UBC Theses and Dissertations
The effect of continual antigenic stimulation on the immune system of mice McMaster, William Robert
The effect of continual antigenic stimulation on the immune system of mice was studied using two different experimental approaches. A GVHR was induced in Fi mice by the injection of parental spleen cells at weekly intervals. Several weeks later the spleen cells of mice undergoing a GVHR were shown to be immunosuppressed as their in vitro responses to the mitogens Con A and LPS were substancially lower than control animals. The serum from these treated mice was also immunosuppressive to normal spleen cells. The proliferative response to Con A and allogeneic cells of normal: syngeneic, allogeneic, and parental spleen cells was 90% suppressed when GVH serum was added in comparison to the addition of normal serum. Similarly, the in vitro antibody response to a T dependant antigen was impaired; however, the antibody response to a T independant antigen was not impaired. These results indicate that T cell functions are more sensitive than are B cell function to immunosuppressive factors in the serum of mice undergoing a GVHR. The serum was fractionated by gel filtration on a Bio-Gel P-200 column. The inhibitory material in GVH serum eluted in the immunoglobulin fraction of serum which indicate that it has a molecular weight of 150,000 or greater. The second approach studied involved continual allogeneic stimulation. Parental type mice were injected at five day intervals with Fi spleen cells in order to induce a HVG reaction. After several injections the spleen cells from these mice were tested in vitro. The spleen cells from HVG mice responded the same as normal spleen cells to the mitogens Con A and LPS. The spleen cells from HVG mice showed an enhanced in vitro antibody response as compared to normal spleen cells. This enhancement was attributed to the allogeneic effect. This series of experiments have shown that the induction of a GVHR in mice can later lead to immunosuppression and production of immunosuppressive factors in the serum of these mice. The induction of a short term HVG reaction has no adverse effects on the immune system except for enhancing an antibody response. It is possible that a more prolonged HVG reaction would parallel the immunosuppression observed in mice undergoing a GVHR.
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