scholarly journals Expression Dynamics of the O-Glycosylated Proteins Recognized by Amaranthus leucocarpus Lectin in T Lymphocytes and Its Relationship With Moesin as an Alternative Mechanism of Cell Activation

2021 ◽  
Vol 12 ◽  
Author(s):  
Wilton Gómez-Henao ◽  
Rafael Saavedra ◽  
Francisco Raúl Chávez-Sánchez ◽  
Ricardo Lascurain ◽  
Edgar Zenteno ◽  
...  
Keyword(s):  
T Cell ◽  
T Lymphocytes ◽  
T Cell Activation ◽  
Cell Activation ◽  
Costimulatory Molecule ◽  
Lymphocyte Activation ◽  
T Cell Subsets ◽  
Alternative Mechanism ◽  
Amaranthus Leucocarpus

T lymphocyte activation begins with antigen/MHC recognition by the TCR/CD3 complex followed by a costimulatory signal provided by CD28. The search for novel costimulatory molecules has been extensive due to their potential use as immunotherapeutic targets. Although some molecules have been identified, they are unable to provide sustainable signaling to allow for proper T cell activation and proliferation. It has been shown that the Amaranthus leucocarpus lectin (ALL) can be used as an in vitro costimulator of CD4+ lymphocytes in the presence of anti-CD3 mAb; this lectin specifically recognizes O-glycans of the Galβ1-3GalNAc-O-Ser/Thr type, including a 70-kDa moesin-like protein that has been suggested as the costimulatory molecule. However, the identity of this molecule has not been confirmed and such costimulation has not been analyzed in CD8+ lymphocytes. We show herein that the expression kinetics of the glycoproteins recognized by ALL (gpALL) is different in CD4+ and CD8+ T cells, unlike moesin expression. Results from IP experiments demonstrate that the previously described 70-kDa moesin-like protein is an O-glycosylated form of moesin (O-moesin) and that in vitro stimulation with anti-CD3 and anti-moesin mAb induces expression of the activation molecules CD69 and CD25, proliferation and IL-2 production as efficiently as cells costimulated with ALL or anti-CD28. Overall, our results demonstrate that O-moesin is expressed in CD4+ and CD8+ T lymphocytes and that moesin provides a new costimulatory activation signal in both T cell subsets.

scholarly journals Immune function of the blood-brain barrier: incomplete presentation of protein (auto-)antigens by rat brain microvascular endothelium in vitro.

1990 ◽  
Vol 110 (5) ◽  
pp. 1757-1766 ◽  
Author(s):  
W Risau ◽  
B Engelhardt ◽  
H Wekerle
Keyword(s):  
T Cells ◽  
Endothelial Cells ◽  
T Cell ◽  
T Lymphocytes ◽  
Rat Brain ◽  
Blood Brain Barrier ◽  
T Cell Activation ◽  
Cell Activation ◽  
Ifn Gamma

The endothelial blood-brain barrier (BBB) has a critical role in controlling lymphocyte traffic into the central nervous system (CNS), both in physiological immunosurveillance, and in its pathological aberrations. The intercellular signals that possibly could induce lymphocytes to cross the BBB include immunogenic presentation of protein (auto-)antigens by BBB endothelia to circulating T lymphocytes. This concept has raised much, though controversial, attention. We approached this problem by analyzing in vitro immunospecific interactions between clonal rat T lymphocyte lines with syngeneic, stringently purified endothelial monolayer cultures from adult brain micro-vessels. The rat brain endothelia (RBE) were established from rat brain capillaries using double collagenase digestion, density gradient fractionation and selective cytolysis of contaminating pericytes by anti-Thy 1.1 antibodies and complement. Incubation with interferon-gamma in most of the brain-derived endothelial cells induced Ia-antigens in the cytoplasm and on the cell surface in some of the cells. Before the treatment, the cells were completely Ia-negative. Pericytes were unresponsive to IFN-gamma treatment. When confronted with syngeneic T cell lines specific for protein (auto-)antigens (e.g., ovalbumin and myelin basic protein, MBP), RBE were completely unable to induce antigen-specific proliferation of syngeneic T lymphocytes irrespective of pretreatment with IFN-gamma and of cell density. RBE were inert towards the T cells, and did not suppress T cell activation induced by other "professional" antigen presenting cells (APC) such as thymus-derived dendritic cells or macrophages. IFN-gamma-treated RBE were, however, susceptible to immunospecific T cell killing. They were lysed by MBP-specific T cells in the presence of the specific antigen or Con A. Antigen dependent lysis was restricted by the appropriate (MHC) class II product. We conclude that the interaction of brain endothelial cells with encephalitogenic T lymphocytes may involve recognition of antigen in the molecular context of relevant MHC products, but that this interaction per se is insufficient to initiate the full T cell activation program.

scholarly journals Condensation of the plasma membrane at the site of T lymphocyte activation

2005 ◽  
Vol 171 (1) ◽  
pp. 121-131 ◽  
Author(s):  
Katharina Gaus ◽  
Elena Chklovskaia ◽  
Barbara Fazekas de St. Groth ◽  
Wendy Jessup ◽  
Thomas Harder
Keyword(s):  
Plasma Membrane ◽  
T Cell ◽  
T Lymphocytes ◽  
T Cell Activation ◽  
Cell Activation ◽  
Transmembrane Protein ◽  
Lymphocyte Activation ◽  
Cell Receptor ◽  
Membrane Domains ◽  
Tcr Signaling

After activation, T lymphocytes restructure their cell surface to form membrane domains at T cell receptor (TCR)–signaling foci and immunological synapses (ISs). To address whether these rearrangements involve alteration in the structure of the plasma membrane bilayer, we used the fluorescent probe Laurdan to visualize its lipid order. We observed a condensation of the plasma membrane at TCR activation sites. The formation of ordered domains depends on the presence of the transmembrane protein linker for the activation of T cells and Src kinase activity. Moreover, these ordered domains are stabilized by the actin cytoskeleton. Membrane condensation occurs upon TCR stimulation alone but is prolonged by CD28 costimulation with TCR. In ISs, which are formed by conjugates of TCR transgenic T lymphocytes and cognate antigen-presenting cells, similar condensed membrane phases form first in central regions and later at the periphery of synapses. The formation of condensed membrane domains at T cell activation sites biophysically reflects membrane raft accumulation, which has potential implications for signaling at ISs.

scholarly journals CD28 interaction with B7 costimulates primary allogeneic proliferative responses and cytotoxicity mediated by small, resting T lymphocytes.

1992 ◽  
Vol 175 (2) ◽  
pp. 353-360 ◽  
Author(s):  
M Azuma ◽  
M Cayabyab ◽  
D Buck ◽  
J H Phillips ◽  
L L Lanier
Keyword(s):  
T Cells ◽  
T Cell ◽  
T Lymphocytes ◽  
T Cell Activation ◽  
Proliferative Response ◽  
Cell Activation ◽  
B Cell Activation ◽  
Rapid Responses ◽  
Cell Clones

Engagement of the CD3/T cell antigen receptor complex on small, resting T cells is insufficient to trigger cell-mediated cytotoxicity or to induce a proliferative response. In the present study, we have used genetic transfection to demonstrate that interaction of the B7-BB1 B cell activation antigen with the CD28 T cell differentiation antigen costimulates cell-mediated cytotoxicity and proliferation initiated by either anti-CD2 or anti-CD3 monoclonal antibody (mAb). Moreover, a B7-negative Burkitt's lymphoma cell line that fails to stimulate an allogeneic mixed lymphocyte response is rendered a potent stimulator after transfection with B7. The mixed leukocyte reaction proliferative response against the B7 transfectant is inhibited by either anti-CD28 or B7 mAb. We also demonstrate that freshly isolated small, resting human T cells can mediate anti-CD3 or anti-CD2 mAb-redirected cytotoxicity against a murine Fc receptor-bearing mastocytoma transfected with human B7. These preexisting cytotoxic T lymphocytes in peripheral blood are present in both the CD4 and CD8 subsets, but are preferentially within the CD45RO+ "memory" population. While small, resting T cells apparently require costimulation by CD28/B7 interactions, this requirement is lost after T cell activation. Anti-CD3 initiates a cytotoxic response mediated by in vitro cultured T cell clones in the absence of B7 ligand. The existence of functional cytolytic T cells in the small, resting T cell population may be advantageous in facilitating rapid responses to immune challenge.

scholarly journals Voriconazole Inhibits Fungal Growth without Impairing Antigen Presentation or T-Cell Activation

2003 ◽  
Vol 47 (6) ◽  
pp. 1818-1823 ◽  
Author(s):  
Heather L. Van Epps ◽  
Marta Feldmesser ◽  
Eric G. Pamer
Keyword(s):  
T Cells ◽  
T Cell ◽  
T Lymphocytes ◽  
Animal Models ◽  
T Cell Activation ◽  
Cell Activation ◽  
Fungal Growth ◽  
Antifungal Drugs ◽  
Isolation And Characterization

ABSTRACT Invasive aspergillosis (IA) is the most common life-threatening invasive mold infection worldwide. The principal therapy for IA is amphotericin B, despite its known toxicity and immunosuppressive side effects. Studies in animal models of IA suggest a role for T lymphocytes in the pathology of the disease, although the precise role for Aspergillus-specific T cells remains undefined. The isolation and characterization of T lymphocytes in animal models of IA are hampered by the rapid outgrowth of the fungus in cultures derived from infected organs. In the present study, we tested the abilities of the antifungal drugs caspofungin acetate and voriconazole to inhibit fungal growth in vitro as a means of maintaining cultures of T cells from Aspergillus-infected mice. We demonstrate that while both antifungal drugs are inhibitory, only voriconazole completely inhibited fungal growth, allowing long-term maintenance of T-cell cultures. In addition, voriconazole had no inhibitory effect on the activation and maturation of dendritic cells or the proliferation of T lymphocytes. Thus, voriconazole appears to be a promising agent for use in in vitro studies of Aspergillus-specific T lymphocytes in animal models of IA.

scholarly journals Causes of T lymphocyte activation in HIV-infected patients coinfected with hepatitis C virus

2016 ◽  
Vol 88 (11) ◽  
pp. 22-28
Author(s):  
K V Shmagel ◽  
N G Shmagel ◽  
L B Korolevskaya ◽  
E V Saydakova ◽  
V A Chereshnev
Keyword(s):  
T Cells ◽  
Hepatitis C ◽  
T Cell ◽  
T Lymphocytes ◽  
T Cell Activation ◽  
T Lymphocyte ◽  
Cell Activation ◽  
Lymphocyte Activation ◽  
Cd8 T Cell ◽  
Cd8 T Lymphocytes

Aim. To establish the causes of T lymphocyte activation in human immunodeficiency virus (HIV)-infected patients coinfected with hepatitis C (HCV) who are adherent to their antiretroviral therapy regimen and interferon untreated. Subjects and methods. Examinations were made in 62 people who were HIV+HCV-positive (n=21), HIV+HCV-negative (n=21), and noninfected volunteers (n=20). The activation (CD38+HLA-DR+) and proliferation (Ki-67+) of CD4+ and CD8+ T lymphocytes were estimated. The blood concentration of intestinal fatty acid-binding protein (I-FABP) was determined. Results. The proportion of activated cells among the CD4+ T lymphocytes was equal in the HIV+HCV-positive and HIV+HCV-negative groups. But these indicators were statistically significantly higher than those in the controls (HIV- HCV-). CD8+ T cell activation was greater in the HIV/HCV-coinfected patients than that in the other groups and that was higher in the HIV monoinfected than in the noninfected. The blood I-FABP concentrations were elevated in the HIV+HCV-positive and HIV+HCV groups compared with those in the HIV-HCV-negative group, but these did not differ among themselves. In the HIV+HCV-negative patients, CD4+ and CD8+ T cell activation directly and statistically significantly correlated with blood I-FABP levels. In the HIV+HCV-positive group, this correlation remained only for CD4+ T lymphocytes. CD8+ T cell activation in HIV/HCV-coinfected patients was unrelated to I-FABP concentrations. Conclusion. The increased activation of CD4+ and CD8+ T lymphocytes in HIV monoinfection was found to be associated with intestinal epithelial destruction and unrelated to cell division processes. In HIV/HCV coinfection, the activated state of CD4+ T cells is determined by both the level of proliferative processes and impairment of the intestinal barrier and that of CD8+ T cells is only by proliferation.

scholarly journals The Expression of CD28 and Its Synergism on the Immune Response of Flounder (Paralichthys olivaceus) to Thymus-Dependent Antigen

2021 ◽  
Vol 12 ◽  
Author(s):  
Jing Xing ◽  
Wenjing Liu ◽  
Xiaoqian Tang ◽  
Xiuzhen Sheng ◽  
Heng Chi ◽  
...  
Keyword(s):  
T Cell ◽  
T Lymphocytes ◽  
T Cell Activation ◽  
Cell Activation ◽  
Expression Profiles ◽  
Paralichthys Olivaceus ◽  
Control Group ◽  
Cd28 Molecule ◽  
Costimulatory Pathway

CD28 is well known as a critical T-cell costimulatory receptor involved in T cell activation by binding to its ligands. In this study, CD28 was cloned, and its expression profiles were characterized in flounder (Paralichthys olivaceus); variations of CD28+ cells after being stimulated with different types of antigens and the function of the CD28 costimulatory pathway on T-cell activation were investigated in vitro. fCD28 consists of four exons and three introns, and the full-length cDNA of fCD28 was 675-bp encoded 224 amino acids. The conserved motif (121TFPPPF126) binding to the CD80/86 ligand exists in the Ig-superfamily homology domain. The high expression of fCD28 is in gills, PBLs, head kidney, and spleen. CD28+ cells were co-localized with CD4+ T lymphocytes but not on IgM+ B lymphocyte cells. Moreover, the expression of CD28 was significantly varied in flounder after being stimulated by keyhole limpet hemocyanin (KLH) at both the transcriptional and cellular levels, while no significant differences were observed between lipopolysaccharide (LPS) stimulation and the control group. Notably, treatment of PBLs cultured in vitro with CD28 molecule-specific antibody (anti-CD28 Abs) and PHA produced more cell colonies and stimulated the proliferation of cultured leukocytes compared to PHA stimulation alone and the control group, and a higher level of IL-2 was detected in the culture medium. Meanwhile, anti-CD28 Abs increased the percent of CD28+ cells (10.41 ± 1.35%), CD4+ T lymphocytes (18.32 ± 2.15%), and CD28+/CD4+ double-positive cells (6.24 ± 1.52%). This effect also resulted in significant variations in the genes of cell membrane-bound molecules, cytokines, and related signaling pathways in cultured leukocytes, with significant changes in the genes of interleukin-2 (IL-2) and nuclear factor of activated T cells (NFAT) in the early stages of culture, and the expression of other molecules increased over time. These results proved the localization of the CD28 molecule on T lymphocytes in flounder, and anti-CD28 may act as the B7 ligand involved in T cell activation after antigen stimulation. These data provide a basis for a more in-depth study of the mechanism of the CD28 costimulatory pathway in T cell activation.

scholarly journals CD4+ICOS+ T lymphocytes inhibit T cell activation ‘in vitro’ and attenuate autoimmune encephalitis ‘in vivo’

2008 ◽  
Vol 20 (4) ◽  
pp. 577-589 ◽  
Author(s):  
Jose M. Rojo ◽  
Eliana Pini ◽  
Gloria Ojeda ◽  
Raquel Bello ◽  
Chen Dong ◽  
...  
Keyword(s):  
T Cell ◽  
T Lymphocytes ◽  
T Cell Activation ◽  
Cell Activation ◽  
Autoimmune Encephalitis

Interaction of Human Mesenchymal Stem Cells with Alloantigen-Induced T Lymphocyte Activation Favors the Differentiation of CD4+ T Cell Subsets Expressing CD25 and/or CTLA4 Molecules.

Blood ◽  
2004 ◽  
Vol 104 (11) ◽  
pp. 2123-2123
Author(s):  
Rita Maccario ◽  
Marina Podestà ◽  
Antonia Moretta ◽  
Angela Cometa ◽  
Patrizia Comoli ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
T Cell Activation ◽  
Cell Activation ◽  
Human Mesenchymal Stem Cells ◽  
Lymphocyte Activation ◽  
Third Party ◽  
T Cell Subsets ◽  
Cd4 T Cell ◽  
Dose Dependent

Abstract Experimental evidence and preliminary clinical studies have demonstrated that human mesenchymal stem cells (MSCs) display important immune modulatory function of potential relevant interest in the setting of allogeneic hematopoietic stem cell (HSC) transplantation. Effectiveness of MSCs in controlling severe GVHD seems to be related to the immune-regulatory role they play in suppressing alloantigen-specific T-cell activation. Aim of the present study was to extend the analysis of the mechanisms responsible for the immune regulatory effect of interaction between MSCs and alloantigen-specific immune response elicited in vitro in primary and in secondary mixed lymphocyte culture (MLC). At difference with most previously reported studies, we decided to employ non-irradiated MSCs, reasoning that irradiation might impair, beside the proliferative capacity, also the differentiation capability of MSCs and, consequently, alter their interaction pattern with lymphocyte subsets. MSC were added to primary MLC at different doses (MLC-responder-PBMC:MSC ratios = 1:1 and 10:1). Dendritic cell (DC) differentiation, lymphocyte proliferation, alloantigen-specific cytotoxic activity and differentiation of CD4+ T-cell subsets expressing CD25 and/or CTLA4 antigens were assessed in primary and secondary MLC, comparing the effect observed using third-party MSCs with that obtained employing autologous to the MLC-responder (autologous) MSCs. Results demonstrated that human MSCs: (1) strongly inhibit alloantigen-induced DC1 differentiation; (2) down-regulate, in a dose-dependent manner, alloantigen-induced lymphocyte expansion, especially that of CD8+ T cells and of NK lymphocytes; (3) favor the differentiation of CD4+ T cells co-expressing CD25 and/or CTLA4, a phenotype associated with regulatory/suppressive function of immune response; (4) cause a dose-dependent reduction of alloantigen-specific cytotoxic capacity mediated by either cytotoxic T lymphocytes or NK cells; (5) exert more effective suppressive activity on MLC-induced T-cell activation when they are allogeneic rather than autologous with respect to responder cells. In particular, higher percentages of CD4+ and of CD4+CD25+ T cells co-expressing CTLA4+ were detected when third-party, rather than autologous, MSCs were added to MLC. These data suggest that T-cell recognition of alloantigens expressed by MSCs may further facilitate the preferential differentiation of activated CD4+ T cells expressing CTLA4, a glycoprotein, known to deliver an inhibitory signal to T cells and to mediate apoptosis of previously activated T lymphocytes. Several studies previously demonstrated that MSCs exert inhibitory effect on lymphocyte activation through the release of soluble factors. Our data suggest that the preferential differentiation of CD4+CD25+ regulatory T-cell subsets may be favored by other mechanisms of MSC-mediated inhibition of alloantigen-induced effector cell activation and expansion, and, in turn, these CD4+CD25+ cells contribute to propagate and extend suppressor activity. Altogether, our results provide immunological support to the use of MSCs for prevention of immune complications related to both HSC and solid organ transplantation and to the theory that MSCs are “universal” suppressors of immune reactivity.

scholarly journals Natural inhibitors of T-cell activation in Hodgkin's disease

Blood ◽  
1991 ◽  
Vol 78 (9) ◽  
pp. 2365-2371 ◽  
Author(s):  
M Roux ◽  
B Schraven ◽  
A Roux ◽  
H Gamm ◽  
R Mertelsmann ◽  
...  
Keyword(s):  
T Cell ◽  
T Lymphocytes ◽  
T Cell Activation ◽  
Hodgkin's Disease ◽  
Cell Activation ◽  
Cell Function ◽  
Hodgkin’S Disease ◽  
Alternative Pathway ◽  
Cellular Level

Abstract Secondary immunodeficiency is frequently observed in Hodgkin's disease (HD) and is due in part to impaired T-cell function. Using monoclonal antibodies that bind to triggering molecules of human T lymphocytes (CD3/Ti antigen receptor; CD2 E-rosette receptor) and exert functional effects on T-cell activation, we have investigated in vitro immune responses of circulating lymphocytes from patients with HD in progression (n = 9) and in remission (n = 14). In patients with progressive HD, a severe dysfunction of the alternative CD2-mediated T- cell activation pathway was detected (49.3 +/- 14.2 v 9.4 +/- 5.1 cpm x 10(-3), in controls, P less than .01; n = 9) that parallels the reduced capacity of T lymphocytes to form rosettes with sheep red blood cells. Diminished alternative pathway activation in HD is not only due to a defect at the cellular level but also due to soluble mediators in the patients' plasma. Plasma from patients in progression markedly reduces CD2 mediated activation (P less than .01). These activities interfere, at least in part, with CD2/CD58 interactions and, therefore, reduce T- lymphocyte triggering through this amplifier mechanism.

scholarly journals The association between CD28 gene rs3116496 polymorphism and breast cancer risk in Chinese women

2017 ◽  
Vol 37 (6) ◽  
Author(s):  
Yuxiang Yan ◽  
Xianbo Zhang
Keyword(s):  
Breast Cancer ◽  
T Cell ◽  
T Cell Activation ◽  
Cell Activation ◽  
Mrna Level ◽  
Costimulatory Molecule ◽  
Lymphocyte Activation ◽  
Chinese Han ◽  
Bioinformatics Analyses ◽  
Increased Risk

T-lymphocyte activation plays an important role in suppressing the development of human cancers including breast cancer (BC). Cluster of differentiation 28 (CD28) is the primary T-cell costimulatory molecule and enhances T-cell activation and proliferation. To examine the role of CD28 gene polymorphism in BC, we conducted a case–control study involving 312 BC patients and 312 controls in a Chinese Han population. Bioinformatics analyses were conducted to analyze the expression level of CD28 and its association with overall survival (OS) of BC. Genotyping was performed using a custom-by-design 48-Plex single nucleotide polymorphism (SNP) Scan™ Kit. Our results indicated that CD28 mRNA level was down-regulated in the BC patients, whereas high expression of CD28 showed better OS for BC. In addition, an increased risk of BC was associated with the rs3116496 CC genotype of CD28 gene (CC vs. TT). The significant association was also observed in the recessive model. In conclusion, CD28 may be a tumor suppressor gene and rs3116496 polymorphism of CD28 gene showed positively correlation with the increased risk of BC. However, larger studies with more diverse ethnic populations are needed to confirm these results.

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