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J.a. Hansen - One of the best experts on this subject based on the ideXlab platform.

  • Mixed Leukocyte Culture reactivity and graft-versus-host disease in HLA-identical marrow transplantation for leukemia.
    Bone marrow transplantation, 1992
    Co-Authors: G C Degast, Eric Mickelson, Patrick G. Beatty, Amos D, Keith M. Sullivan, H G Schoch, J.a. Hansen
    Abstract:

    The results of pretransplant mixed Leukocyte Culture (MLC) assays were compared to subsequent risk of graft-versus-host disease (GVHD) in 783 patients receiving marrow transplants from HLA genotypically identical sibling donors. The mean MLC response observed between 1303 normal HLA identical sibling pairs was 0.0 +/- 4.2% RR. The donor anti-recipient MLC reaction, an in vitro response that presumably might be relevant to GVHD, was significantly increased (greater than mean + 2 sd) in 83 (10.6%) of the cases, most often in patients in relapse at the time of testing. No association was found, however, between this increased donor anti-recipient MLC reactivity pretransplant and the incidence or severity of subsequent acute or chronic GVHD. These data suggest that the increased MLC responses sometimes observed between leukemia patients and their HLA identical sibling donors prior to marrow transplantation do not represent genetic differences capable of causing GVHD.

J.j. Rood - One of the best experts on this subject based on the ideXlab platform.

  • MHC Restricted Dual Specific Inhibition of Mixed Leukocyte Culture Reactions by Human HLA Antibody Molecules
    Tissue antigens, 2008
    Co-Authors: E. Rooij‐doyer, M. Jonker, J. W. Bruning, J.j. Rood
    Abstract:

    A human alloantiserum was found which selectively inhibits responding cells in mixed Leukocyte Culture reactions. Inhibition was achieved by pre-incubation of responder cells in the antiserum followed by washing. The serum showed dual specificity as an inhibiting agent. First, inhibition was restricted to HLA-B7 or -B40 positive stimulator cells, specificities against which the antiserum also had cytotoxic activity. Second, inhibition was almost exclusively associated with the presence of the phenotype HLA-Al, -B8 on the responder cells The HLA associated specificity for responder cells was unexpected since no alloantibody activity directed to responder alloantigens could be detected by conventional serological methods. The antiserum donor had not been immunized with HLA-Al, -B8 antigens nor with known crossreactive antigens. Furthermore, the serum donor did not carry HLA-Al, -B8 antigens herself. The inhibiting substance in the antiserum had physicochemical properties of IgG and was specifically reactive with HLA-B7 positive platelets. Pepsin digest preparations were not inhibitory. Fc receptor positive responder cells were required for inhibition. Responder cells, preincu-bated with the antiserum, suppressed the response of cells not incubated with the antiserum. Three possible explanations of these results are discussed: specific binding of the Fc part of the antibody with Fc receptors of responder cells, specific activation of suppressor cells and cross-reactivity.

I Nakashima - One of the best experts on this subject based on the ideXlab platform.

  • promotion of cytotoxic t cell generation in mixed Leukocyte Culture by phosphatidylinositol specific phospholipase c from bacillus thuringiensis
    Infection and Immunity, 1995
    Co-Authors: S M Rahman, Meiyi Pu, Hong Yi, Kozo Ohkusu, Masashi Kato, Kenichi Isobe, Ryo Taguchi, Hiroh Ikezawa, I Nakashima
    Abstract:

    Phosphatidylinositol-specific phospholipase C (PIPLC) from Bacillus thuringiensis, which cleaves phosphatidylinositol or glycosylphosphatidylinositol on the external cell surface to generate a second messenger for intracellular signal transduction (S. Rahman et al., FEBS Lett. 303 :193-196, 1992), was found to preferentially promote the generation of alloantigen-specific cytotoxic T lymphocytes in mixed Leukocyte Culture. PIPLC affected an early stage of cytotoxic T-lymphocyte activation in Culture, and there was no evidence of any soluble cellular mediators of this PIPLC action. PIPLC neither enhanced overall cell proliferation nor noticeably promoted interleukin-2 and -4 production in mixed Leukocyte Culture. The relative population size of Ly-2 + T cells was increased, however, in a late mixed Leukocyte Culture with PIPLC. In addition, PIPLC enhanced an anti-CD3 monoclonal antibody-induced early increase in [Ca 2+ ] i . These results suggest a new parasite (bacterium)-oriented mechanism for enhancing antigen-driven host cytotoxic T-lymphocyte immunity which does not include promotion of interleukin-2 production.

G C Degast - One of the best experts on this subject based on the ideXlab platform.

  • Mixed Leukocyte Culture reactivity and graft-versus-host disease in HLA-identical marrow transplantation for leukemia.
    Bone marrow transplantation, 1992
    Co-Authors: G C Degast, Eric Mickelson, Patrick G. Beatty, Amos D, Keith M. Sullivan, H G Schoch, J.a. Hansen
    Abstract:

    The results of pretransplant mixed Leukocyte Culture (MLC) assays were compared to subsequent risk of graft-versus-host disease (GVHD) in 783 patients receiving marrow transplants from HLA genotypically identical sibling donors. The mean MLC response observed between 1303 normal HLA identical sibling pairs was 0.0 +/- 4.2% RR. The donor anti-recipient MLC reaction, an in vitro response that presumably might be relevant to GVHD, was significantly increased (greater than mean + 2 sd) in 83 (10.6%) of the cases, most often in patients in relapse at the time of testing. No association was found, however, between this increased donor anti-recipient MLC reactivity pretransplant and the incidence or severity of subsequent acute or chronic GVHD. These data suggest that the increased MLC responses sometimes observed between leukemia patients and their HLA identical sibling donors prior to marrow transplantation do not represent genetic differences capable of causing GVHD.

H. Bach - One of the best experts on this subject based on the ideXlab platform.

  • IN VITRO SENSITIZATION OF THYMOCYTES Role of H-2 I Region Determinants and Cell-Free Mixed Leukocyte Culture Supernates in Generation of Cytotoxic Responses*
    2013
    Co-Authors: Mohan Sopori, Alon Bernstein, H. Bach
    Abstract:

    In in vitro mixed Leukocyte Culture (MLC) J reactions, cytotoxic T lymphocytes (CTLs) are generated when responding and stimulating (usually y-irradiated or mitornycin-C treated) cells differ for certain antigens determined by the major histocompatibility complex (1). Genetic experiments have revealed that in mice, the strongest of the antigens recognized by CTLs on the target cells are coded by K and D regions of the H-2 complex (2). Although there is sufficient evidence to indicate that differences between responding and stimulating cells of either the K or D region alone will lead to generation of CTLs, in most situations additional disparity for the H-2 I region is needed to obtain an optimal response. Such findings have led to the two signal hypothesis for in vivo and in vitro activation of CTLs (2, 3). In recent years, several groups have demonstrated that soluble factors found in MLC supernates can, in the presence of a K- or D-region difference, substitute for the I region different stimulating cells by enhancing a weak cytotoxic response to a strong one (3-7). These studies have used spleen or lymph node cells as responders for the generation ofCTLs. Unfractionated thymocytes, on the other hand, are poor responder

  • GENETIC AND CELLULAR ASPECTS OF XENOGENEIC MIXED Leukocyte Culture REACTION*
    2013
    Co-Authors: Fischer Lindahl, H. Bach
    Abstract:

    Xenogeneic lymphocytes can induce proliferative responses in the mixed lymphocyte Culture (MLC) ~ which are as strong as those induced by allogeneic lymphocytes (1). It is impossible to determine directly which lymphocyte antigens stimulate the xenogeneic MLC response. The recently described "primed lymphocyte typing " (PLT) assay (2) has made it possible to determine indirectly the genetic control of xenogeneic MLC. Sensitization in a mixed lymphocyte Culture positively selects for memory cells which give a rapid secondary response upon restimulation with cells from the initial stimulator (3, 4). Studies in human families (2, 5-7) showed that restimulation is caused by the same LD determinants of the major histocompatibility complex (MHC) that induce primary MLC responses. In this paper we present studies of human lymphocytes which were sensitized to cells of a single mouse strain and restimulated with cells from a variety of strains. By choosing combinations of primary and secondary stimulator which shared only certain parts of their genetic material, we could assay the relative importance of non-H-2 and various H-2 antigens for activation of human lymphocytes. The results suggest that the same antigens are important in allogeneic and xenogeneic MLC reactions. The ability of human Leukocyte subpopulations to respond in xenogeneic MLC further suggest that the cellular requirements of allogeneic and xenogeneic MLC responses are the same. Materials and Methods Mice. Mice used in this study were bred in our own colony or purchased from The Jackso

  • Brief Definitive Report THREE HLA-D REGION ANTIGENS DEFINED BY PRIMED LD TYPING*
    2013
    Co-Authors: H. Bach, Esther Jarrett-toth, Claudia J. Benike, Michael J, Paul M. Sondel, L. Bach
    Abstract:

    Definition of cell-surface antigens determined by the genes of the major histocompatibility complex in man, HLA, has been performed for purposes of matching donor and recipient for transplantation, for studying associations between HLA antigens and disease, and for genetic studies (1). Four HLA loci, HLA-A, HLA-B, HLA-C, and HLA-D have been identified. Until recently, HLA-D disparity could only be assayed in mixed Leukocyte Culture (MLC) tests (2, 3). In 1972, Bradley et al. (4) introduced the homozygous typing cell (HTC) test in which HLA-D antigens were defined by stimulating cells in MLC that were homozygous for the locus (loci) determining the MLC stimulatory, or LD, antigens. If the responding cell in MLC carried the same HLA-D antigen(s) as the HTC, no response occurred. The HTC test has been used in man to define eight "clusters " of HLA-D antigens called HLA-DWl through HLA-DW6, LD 107, and LD 108 (5). We have developed a new test, called primed LD typing or PLT, to define HLA-D antigens (6-9). The reagents CPLT cells") are prepared in vitro, in a