated CRP (p ≤ 0.01). We conclude that GOS modulates innate immune responses in the skin mucosa of common carp.

Role of Lymphoid Structure in Skin Immunity.

The skin is the outermost organ of the body and is exposed to many kinds of external pathogens. To manage this, the skin contains multiple types of immune cells. To achieve sufficient induction of cutaneous adaptive immune responses, the antigen presentation/recognition in the skin is an essential process. Recent studies have expanded our knowledge of how T cells survey their cognate antigens in the skin. In addition, the formation of a lymphoid cluster, named inducible skin-associated lymphoid tissue (iSALT), has been reported during skin inflammation. Although iSALT may not be classified as a typical tertiary lymphoid organ, it provides specific antigen presentation sites in the skin. In this article, we provide an overview of the antigen presentation mechanism in the skin, with a focus on the development of iSALT and its function.