Primary and secondary autologous mixed-lymphocyte interactions in mice occur via antigens encoded by genes in the I region of the major histocompatibility complex

Cell surface and cell cycle analysis of metal-induced murine T cell proliferation

The heavy metal cations Pb2+, Ni2+ and Zn2+ have previously been shown to induce T cell proliferation which required the presence of both T cells and Ia+ cells at the initiation of culture. This work has examined the ability of these metals to induce cell cycle entry as determined by acridine orange cell cycle analysis. Cell surface phenotype analysis, performed on splenocytes stimulated with optimum metal concentrations (100 microM), indicated that in vitro T cell recovery (growth and/or longevity) was enhanced by Pb2+, Ni2+, and Zn2+. Furthermore, simultaneous examination of cell surface phenotype and cell cycle progression (propidium iodide) indicated that the predominant cell type proliferating in response to these metals was Thy-1.2+. The metals differentially induced L3T4+ and Lyt-2+ cells to enter the cell cycle. The ability of various monoclonal antibodies to modulate metal-induced proliferation was examined. Anti-L3T4a, anti-I-A and anti-I-E blocked metal-induced proliferation. Anti-Lyt-2 only partially inhibited whereas anti-Lyt-1 was stimulatory. These results suggest that recognition of major histocompatibility complex-encoded class II molecules is required for the induction of proliferation by these metals (similar to the autologous mixed lymphocyte response).

Factors in AMLR culture supernatant which mediate the cytotoxic T-cell response to hapten-altered self: interaction with macrophages

Supernatants from autologous mixed lymphocyte reaction (AMLR) cultures mediated the cytotoxic T-cell response in a system containing T cells and mitomycin C-treated, TNP-modified syngeneic thymocytes. No cytotoxic activity developed in the absence of the AMLR supernatants. The removal of thymic adherent cells abrogated the effect of the AMLR supernatants in the generation of cytotoxic cells. AMLR helper activity was restored following the addition of small numbers of splenic adherent cells. These results led to speculation that the AMLR supernatant interacted with accessory cells. Examination of the supernatant revealed significant levels of colony stimulating factor (CSF), and interferon-gamma (IFN-gamma). Functionally, incubation of the AMLR supernatant with P388D1, a macrophage tumor line, resulted in the production of interleukin 1 (IL-1). CSF is a major inducer of IL-1 synthesis. In addition, the AMLR supernatant induced the expression of Ia antigens on the P388D1 cells. IFN-gamma has been reported to mediate this activity. Although both lymphokines were present and appeared to have an effect on macrophages, it was unknown if both were required for cytotoxic T-cell development in this system. Samples of AMLR supernatant were incubated for 10 min at various temperatures. The ability of the AMLR supernatants to mediate cytotoxic T-cell activation was sensitive to incubation at 80 or 90 degrees C. Interestingly, at these temperatures CSF activity in the bone marrow colony-forming cell assay was enhanced. In separate experiments, AMLR culture supernatant was dialyzed against a pH 2 buffer. The induction of IA antigens by these supernatants was sensitive to dialysis at this pH. The similarity with IFN-gamma provides further evidence that this activity was mediated by IFN-gamma in the AMLR supernatants. The ability of the AMLR supernatants to mediate the cytotoxic T-cell response to altered self was also pH 2 sensitive. In contrast, IL-1 inducing capability and bone marrow colony growth, both CSF activities, were not reduced by pH 2 dialysis. Taken together, these data demonstrate a primary role for an IFN-like molecule, present in the AMLR supernatant, on cytotoxic T-cell activation. CSF involvement in this response is suggested by its IL-1 inducing activity, but cannot be definitively proven in the present study.

Helper factors for hapten-self cytotoxic T cells occur in NZB culture supernatants despite deficient AMLR

The ability of helper T cells from NZB mice to produce non-interleukin 2 (IL-2) lymphokines in the autologous mixed lymphocyte reaction (AMLR) was examined. Factors present in normal AMLR culture have been previously reported to mediate the development of a cytotoxic T-cell response to trinitrophenyl (TNP)-modified syngeneic thymocytes. Young NZB mice, like the normal strains, were able to produce the helper factors in the AMLR and to utilize these mediators in the cytotoxic induction system. Old autoimmune NZB mice demonstrated a poor proliferative response in the AMLR and were unable to activate hapten-specific cytotoxic cells in the presence of AMLR culture supernatant from either young or old mice. This was not due to a lack of cytotoxic precursors, nor was it a normal consequence of aging, but may be related to decreased IL-2 production by helper T cells. Interestingly, supernatant from AMLR proliferation deficient old NZB mice contained normal amounts of the AMLR helper factor. These data suggest that AMLR helper factor production is not directly related to the proliferative response and that two different helper-T-cell subpopulations may be responsible for these activities. The production of these mediators in mice which cannot utilize them raise questions about their role in autoimmunity.

Suppression of a polyclonal B-cell response by supernatants from the murine autologous mixed lymphocyte reaction

Previously, we have demonstrated that supernatants from autologous mixed lymphocyte (AMLR) cultures contain helper factors which can mediate the development of a cytotoxic T-cell response to hapten modified self. In the current study, the effect of AMLR supernatants on the humoral response was explored. BALB/C splenic non-T cells produced a large polyclonal antibody response to lipopolysaccharide (LPS), as measured in a Protein A SRBC plaque assay. Surprisingly, syngeneic AMLR supernatants suppressed the LPS-induced generation of plaque-forming cells. The presence of T cells in the stimulated cultures did not affect suppressor activity. The decreased response was not the result of a shift in kinetics, as maximal activity was observed on Day 4, whether or not AMLR supernatants were added. The AMLR culture supernatants were most effective in suppressing the plaque-forming cell response when added at the initiation of culture. AMLR supernatants added after 24 hr of culture resulted in only about 50% of maximum suppression. Supernatants added at 48 or 72 hr had no effect. Interferon-gamma (IFN-gamma) has been detected in AMLR culture supernatant and has been reported to suppress the development of plaque-forming cells in response to LPS. However, it is unlikely the suppressive activity observed in these studies is due to IFN-gamma. Dialysis of the AMLR culture supernatant against a pH 2 buffer for 24 hr or incubation at 70, 80, or 90 degrees C for 10 min, treatments that inactivate IFN-gamma, enhanced suppression. These results suggest that in addition to cytotoxic-T-cell helper factors, the cellular interactions in the AMLR induces the production of a stable mediator(s) which is able to directly suppress B cells at an early stage of their development into plasma cells.

Helper cells in the autologous mixed lymphocyte reaction (AMLR). IV. H-2 restriction and specificity of cytotoxic cells induced by AMLR helper factor

Supernatants from Day 3 cultures of T cells stimulated with syngeneic non-T cells in the autologous mixed lymphocyte reaction (AMLR) contained a T-cell factor distinct from interleukin 2 (IL-2). The AMLR factor could mediate the cytotoxic response of T cells to hapten-modified nonstimulatory syngeneic cells. The activity of this helper factor was H-2 unrestricted. However, the cytotoxic cells which developed in the presence of this factor were H-2 restricted and hapten specific.

Functional aspects of T-cells from patients with non-Hodgkin's lymphoma. Responses to self, TNP-modified self, and alloantigens

Peripheral blood T-cell proliferative responses to autologous non-T cells, Trinitrophenyl-modified autologous non-T cells, and allogeneic lymphocytes were measured in 27 patients with non-Hodgkin's lymphoma (NHL) and 22 age- and sex-matched healthy controls. The NHL patients were not receiving chemotherapy or immunosuppressive drugs at the time of the study and had not received such agents for at least 3 weeks prior to the study. Responses to autologous non-T cells (the autologous mixed lymphocyte reaction [AMLR] ) and to TNP-modified non-T cells were significantly lower in NHL patients than in controls (P less than 0.00002 and P less than 0.0001, respectively), but responses to alloantigens were not significantly different between the NHL patients and the controls (P greater than 0.85). There was no definite correlation of low AMLR responses with disease activity, and normal AMLR responses did not define a subgroup of patients relative to histopathologic findings. The deficiency of AMLR in NHL patients appears to be due to a disturbance in the T-cell compartment.

Helper cells in the autologous mixed lymphocyte reaction. III. Production of helper factor(s) distinct from interleukin 2

In normal mice, the autologous mixed lymphocyte reaction (AMLR) can activate helper T cells that, in the presence of hapten-modified syngeneic cells, can induce a hapten-specific cytotoxic response. Supernatants from AMLR cultures contain a factor(s) that will mediate a cytotoxic T cell response to hapten-altered self. The AMLR factor is effective in facilitating the generation of cytotoxicity only in those cultures containing both T cells and hapten-altered, syngeneic, nonstimulatory cells. Factor production requires an interaction between Lyt-1+23- cells and non-T cells (the T cells synthesize it). The AMLR factor does not appear to be interleukin 2 (IL-2) because it does not activate thymocytes in the presence of antigen, nor does it maintain an IL-2-dependent cell line or function in co-stimulator assays. For the AMLR factor to facilitate the generation of cytotoxicity, thymic adherent cells are a necessary intermediate. These data suggest that the factor recoverable from AMLR cultures acts early in the cytotoxic pathway, before IL-1 production.