The Experts below are selected from a list of 69 Experts worldwide ranked by ideXlab platform

Anis Larbi - One of the best experts on this subject based on the ideXlab platform.

  • CD57 in human natural killer cells and T-lymphocytes
    Cancer Immunology Immunotherapy, 2016
    Co-Authors: Hassen Kared, Serena Martelli, Tze Pin Ng, Sylvia L.f. Pender, Anis Larbi
    Abstract:

    The CD57 Antigen (alternatively HNK-1, LEU-7, or L2) is routinely used to identify terminally differentiated ‘senescent’ cells with reduced proliferative capacity and altered functional properties. In this article, we review current understanding of the attributes of CD57-expressing T-cells and NK cells in both health and disease and discuss how this marker can inform researchers about their likely functions in human blood and tissues in vivo. While CD57 expression on human lymphocytes indicates an inability to proliferate, these cells also display high cytotoxic potential, and CD57^pos NK cells exhibit both memory-like features and potent effector functions. Accordingly, frequencies of CD57-expressing cells in blood and tissues have been correlated with clinical prognosis in chronic infections or various cancers and with human aging. Functional modulation of senescent CD57^pos T-cells and mature CD57^pos NK cells may therefore represent innovative strategies for protection against human immunological aging and/or various chronic diseases.

Hassen Kared - One of the best experts on this subject based on the ideXlab platform.

  • CD57 in human natural killer cells and T-lymphocytes
    Cancer Immunology Immunotherapy, 2016
    Co-Authors: Hassen Kared, Serena Martelli, Tze Pin Ng, Sylvia L.f. Pender, Anis Larbi
    Abstract:

    The CD57 Antigen (alternatively HNK-1, LEU-7, or L2) is routinely used to identify terminally differentiated ‘senescent’ cells with reduced proliferative capacity and altered functional properties. In this article, we review current understanding of the attributes of CD57-expressing T-cells and NK cells in both health and disease and discuss how this marker can inform researchers about their likely functions in human blood and tissues in vivo. While CD57 expression on human lymphocytes indicates an inability to proliferate, these cells also display high cytotoxic potential, and CD57^pos NK cells exhibit both memory-like features and potent effector functions. Accordingly, frequencies of CD57-expressing cells in blood and tissues have been correlated with clinical prognosis in chronic infections or various cancers and with human aging. Functional modulation of senescent CD57^pos T-cells and mature CD57^pos NK cells may therefore represent innovative strategies for protection against human immunological aging and/or various chronic diseases.

Léon J. Simar - One of the best experts on this subject based on the ideXlab platform.

  • Germinal Center T Cells: Analysis of Their Proliferative Capacity
    Advances in Experimental Medicine and Biology, 1995
    Co-Authors: F. Bouzahzah, A. Bosseloir, Ernst Heinen, Léon J. Simar
    Abstract:

    Several immunohistochemical studies have revealed the existence of T cells expressing the CD57 Antigen in the germinal center1. A few are also found in the interfollicular zones and the mantle zone2. Phenotypically they are CD4+, CD8- cells. They do not express Leu8, CD16 or CDllb3,4,5. These cells are not fully activated being CD25-,CD71- and HLA-DR- cells6.

  • Human germinal center CD4+CD57+ T cells act differently on B cells than do classical T-helper cells.
    Developmental Immunology, 1995
    Co-Authors: F. Bouzahzah, A. Bosseloir, Ernst Heinen, Léon J. Simar
    Abstract:

    We have isolated two subtypes of helper T cells from human tonsils: CD4+ CD57+ cells, mostly located in the germinal center (GC), and CD4+ CD57- cells, distributed through the interfollicular areas but also present in the GC. In a functional study, we have compared the capacities of these T-cell subtypes to stimulate B cells in cocultures. In order to block T-cell proliferation while maintaining their activation level, we pretreated isolated T cells with mitomycin C prior to culture in the presence of B cells and added polyclonal activators such as PHA and Con A, combined or not with IL-2. Contrary to CD4+ CD57- cells, CD4+ CD57+ cells did not markedly enhance B-cell proliferation. Even when sIgD-B cells typical of germinal center cells were tested, the CD4 CD57 cells had no significant effect. This is in accordance with the location of these cells: They mainly occupy the light zones of the GC where few B cells divide. Even when added to preactivated, actively proliferating cells, CD4+ CD57+ cells failed to modulate B-cell multiplication. On the supernatants of B-cell-T-cell cocultures, we examined by the ELISA technique the effect of T cells on Ig synthesis. Contrary to CD57- T cells, whose effect was strong, CD57+ T cells weakly stimulated Ig synthesis. More IgM than IgG was generally found. Because CD57 Antigen is a typical marker of natural killer cells, we tested the cytolytic activity of tonsillar CD4+ CD57+ cells on K562 target cells. Unlike NK cells, neither CD4+CD57+ nor CD4+ CD57- cells exhibit any cytotoxicity. Thus, germinal center CD4+ CD57+ cells are not cytolytic and do not strongly stimulate either B-cell proliferation or Ig secretion. CD4+ CD57- cells, however, enhance B-cell proliferation and differentiation, thus acting like the classical helper cells of the T-dependent areas.

  • Ultrastructure of CD57+ cells isolated from human tonsils or blood.
    European Journal of Morphology, 1993
    Co-Authors: F. Bouzahzah, A. Bosseloir, Ernst Heinen, Nadine Antoine, I. Mancini, Léon J. Simar
    Abstract:

    : The presence of CD4+, CD57+ T cells in the germinal centers has been reported by several authors. The CD57 Antigen is also expressed by natural killer (NK) cells. We purified CD57+ cells from human tonsils and blood by microdissection, rosetting with sheep red blood cells and magnetic cell sorting (MACS) and examined the ultrastructural morphology of these cells. Clear differences were found in cell aspect: blood NK contained large granules which were not found in the tonsillar CD57+ cells. These latter appeared medium-sized and not fully activated. After immunolabeling, the tonsillar CD57+ cells were mainly found in the light zone of the germinal centers.

J. M. Urra - One of the best experts on this subject based on the ideXlab platform.

  • Decreased Expression of the CD57 Molecule in T Lymphocytes of Patients with Chronic Fatigue Syndrome
    Molecular Neurobiology, 2019
    Co-Authors: P. Espinosa, J. M. Urra
    Abstract:

    The chronic fatigue syndrome (CFS) is characterized by a prolonged incapacitating fatigue, headaches, sleep disturbances, and decreases in cognition, besides alterations in other physiological functions. At present, no specific biological markers have been described in this pathology. In the present study, we analyzed in lymphocytes the CD57 expression for the diagnosis of CFS, evaluating both the percentage of blood lymphocytes expressing CD57 and the average amount of the molecule expressed per cell. The study demonstrated a marked and significant decrease in the expression of CD57 in lymphocytes of CFS patients regarding healthy controls. In T lymphocytes, the decrease was significant both in the percentage of cells expressing CD57 (7.5 ± 1.2 vs 13.3 ± 1.6, p  = 0.024) and in a more relevant way in the amount of CD57 molecule expressed per cell (331 ± 59 vs 1003 ± 104, p  ≤ 0.0001). In non-T lymphocytes, the decrease was significant only in the amount of CD57 expressed per cell (379 ± 114 vs 691 ± 95, p  = 0.007). The study of CD57 Antigen in blood lymphocytes is a useful marker that could cooperate in the diagnosis of CFS patients. Its decrease in T lymphocytes provides most valuable results than the results in other lymphocyte subpopulations.

F. Bouzahzah - One of the best experts on this subject based on the ideXlab platform.

  • Germinal Center T Cells: Analysis of Their Proliferative Capacity
    Advances in Experimental Medicine and Biology, 1995
    Co-Authors: F. Bouzahzah, A. Bosseloir, Ernst Heinen, Léon J. Simar
    Abstract:

    Several immunohistochemical studies have revealed the existence of T cells expressing the CD57 Antigen in the germinal center1. A few are also found in the interfollicular zones and the mantle zone2. Phenotypically they are CD4+, CD8- cells. They do not express Leu8, CD16 or CDllb3,4,5. These cells are not fully activated being CD25-,CD71- and HLA-DR- cells6.

  • Differently On B Cells Than Do Classical T-Helper Cells
    1995
    Co-Authors: F. Bouzahzah, A. Bosseloir, Ernst Heinen, J. Simar
    Abstract:

    We have isolated two subtypes of helper T cells from human tonsils: CD4 CD57 cells, mostly located in the germinal center (GC), and CD4 CD57- cells, distributed through the interfollicular areas but also present in the GC. In a functional study, we have compared the capacities of these T-cell subtypes to stimulate B cells in cocultures. In order to block T-cell proliferation while maintaining their activation level, we pretreated isolated T cells with mitomycin C prior to culture in the presence of B cells and added polyclonal activators such as PHA and Con A, combined or not with IL-2. Contrary to CD4/CD57- cells, CD4 CD57 cells did not markedly enhance B-cell proliferation. Even when sIgD-B cells typical of germinal center cells were tested, the CD4 CD57 cells had no significant effect. This is in accordance with the location of these cells: They mainly occupy the light zones of the GC where few B cells divide. Even when added to preactivated, actively proliferating cells, CD4 CD57 cells failed to modulate B-cell multiplication. On the supernatants of B-cell-T-cell cocultures, we examined by the ELISA technique the effect of T cells on Ig synthesis. Contrary to CD57- T cells, whose effect was strong, CD57 T cells weakly stimulated Ig synthesis. More IgM than IgG was generally found. Because CD57 Antigen is a typical marker of natural killer cells, we tested the cytolytic activity of tonsillar CD4/CD57 cells on K562 target cells. Unlike NK cells, neither CD4+CD57 nor CD4 CD57- cells exhibit any cytotoxicity. Thus, germinal center CD4 CD57 cells are not cytolytic and do not strongly stimulate either B-cell proliferation or Ig secretion. CD4 CD57- cells, however, enhance B-cell proliferation and differentiation, thus acting like the classical helper cells of the T-dependent areas.

  • Human germinal center CD4+CD57+ T cells act differently on B cells than do classical T-helper cells.
    Developmental Immunology, 1995
    Co-Authors: F. Bouzahzah, A. Bosseloir, Ernst Heinen, Léon J. Simar
    Abstract:

    We have isolated two subtypes of helper T cells from human tonsils: CD4+ CD57+ cells, mostly located in the germinal center (GC), and CD4+ CD57- cells, distributed through the interfollicular areas but also present in the GC. In a functional study, we have compared the capacities of these T-cell subtypes to stimulate B cells in cocultures. In order to block T-cell proliferation while maintaining their activation level, we pretreated isolated T cells with mitomycin C prior to culture in the presence of B cells and added polyclonal activators such as PHA and Con A, combined or not with IL-2. Contrary to CD4+ CD57- cells, CD4+ CD57+ cells did not markedly enhance B-cell proliferation. Even when sIgD-B cells typical of germinal center cells were tested, the CD4 CD57 cells had no significant effect. This is in accordance with the location of these cells: They mainly occupy the light zones of the GC where few B cells divide. Even when added to preactivated, actively proliferating cells, CD4+ CD57+ cells failed to modulate B-cell multiplication. On the supernatants of B-cell-T-cell cocultures, we examined by the ELISA technique the effect of T cells on Ig synthesis. Contrary to CD57- T cells, whose effect was strong, CD57+ T cells weakly stimulated Ig synthesis. More IgM than IgG was generally found. Because CD57 Antigen is a typical marker of natural killer cells, we tested the cytolytic activity of tonsillar CD4+ CD57+ cells on K562 target cells. Unlike NK cells, neither CD4+CD57+ nor CD4+ CD57- cells exhibit any cytotoxicity. Thus, germinal center CD4+ CD57+ cells are not cytolytic and do not strongly stimulate either B-cell proliferation or Ig secretion. CD4+ CD57- cells, however, enhance B-cell proliferation and differentiation, thus acting like the classical helper cells of the T-dependent areas.

  • Ultrastructure of CD57+ cells isolated from human tonsils or blood.
    European Journal of Morphology, 1993
    Co-Authors: F. Bouzahzah, A. Bosseloir, Ernst Heinen, Nadine Antoine, I. Mancini, Léon J. Simar
    Abstract:

    : The presence of CD4+, CD57+ T cells in the germinal centers has been reported by several authors. The CD57 Antigen is also expressed by natural killer (NK) cells. We purified CD57+ cells from human tonsils and blood by microdissection, rosetting with sheep red blood cells and magnetic cell sorting (MACS) and examined the ultrastructural morphology of these cells. Clear differences were found in cell aspect: blood NK contained large granules which were not found in the tonsillar CD57+ cells. These latter appeared medium-sized and not fully activated. After immunolabeling, the tonsillar CD57+ cells were mainly found in the light zone of the germinal centers.