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F H Bach

Publications and source records attributed to F H Bach.

At least 343 records · Page 19Linked to original sources
PubMed1981

Early detection and specificity analysis of human cytolytic T lymphocyte (CTL) colonies generated in soft agarose culture: a potential assay for definition of CTL defined (CD) determinants.

In this communication we describe and early, large-scale screening assay for the detection of colonies with varied cytolytic specificity. The colonies are generated in soft agarose culture from day 3 mixed lymphocyte culture (MLC) alloactivated cells. A cell mediated lympholysis (CML) assay utilizing as few as 500 target cells has made it possible to prescreen for cytolytic T lymphocyte (CTL) colonies and to test for antigen specificities as early as 11 and 14 days, respectively, after MLC priming. Large numbers of colonies, from 80 to over 150, have been prescreened against a specific sensitizing target cell, and as many as 30 CTL colonies have been simultaneously tested against a panel of multiple targets carrying defined HLA-A, -B, -C, -DR antigens to evaluate antigen specificity. All CTL colonies are lytic against the specific sensitizing target cell and do not lyse the target autologous to the responder. Some are found to be operationally specific in that they lyse only those target cells which share HLA serologically defined (SD) antigens with the sensitizing cells, and other show cytolytic patterns which are not correlated with known HLA-SD antigens. These observations support, at a much finer level of analysis, the possible distinction between SD and CTL defined (CD) determinants.

Cells, Cultured↗
PubMed1981

Sensitization of lymphocytes against pooled allogeneic cells. II. Characterization of effector cells cytotoxic for autologous lymphoblastoid cell lines.

Stimulation of human lymphocytes in mixed leukocyte culture (MLC) with x-irradiated pooled allogeneic normal cells (poolx) was previously shown to result in generation of effector cells cytotoxic for autologous Epstein-Barr virus- (EBV) transformed lymphoblastoid cell lines (LCL). This study was undertaken to determine whether lysis of the autologous EBV- transformed LCL cells by pool-stimulated cells is mediated by cytotoxic Tc lymphocytes (Tc) or natural killer- (NK) like cells, both of which are generated in MLC. In the first series of experiments, proliferating cells were eliminated by treatment of pool-stimulated cells with 5 X 10(-5) M 5-bromodeoxyuridine (BUdR) and light. The remaining cells failed to lyse allogeneic normal lymphocytes and autologous LCL cells, whereas cytotoxicity against NK-sensitive K562 leukemia cells was retained. In the second series of experiments, pool-stimulated effector cells were treated with monoclonal anti-human Tc cell antibodies, OKT3 or OKT8, and complement (C). The cells recovered after antibody and C treatment were diminished in their ability to lyse allogeneic normal lymphocytes as well as autologous LCL cells, whereas their cytotoxicity against K562 leukemia cells was unaffected. These combined results provide strong evidence that lysis of autologous LCL cells by lymphocytes stimulated with pooled allogeneic normal cells is mediated by Tc rather than NK-like cells.

Bromodeoxyuridine↗
PubMed1981

Helper cells in murine thymus for the generation of primary cytolytic T lymphocyte (CTL) responses in vitro.

Thymocytes used as responding cells in a mixed leukocyte culture with gamma-irradiated splenic stimulating cells generated highly significant proliferative and cytolytic responses when responding and stimulating cells differed by the entire H-2 complex or at H-2K plus H-21 regions. On the other hand, when the difference was only an H-2K region, very little, if any, proliferative response was detectable and no cytolytic response was found. Because it has been claimed by others that thymocytes do not include cells needed to provide the help required for the generation of a cytolytic response and yet we have found a highly significant response in thymocytes, we have analyzed, in 2 systems, the possible role of back-response by stimulating spleen cells in the generation of cytolytic activity by responding thymocytes. In the first system, spleen cells were depleted of T lymphocytes by treatment with anti-Thy-1.2 antiserum plus complement. In the second system, F1 hybrid mouse spleen cells were used to stimulate parental responding thymocytes. In both cases, no back-response as measured by cell proliferation in mixed leukocyte culture was detected, while both types of spleen cells still stimulate significant cell proliferation and cytolytic activity from responding thymocytes, as well as from responding spleen cells. Furthermore, it was found that in the presence of stimulating spleen cells (either T lymphocyte-depleted or not) that differ from the responding thymocytes at the entire H-2 complex, thymocytes were capable of generating a significant and specific cytolytic response to H-2K region different stimulating spleen cells (either T lymphocyte-depleted or not). These results are compatible with the suggestion that there are sufficient numbers of helper cells in the unfractionated thymocyte population for the generation of primary cytolytic T lymphocyte responses in vitro.

Animals↗
PubMed1981

Allo-responsive T lymphocytes and their differentiation markers.

Functionally disparate subpopulations of T lymphocytes that respond to alloantigens, primarily as studied in vitro in the mixed leukocyte culture and cell mediated lympholysis assays, have been separated most usefully by cell surface markers that can be identified with antiserums. Based on the data available to date there are at least two, and perhaps three, T lymphocyte subpopulations responsive to alloantigens in vitro, which include helper, cytotoxic, and perhaps suppressor T lymphocytes. Reviewed in this paper are data pertaining to the question of whether two types of cytotoxic T lymphocytes exist and whether true memory cytotoxic T lymphocytes are generated following in vitro or in vivo priming. Further, two systems are discussed that served as differentiation markers on lymphocytes: the Ly antigens and a family of large cell surface membrane proteins (LMPs).

Animals↗
PubMed1980

Cloned primed-lymphocyte-test reagents in the dissection of HLA-D.

Human T lymphocytes obtained as blasts on day 4 from a primary mixed leukocyte culture (MLC) were cloned in the presence of T cell growth factor (TCGF) and feeder cells. Parameters important in producing higher-specific-activity TCGF were evaluated; irradiation of the responding cells as well as removal of adherent cells or inclusion of indomethacin in the culture was important. In addition, the presence of an irradiated lymphoblastoid cell line (LCL) cell in the TCGF-producing system enhanced activity in the supernate. The long-term maintenance of progeny from clones was achieved by utilizing the LCL autologous with either the responding or sensitizing cells from the initial MLC as feeder cells. Under those conditions, clones could be expanded for 7 or more wk with the maintenance of PLT reactivity. Had all the cells in each clone been maintained for the full 7 wk, more than 1 X 10(10) cells could have been developed in each clone. The cloned reagents provide a higher degree of antigen-specific reactivity than do normal PLT cells. It is to be anticipated that as the requirements for cloning are made more stringent, including the recloning of the cells, these reagents will aid greatly in the dissection of the complexity attendant to HLA-D.

Clone Cells↗
PubMed1980

Complexity of the HLA-D region studied by primed-lymphocyte test.

The results obtained by mixed lymphocyte culture (MLC), HLA-D and -DR typing, and primed lymphocyte test (PLT) in the F. family give some indication of the complexity of the HLA-D region in man. Two siblings identical for HLA-A, -B, -C, -D, and -DR by typing are mutually MLC-stimulatory. PLT studies indicate that one of these siblings expresses D-region determinants of both of the mother's haplo-types, suggesting an intra-D recombinant. These results suggest that the D region contains genes for a number of different determinants.

Epitopes↗
PubMed1980

Generation of primary cytotoxic lymphocytes against non-major histocompatibility complex antigens by anti-Ia serum plus complement-treated lymphocytes.

The results presented in this paper demonstrate that responding cells that remain after anti-Ia serum plus complement (C) treatment generate a highly significant in vitro cytotoxic response against minor histocompatibility complex antigens. The cytotoxic response appears to be antigen specific in that target cells of strains other than the sensitizing strain are not lysed, or lysed to a lesser extent. The cytotoxic cells are susceptible to anti-Thy-1 plus C lysis. Anti-Ia serum may function by removing an unprimed suppressor cell, although other mechanisms cannot be ruled out.

Animals↗