Detection of CD4+ and CD8+ lymphocytes in the intestine of broiler chicks treated with lactobacillus spp. and challenged with Salmonella enterica serovar enteritidis

The expression of immune response as a leukocytic infiltrate by CD4+ and CD8+ cells in the epithelium and in the intestinal lamina propria of chicks fed Lactobacillus spp or cecal microflora (CM) and experimentally challenged or not with Salmonella enterica serovar Enteritidis (SE) was studied using immunohistochemistry. Three hundred and twenty day-of-hatch broiler chicks were divided into four groups of 80 birds each and orally received L. reuteri, L. salivarius, L. acidophilus, or CM. Each group was subdivided into four subgroups of 20 birds each, classified as follows: a subgroup did not receive any oral treatment (negative control), subgroup treated with L. spp or CM, subgroup treated with L. spp or CM and challenged with SE, and subgroup only challenged with SE (positive control). The results show that the oral treatment with L. reuteri, L. salivarius, L. acidophilus, or CM and challenge or not with SE stimulated bird immune response as determined by the leukocytic infiltrate by CD8+ lymphocytes followed by CD4+ in the epithelium and in the lamina propria of the duodenum, jejunum, and cecum of chicks up to 12 days of age. CD8+ lymphocyte number was significantly higher in the intestine of chicks receiving CM and challenged with SE. The duodenum, followed by the jejunum, were the segments in which the immune response, as shown by T, CD4+ and CD8+ cells, was stimulated with the greatest intensity.

Both CD4+ and CD8+ lymphocytes participate in the IFN-y response to filamentous hemagglutinin from Bordetella pertussis in infants, children and adults

Infant CD4+ T-cell responses to bacterial infections or vaccines have been extensively studied, whereas studies on CD8 + T-cell responses focused mainly on viral and intracellular parasite infections. Here we investigated CD8 + T-cell responses upon Bordetella pertussis infection in infants, children, and adults and pertussis vaccination in infants. Filamentous hemagglutinin-specific IFN-γ secretion by circulating lymphocytes was blocked by anti-MHC-I or -MHC-II antibodies, suggesting that CD4 + and CD8 + T lymphocytes are involved in IFN-γ production. Flow cytometry analyses confirmed that both cell types synthesized antigen-specific IFN-γ, although CD4 + lymphocytes were the major source of this cytokine. IFN-γ synthesis by CD8 + cells was CD4 + T cell dependent, as evidenced by selective depletion experiments. Furthermore, IFN-γ synthesis by CD4 + cells was sometimes inhibited by CD8 + lymphocytes, suggesting the presence of CD8 + regulatory T cells. The role of this dual IFN-γ secretion by CD4 + and CD8 + T lymphocytes in pertussis remains to be investigated. © 2012 Violette Dirix et al.

Human alveolar T lymphocyte responses to Mycobacterium tuberculosis antigens: role for CD4+ and CD8+ cytotoxic T cells and relative resistance of alveolar macrophages to lysis.

T cell-mediated cytotoxicity against Mycobacterium tuberculosis (MTB)-infected macrophages may be a major mechanism of specific host defense, but little is known about such activities in the lung. Thus, the capacity of alveolar lymphocyte MTB-specific cell lines (AL) and alveolar macrophages (AM) from tuberculin skin test-positive healthy subjects to serve as CTL and target cells, respectively, in response to MTB (H37Ra) or purified protein derivative (PPD) was investigated. Mycobacterial Ag-pulsed AM were targets of blood CTL activity at E:T ratios of > or = 30:1 (51Cr release assay), but were significantly more resistant to cytotoxicity than autologous blood monocytes. PPD- plus IL-2-expanded AL and blood lymphocytes were cytotoxic for autologous mycobacterium-stimulated monocytes at E:T ratios of > or = 10:1. The CTL activity of lymphocytes expanded with PPD was predominantly class II MHC restricted, whereas the CTL activity of lymphocytes expanded with PPD plus IL-2 was both class I and class II MHC restricted. Both CD4+ and CD8+ T cells were enriched in BL and AL expanded with PPD and IL-2, and both subsets had mycobacterium-specific CTL activity. Such novel cytotoxic responses by CD4+ and CD8+ T cells may be a major mechanism of defense against MTB at the site of disease activity.

Characterization of CD4 and CD8 T cell responses in MuSK myasthenia gravis.

Muscle specific tyrosine kinase myasthenia gravis (MuSK MG) is a form of autoimmune MG that predominantly affects women and has unique clinical features, including prominent bulbar weakness, muscle atrophy, and excellent response to therapeutic plasma exchange. Patients with MuSK MG have predominantly IgG4 autoantibodies directed against MuSK on the postsynaptic muscle membrane. Lymphocyte functionality has not been reported in this condition. The goal of this study was to characterize T cell responses in patients with MuSK MG. Intracellular production of IFN-gamma, TNF-alpha, IL-2, IL-17, and IL-21 by CD4+ and CD8+ T cells was measured by polychromatic flow cytometry in peripheral blood samples from 11 Musk MG patients and 10 healthy controls. Only one MuSK MG patient was not receiving immunosuppressive therapy. Regulatory T cells (Treg) were also included in our analysis to determine if changes in T cell function were due to altered Treg frequencies. CD8+ T cells from MuSK MG patients had higher frequencies of polyfunctional responses than controls, and CD4+ T cells had higher IL-2, TNF-alpha, and IL-17. MuSK MG patients had a higher percentage of CD4+ T cells producing combinations of IFN-gamma/IL-2/TNF-gamma, TNF-alpha/IL-2, and IFN-gamma/TNF-alpha. Interestingly, Treg numbers and CD39 expression were not different from control values. MuSK MG patients had increased frequencies of Th1 and Th17 cytokines and were primed for polyfunctional proinflammatory responses that cannot be explained by a defect in CD39 expression or Treg number.

Increased rates of CD4+ and CD8+ T lymphocyte turnover in simian immunodeficiency virus-infected macaques

Defining the rate at which T cells turn over has important implications for our understanding of T lymphocyte homeostasis and AIDS pathogenesis, yet little information on T cell turnover is available. We used the nucleoside analogue bromodeoxyuridine (BrdUrd) in combination with five-color flow cytometric analysis to evaluate T lymphocyte turnover rates in normal and simian immunodeficiency virus (SIV)-infected rhesus macaques. T cells in normal animals turned over at relatively rapid rates, with memory cells turning over more quickly than naive cells. In SIV-infected animals, the labeling and elimination rates of both CD4+ and CD8+ BrdUrd-labeled cells were increased by 2- to 3-fold as compared with normal controls. In normal and SIV-infected animals, the rates of CD4+ T cell BrdUrd-labeling and decay were closely correlated with those of CD8+ T cells. The elimination rate of BrdUrd-labeled cells was accelerated in both naive and memory T lymphocytes in SIV-infected animals. Our results provide direct evidence for increased rates of both CD4+ and CD8+ T cell turnover in AIDS virus infection and have important implications for our understanding of T cell homeostasis and the mechanisms responsible for CD4+ T cell depletion in AIDS.

Cell surface Glut1 levels distinguish human CD4 and CD8 T lymphocyte subsets with distinct effector functions

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CD95 (FAS) and CD178 (FASL) induce the apoptosis of CD4+ and CD8+ cells isolated from the peripheral blood and spleen of dogs naturally infected with Leishmania spp

Infected dogs are urban reservoirs of Leishmania chagasi, which is a causative agent of visceral leishmaniasis (VL). Dogs exhibit immune suppression during the course of this disease, and lymphocyte apoptosis is involved in this process. To investigate apoptosis and the expression levels of FAS-FAS-associated death domain protein (CD95 or APO-1), FASL-FAS ligand protein (CD178), and TRAIL-TNF-related apoptosis-inducing ligand (CD253) receptors in peripheral blood mononuclear cells and spleen leukocytes from 38 symptomatic dogs with moderate VL and 25 healthy dogs were evaluated by flow cytometry. The apoptosis rate of blood and splenic CD4+ and CD8+ cells was higher in infected dogs than in healthy dogs. The expression levels of FAS and FASL in blood and splenic CD4+ cells were lower in infected dogs than in healthy dogs. FAS expression in CD8+ cells was higher in infected dogs than in healthy dogs; in contrast, FASL expression was lower in infected dogs. The expression of the TRAIL receptor increased only in splenic CD8+ cells from infected dogs. The FAS and FAS-L blocking antibodies confirmed the importance of these receptors in apoptosis. Our results enhance the current understanding of the immune response in dogs infected with L. chagasi, facilitating the future development of therapeutic interventions to reduce lymphocyte depletion. © 2013 Elsevier B.V.

CD95 (FAS) and CD178 (FASL) induce the apoptosis of CD4+ and CD8+ cells isolated from the peripheral blood and spleen of dogs naturally infected with Leishmania spp

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Intraperitoneal Echinococcus multilocularis infection in mice modulates peritoneal CD4+ and CD8+ regulatory T cell development

Intraperitoneal proliferation of the metacestode stage of Echinococcus multilocularis in experimentally infected mice is followed by an impaired host immune response favoring parasite survival. We here demonstrate that infection in chronically infected mice was associated with a 3-fold increase of the percentages of CD4+ and CD8+ peritoneal T (pT) cells compared to uninfected controls. pT cells of infected mice expressed high levels of IL-4 mRNA, while only low amounts of IFN-gamma mRNA were detected, suggesting that a Th2-biased immune response predominated the late stage of disease. Peritoneal dendritic cells from infected mice (AE-pDCs) expressed high levels of TGF-beta mRNA and very low levels of IL-10 and IL-12 (p40) mRNA, and the expression of surface markers for DC-maturation such as MHC class II (Ia) molecules, CD80, CD86 and CD40 was down-regulated. In contrast to pDCs from non-infected mice, AE-pDCs did not enhance Concanavalin A (ConA)-induced proliferation when added to CD4+ pT and CD8+ pT cells of infected and non-infected mice, respectively. In addition, in the presence of a constant number of pDCs from non-infected mice, the proliferation of CD4+ pT cells obtained from infected animals to stimulation with ConA was lower when compared to the responses of CD4+ pT cells obtained from non-infected mice. This indicated that regulatory T cells (Treg) may interfere in the complex immunological host response to infection. Indeed, a subpopulation of regulatory CD4+ CD25+ pT cells isolated from E. multilocularis-infected mice reduced ConA-driven proliferation of CD4+ pT cells. The high expression levels of Foxp3 mRNA by CD4+ and CD8+ pT cells suggested that subpopulations of regulatory CD4+ Foxp3+ and CD8+ Foxp3+ T cells were involved in modulating the immune responses within the peritoneal cavity of E. multilocularis-infected mice.

Analysis of the effect of different NKT cell subpopulations on the activation of CD4 and CD8 T cells, NK cells, and B cells

Objective. NKT cells have diverse immune regulatory functions including activation of cells involved in Th1- and Th2-type immune activities. Most previous studies have investigated the functions of NKT cells as a single family but more recent evidence indicates the distinct functional properties of NKT cell subpopulation. This study aims to determine whether NKT cell subpopulations have different stimulatory activities on other immune cells that may affect the outcome of NKT cell-based immunotherapy. Methods. NKT cells and NKT cell subpopulations (CD4(+)CD8(-), CD4(-)CD8(+), CD4(-)CD8(+)) were cocultured with PBMC and their activities on immune cells including CD4(+) and CD8(+) T cells, NK cells, and B cells were assessed by flow cytometry. The production of cytokines in culture was measured by enzyme-linked immunsorbent assay. Results. The CD4(+)CD8(-) NKT cells demonstrated substantially greater stimulatory activities on CD4(+) T cells, NK cells, and B cells than other NKT cell subsets. The CD4(-)CD8(+) NKT cells showed the greatest activity on CD8(+) T cells, and were the only NKT cell subset that activated these immune cells. The CD4(-)CD8(-) NKT cells showed moderate stimulatory activity on CD4(+) T cells and the least activity on other immune cells. Conclusion. The results here suggest that NKT cell subpopulations differ in their abilities to stimulate other immune cells. This highlights the potential importance of manipulating specific NKT cell subpopulations for particular therapeutic situations and of evaluating subpopulations, rather than NKT cells as a group, during investigation of a possible role of NKT cells in various disease settings. (c) 2006 International Society for Experimental Hematology. Published by Elsevier Inc.

The role of CD4(+) and CD8(+) T cells on antibody production by murine Peyer's patch cells following mucosal presentation of Actinomyces viscosus

The aim of this study was to determine the role of CD4 and CD8 cells on specific antibody production by murine Peyer's patch (PP) cells after oral immunization with Actinomyces viscosus in mice. Female DBA/2 mice were orally immunized with three low doses of heat-killed A. viscosus. Sham-immunized mice served as a control group. Mice were depleted of CD4 or CD8 cells by intraperitoneal injection of anti-CD4 or anti-CD8 antibodies daily for 3 days before oral immunization. One week after the last oral immunization, PPs were removed and cell suspensions were cultured with A. viscosus. Specific antibody production in the culture supernatants was assessed by enzyme-linked immunosorbent assay. The results showed that oral immunization with A. viscosus induced a predominant specific immunoglobulin A (IgA) response by PP cells and, to a lesser extent, IgM antibodies. Depletion of CD4 but not CD8 cells suppressed the production of specific antibodies. These results suggest that oral immunization with low doses of A. viscosus may induce the production of specific antibodies by murine PP cells in a CD4-cell-dependent fashion.

CD95 (FAS) e CD178 (FASL) induzem apoptose em células CD4+ E CD8+ do sangue periférico e esplênicas em cães naturalmente infectados por Leishmania spp: Kathlenn Liezbeth Oliveira Silva. -

Pós-graduação em Ciência Animal - FMVA

Imunimarcação de subpopulações de linfócitos CD3+, CD4+ e CD8 associada à expressão de metaloproteinases -2 e -9 em cerebelos de cães infectados naturalmente com vírus da cinomose canina

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)