Biomedical subjects

F H Bach

Publications and source records attributed to F H Bach.

At least 307 records · Page 17Linked to original sources

PubMed1984

OKT4+ cytotoxic T cells can lyse targets via class I molecules and can be blocked by monoclonal antibody against T4 molecules.

Human cytotoxic T lymphocytes (CTL) have been shown to recognize either class I or class II major histocompatibility (MHC) products. This recognition has been correlated with the expression of OKT antigens on the surface of the CTL. Thus, OKT4+ CTL have been shown to be reactive with class II products, whereas OKT8+ effectors recognize class I molecules. In this study, responder cells were separated according to their OKT4 or OKT8 cell surface phenotype on a fluorescence-activated cell sorter (FACS). The OKT4+ subsets were stimulated with an LCL mutant that did not express DR and MB/MT but did express SB and class I antigens. After 7 days in culture, the activated subsets were tested on a panel of class I matched or mismatched targets. The cytotoxicity observed could be correlated with the presence of matched class I antigens. In addition, monoclonal antibody (MCA) W6/32, directed at a monomorphic determinant on HLA-A and -B molecules, blocked lysis. Furthermore, six OKT4+ CTL clones were derived from the OKT4+ bulk cultures; three clones were found to be directed at class I molecules whereas the other three recognized class II determinants. The ability of these clones to lyse their relevant targets was blocked by OKT4 MCA, raising questions as to the role of the T4 molecule in antigen class-specific CTL recognition.

Animals↗

PubMed1984

High frequency of splenic anti-class I cytotoxic T lymphocyte precursors correlates with in vivo rejection of K/D region disparate thyroid and islet grafts in mice.

The relationship between the ability of different recombinant mouse strains to reject thyroid and pancreatic islet grafts that differ in class I antigens and the frequencies of the recipients' cytolytic T lymphocyte precursors (CTL-P) directed against donor antigens was examined. We analyzed three different pairs of D region histoincompatible recombinant mouse strains in which unidirectional thyroid graft rejection occurred. Frequency analysis of their splenic CTL-P demonstrated that the mouse strains that rejected the grafts exhibit a relatively high CTL-P frequency against the donor D region-encoded alloantigens at a magnitude similar to that directed against a third party, which differ in the entire H-2 complex. Mouse strains that did not reject thyroid grafts exhibited a relatively low CTL-P frequency against the donor alloantigens, but a normal high frequency against alloantigens encoded by the entire H-2 complex of a third party strain. The effect of different routes of immunization on the two parameters was tested in B10.S(7R) mice, which accept B10.S thyroid grafts permanently. Immunization of B10.S(7R) mice by injection of 50 X 10(6) B10.S spleen cells i.p. did not confer the ability to reject B10.S thyroid grafts and did not affect the low splenic anti-B10.S CTL-P frequency. By contrast, B10.S(7R) mice that were immunized by transplantation of B10.S skin rejected a subsequent B10.S thyroid graft and at the same time demonstrated a fourfold increase in the specific CTL-P frequency. We found that the ability to reject thyroid and pancreatic islet grafts always correlated with high CTL-P frequency against the donor alloantigens; however, acceptance of allografts was not always correlated with low CTL-P frequency. We assume, therefore, that the high frequency of CTL-P against donor alloantigens may be a prerequisite (but is not always sufficient) for rejection of K/D region disparate thyroid and pancreatic islet grafts.

Animals↗

PubMed1983

Dw/LD-related molecular polymorphism of DR4 beta-chains.

The results of this study demonstrate the existence of molecular heterogeneity (polymorphism) within DR beta-chains isolated from a single serologically defined DR phenotype, DR4. The data are consistent with the possibility that this polymorphism is related to the Dw/LD phenotype as defined with the cellular reagents, homozygous typing cells.

B-Lymphocytes↗

PubMed1983

H-2 antigen class: effect on mouse islet allograft rejection.

Rejection of mouse pancreatic islet allografts occurred in a high percentage of donor recipient combinations identical for H-21-region antigens and differing at H-2K and H-2K + H-2D without I-region disparities. The results suggest that disparities in major histocompatibility complex antigens of class I (H-2K and H-2D) alone are capable of eliciting islet allograft rejection, and that lack of a stimulus from class II (I-region) alloantigens does not ensure permanent islet allograft survival.

Animals↗

PubMed1983

Human anti-lymphoma responses generated in vitro and in vivo following sensitization with allogeneic leukocytes.

Peripheral blood lymphocytes (PBL) from a patient with poorly differentiated lymphocyte lymphoma (PDLL), after stimulation for 7 days with X-irradiated allogeneic lymphocytes pooled from three or ten donors (poolx), were cytotoxic for autologous lymphoma cells. Some clones lytic for autologous lymphoma cells, that were derived from this patient's pool-stimulated cells, resembled cytotoxic T lymphocytes (CTL), while other clones resembled natural killer (NK)-like cells in that they also lysed NK-sensitive HLA-negative K562 cells. In a second patient with more advanced PDLL, PDL cultured with T-cell growth factor (which is produced following stimulation with mitogens or alloantigens) lysed autologous lymphoma cells. On the basis of these in vitro findings, we asked whether IV transfusions with X-irradiated allogeneic leukocytes would result in anti-lymphoma responses in vivo. Ten days after transfusions with X-irradiated leukocytes from four unrelated donors, the first patient's two previously palpable nodes were no longer palpable and he remained in complete clinical remission for 6 months. The second patient had a temporary partial remission with dramatic reduction in size of multiple cervical and axillary nodes within 2 weeks after receiving the leukocyte transfusions.

Cells, Cultured↗

PubMed1983

Differences in susceptibility to rejection of mouse pancreatic islet allografts disparate for class I or class II major histocompatibility antigens.

Pancreatic islet B cells express class I but not class II antigens, and removal of Ia positive passenger cells from H-2 allogeneic islets by anti-Ia serum and complement leads to permanent allograft survival. A test was made of whether the same result can be achieved by genetically removing the Ia stimulus by performing mouse islet allografts in congenic donor-recipient combinations differing at the H-2 K only, D only, or K + D regions. Mice disparate for class I antigens (H-2 K, D, and K + D) alone reject islet allografts, suggesting that Ia positive passenger cells may be involved in presentation of class I disparities. Established islet allografts appear to be sensitive to rejection induced by injection of donor strain splenocytes when donor and recipient differ for class I (H-2 D alone and D + I) but not class II (H-2 I alone) antigens. These results are consistent with the hypothesis that pancreatic islet allografts do not express class II target antigens, but do express class I antigens that in long-established pancreatic islet allografts are capable of acting as targets but not in initiating an immune response.

Animals↗

PubMed1983

Clonal analysis of T lymphocyte response to an isolated class I disparity.

A bulk primed lymphocyte reagent generated in a class II identical class I (HLA-B) disparate sibling combination demonstrated both cytotoxic [cell mediated lympholysis (CML)] and proliferative [i.e., primed LD (lymphocyte) typing (PLT)] reactivity associated with the class I antigen, Bw62. Cells from this bulk population were plated by limiting dilution and cloned by micromanipulation. Three functional groups of clones were isolated. Some clones derived were found specifically to proliferate to and lyse cells bearing the Bw62 antigen. Based on such reactivities, these clones were analogous to the class of antigen-driven, helper cell independent cytotoxic (HITc) clones previously reported from our laboratories. Other clones responded proliferatively to stimulation by Bw62 positive cells but were not cytotoxic, thus fitting characteristics of Th, although it will be necessary to test such clones for their ability to produce Interleukin 2 (IL-2). In addition, conventional cytotoxic clones which did not proliferative to, but did lyse cells bearing the Bw62 antigen were isolated. The results were consistent with the existence of both HITc and Tc mediated cytotoxicity generated against this isolated class I disparity.

Clone Cells↗

PubMed1983

Genetic and molecular analyses of lymphocyte-defined HLA-D region specificities.

Determinants encoded in the HLA-D region have been studied with both cellular (PLT) and molecular (SDS-IEF) methods. When the PLT response against a lymphoblastoid cell line was analyzed by limiting dilution culture and determination of the reactivity of individual cultures against a panel of loss mutants of the initial stimulating LCL, a large fraction of the cultures showed the same pattern, apparently recognizing a determinant associated with DR. In two-dimensional gel analysis of several DR4-positive HLA-D region homozygous cells, the IEF pattern of the DR beta chain correlated with the Dw specificity expressed by the cell. These two pieces of evidence suggest that, although many determinants may contribute to reactivity in mixed leucocyte culture or PLT, an immunodominant determinant associated with the DR beta chain may be the most important single factor in the assignment of Dw specificity.

Epitopes↗

PubMed1983

Antigen specificity and helper characteristics of antigen-driven helper-cell-independent cytolytic T lymphocytes.

Antigen-driven, helper-cell-independent cytolytic T lymphocytes, which proliferate in response to antigenic stimulation independently of exogenous lymphokines, were characterized with regard to antigen specificity and helper factor production. Mapping data indicate that the determinants recognized by such cells for cytotoxicity and proliferation induction are identical. In addition, the cells were shown to function like helper cells in that they secrete soluble IL-2-like factor upon stimulation with the sensitizing antigens. The potential importance of this cell type in the immune response is discussed.

Animals↗

PubMed1983

Thyroid graft rejection between C57BL/6 and H-2Kb mutant mice. Differences in the immunogenic expression of the mutated molecule on thyroids of six different mutants.

Mice that possess mutations in the H-2 region were selected by means of skin grafting. We tested the survival time of thyroid grafts transplanted between C57BL/6 mice and their descendent H-2Kb mutant mice and compared the kinetics of skin versus thyroid graft rejection in each of the mouse strain combinations tested. The results demonstrated that reciprocal thyroid grafts between C57BL/6 mice and bm1, bm3, bm4, bm5, and bm6 mutants are accepted for long periods. The bm8 mutant appeared to be an exception because a small fraction of reciprocal thyroid grafts were rejected between bm8 and C57BL/6 mice. Transplantation of C57BL/6 mice with skin grafts from bm1, bm3, bm4, and bm8 donors induced rejection of subsequent thyroid grafts syngeneic with the skin. Thyroid grafts of bm5 and bm6 were not rejected by C57BL/6 mice even after preimmunization with bm5 and bm6 skin grafts. In contrast to skin grafts, innoculation of C57BL/6 mice with 50 X 10(6) spleen cells from mutant mice failed to immunize the recipients and induce rejection of mutant thyroid grafts. The results indicate that skin graft rejection assays and in vitro cell-mediated lympholysis (CML) typing can not always predict the consequence of transplantation of organs such as thyroid, and also that alterations in the H-2Kb molecule as a result of spontaneous mutations can give rise to mutated molecules that differ in their immunogenic and antigenic properties when expressed on thyroid cells, as compared with skin.

Animals↗

PubMed1983

The effect of mismatching for HLA-DR in recipients of renal allografts sharing one HLA-ABC haplotype with related donors.

The effects of mismatching for DR antigens on renal allograft survival rates have largely been restricted to analyses of cadaver transplant results. Analyses of HLA matching in recipients of transplants from related donors have focused on the number of haplotypes shared between the recipients without regard to DR, or on the total number of HLA antigens mismatched, or on the degree of MLC responsiveness of the recipient to the donor. Most related donor-recipient pairs sharing only one HLA haplotype will be mismatched for DR at the other haplotype, but because there are a limited number of DR alleles, sharing of DR antigens on the mismatched haplotypes occurs relatively frequently. To determine the influence of mismatching for DR on the fate of renal allografts from related donors, we analyzed the results of 172 kidney transplants from related donors who shared one HLA-ABC haplotype with the recipient. There were 156 primary grafts and 16 retransplants; 147 donor-recipient pairs were satisfactory typed for DR antigens. Because genotyping was not usually done, we performed two analyses under two different assumptions. The first assumption was that individuals expressing less than or equal to 1 DR antigen had null antigens, or were homozygous for DR; the alternative assumption was that blanks were true antigens and individuals with blanks were heterozygous. The first assumption is more likely to be correct, and is the assumption used in most analyses of the effect of DR antigen mismatches on the results of cadaveric transplantation. Under the first assumption, of the 147 related donor-recipient pairs in whom DR typing was satisfactory, 33% were mismatched for 0, 64% for 1, and 3% for 2 DR antigens. The one-year absolute graft survival rates in recipients of kidneys from donors with 0 mismatches for DR was 92% (n = 49); in those with one mismatch for DR it was 82% (n = 94); and from those with two mismatches it was 50% (n = 4). The one-year graft survival rate in 25 donor-recipient pairs in which one or both members could not be satisfactorily DR typed was 76%. Differences in graft survival rates between the 0 and 1 and the 1 and 2 DR-mismatched groups were not statistically significant.(ABSTRACT TRUNCATED AT 400 WORDS)

Graft Rejection↗

PubMed1983

Lack of donor-specific tolerance in mice with established anti-Ia-treated islet allografts.

Pancreatic islet allografts pretreated in vitro with monoclonal Ia antibody and transplanted beneath the renal capsule result in normoglycemia beyond 100 days in streptozotocin-induced diabetic recipient mice that differ only at H-2 K, H-2 K + I, or H-2 K + I + D from the donors. Mice with established islet allografts are not tolerant of donor-specific skin or islet antigens, but rather reject donor skin grafts in an accelerated fashion. Established anti-Ia antibody pretreated islet allografts continue to express target antigens and remain susceptible to rejection after challenge with donor skin grafts.

Animals↗

PubMed1983

Analysis of cloned T cell function. II. Differential blockade of various cloned T cell functions by cyclosporine.

Cyclosporine has profound suppressive effects on selected in vitro functions of cloned T lymphocytes. Cyclosporine inhibits the antigen-induced proliferation of the helper T cell clone 12-11. The effective dose required to reduce this response by 50% (ED50) is 28 ng/ml. In contrast, the proliferation of clone 12-11 induced by exogenous growth factors in secondary mixed lymphocyte culture supernatant (2 degrees MLC SN), is relatively insensitive to cyclosporine (ED50 = 4600 ng/ml). Furthermore, cyclosporine abrogates both antigen-induced and mitogen-induced secretion of lymphokines by clone 12-11, indicating that cloned helper T cell function is sensitive to cyclosporine even when interactions between specific alloantigens and their cell surface receptors are bypassed with mitogen. The suppressive effect of cyclosporine is not limited to helper T cell clones. The cytolytic T lymphocyte (CTL) clone 5MD2-2 is also sensitive to cyclosporine. Again, cyclosporine (100 ng/ml) blocks the antigen-driven, but not the exogenous lymphokine-driven, component of clone 5MD2-2 proliferation. This suppression does not result from the occlusion of antigen receptors or from antigen deformation by cyclosporine, because clone 5MD2-2 remains capable of antigen-specific cytolysis in the presence of cyclosporine concentrations that can suppress its proliferation. Finally, the ability of clone 5MD2-2 to remove IL-2 activity from culture media, a function that is significantly enhanced by contact with specific alloantigen, is not influenced by suppressive cyclosporine concentrations.

Animals↗

PubMed1983

Primed lymphocyte typing predicts MLC reactivity between unrelated individuals.

The present study was carried out to evaluate the ability of primed lymphocyte typing (PLT) to predict mixed lymphocyte culture (MLC) reactivity between unrelated individuals. Eleven PLT cells generated against independent familial haplotypes, and one PLT cell generated against a homozygous typing cell (HTC), were tested for their response to cells of a random panel of 53 unrelated individuals. From Chi-square analysis of the response patterns of these 12 cells, nine "PLT specificities" could be defined. Most panel members (81.2%) types for 1 or 2 of these specificities; equal numbers (9.4%) types for 3 or none, respectively. Four of these 9 specificities were shown to be significantly correlated with HLA-Dw antigens defined by HTCs. Typing for these nine PLT specificities was found to be predictive of subsequent primary MLC reactivity between panel members: a) pairs of panel members sharing PLT specificities produced three-fold lower MLC results on the average than pairs of panel members disparate for PLT specificities (p less than 0.0001), and b) in MLC combinations, an increase in number of foreign PLT specificities presented by the stimulator cell was paralleled by a statistically significant increase in MLC reactivity. To the extent that low MLC reactivity is correlated with improved graft survival, the PLT method could have significant value in selecting histocompatible donors for organ transplantation.

HLA-DR Antigens↗

PubMed1983

Helper cell-independent cytolytic T lymphocytes specific for a minor histocompatibility antigen.

We have isolated several anti-H-2Db-restricted cytolytic T cell clones specific for the minor histocompatibility antigen, H-1, from a long-term B10.129(5M) anti-C57BL/6 mixed leukocyte culture. All proliferate significantly, in the absence of exogenously added lymphokine, and in a specific manner to H-2Db-compatible stimulator cells that carry the appropriate H-1 minor antigen. Moreover, significant proliferation also occurs when T cell-depleted stimulator cells are used as the antigenic stimulus, indicating that the proliferative capacity of these clones is not the result of T cell factors produced by the stimulator cells. After concanavalin A stimulation, IL 2-like lymphokine activity can be detected from the one clone tested, 5M/B6-5. These data demonstrate the existence of antigen-driven, helper T cell-independent cytolytic T cell clones responsive to a single minor histocompatibility antigen. The implications of this finding are discussed.

Animals↗

PubMed1983

Depletion of human NK cells with monoclonal antibodies allows the generation of cytotoxic T lymphocytes without NK-like cells in mixed cultures.

In vitro stimulation of human mononuclear cells with x-irradiated autologous lymphoblastoid cell line (LCL) or allogeneic normal cells in mixed leukocyte cultures (MLC) was previously shown to result in the generation of OKT3+ OKT8+ cytotoxic T lymphocytes (CTL) lytic for allogeneic and autologous LCLs and also of natural killer- (NK) like cells that are OKT3- and primarily OKT8- and are lytic for HLA- NK-sensitive K562 cells. The origin of the NK-like cells was not previously known because, although the majority of fresh human NK cells react with monoclonal antibodies OKM1 and B73.1, lymphocytes bearing these markers are not detected several days after the onset of MLC, when NK-like cells are present. In this study, experiments were undertaken to determine whether NK-like cells generated after stimulation with x-irradiated pooled allogeneic normal cells (poolx) or with autologous LCL are derived from cells expressing antigens reactive with monoclonal antibodies OKM1 or B73.1, which react with fresh NK cells. Mononuclear cells, depleted of monocytes, were stained with OKM1 or B73.1 and fluorescein-labeled goat anti-mouse IgG. Lymphocytes depleted of OKM1+ or B73.1+ cells, by fluorescence-activated cell sorting, and lymphocytes that were stained but not sorted were stimulated for 7 days with either poolx or autologous LCL. The generation of NK-like activity was decreased at least 90% after depletion of cells reactive with OKM1 or B73.1, whereas the generation of CTL against autologous and allogeneic LCL was minimally affected. These findings show that NK-like cells generated in MLC are derived from cells that express the phenotype of fresh NK cells (OKM1+ or B73.1+) and that CTL can be generated in cultures in which relatively little NK-like activity is concomitantly detected, by depleting NK cells with monoclonal antibodies before stimulation.

Animals↗

PubMed1983

Phorbol myristate acetate and in vitro T lymphocyte function. II. Influence of PMA and supernatants from PMA-treated P388D1 cells on the proliferation of cloned T cells.

Neither the culture supernatants from P388D1 cells pulsed with phorbol myristate acetate (PMA), nor PMA itself in concentrations ranging from 10(-6) M to 10(-9) M, are directly mitogenic for murine T lymphocyte clones, yet both markedly augment the antigen-driven proliferation of many, but not all, cloned T lymphocytes. The component of PMA-induced P388D1 supernatant responsible for its co-mitogenic activity is probably PMA, rather than interleukin 1. For responsive clones, the co-mitogenic effect of PMA requires stimulator cells that display the specific allogeneic determinants recognized by the clones. This response persists after T cells are removed from the stimulating population, ruling out induction of mitogenic lymphokines from stimulator T cells by PMA as a primary mechanism for augmentation of clonal proliferation. Both splenocytes and thymocytes cooperate with PMA for enhanced clonal expansion, but heat treatment (45 degrees C, 45 min) of thymocytes destroys their cooperative capacity. PMA can also potentiate the lymphokine-driven proliferation of cloned T cells, indicating that PMA can, under certain conditions, influence T cell clonal expansion by a direct action on T lymphocytes.

Animals↗

PubMed1983

A comparison of the neonatal tolerance-inducing capacities of H-2 class I and class II antigens.

We have investigated the abilities of murine major histocompatibility complex-encoded antigens to induce in vitro hyporeactivity of T lymphocytes when these antigens are injected neonatally. Class I molecules, presented on F1 donor cells having an H-2 K or D region difference from recipients, can readily induce tolerogen-specific cytotoxic T cell hyporeactivity; as few as 1 X 10(6) neonatally injected donor cells suffice. In contrast, class II molecules, presented on F1 donor cells having an H-2 I region difference from recipients, can induce tolerogen-specific helper T cell hyporeactivity only when at least 1 X 10(7) neonatally injected donor cells are used, and then only in some of these recipients. Results from another in vitro assay system, taken in conjunction with these data, indicate that the molecular class of the tolerizing disparity, rather than the effector function of the responding cell type assayed, may be the most important factor in controlling the ease with which neonatally induced alloantigen tolerance can be achieved. In each type of tolerance described here, the hyporeactivity seen is antigen specific, in its induction and its expression; the implications of this fact for considerations of possible mechanisms of tolerance maintenance are discussed.

Aging↗