Lewis lung tumor system as a model for studying the immune function in syngeneic in equillibrium allogeneic chimeras

Lewis lung tumor (LLT) passaged in F1 hybrids of the original C57B1/6 strain, where it arose spontaneously, is rejected by allogeneic SWA (Swiss albino) mice. However, aggregation chimeras derived from these SWA mice and the F1 hybrids of C57B1/6 developed an increased growth of primary tumor and reduced number of metastases when compared with the F1 hybrids. In the present study LLT passaged in C57B1/6 mice is not rejected by SWA mice. It is demonstrated that in aggregation chimeras now derived from two strains both taking the tumor, primary tumor growth was enhanced and the number of metastases reduced as in the former experiment. The tendency of reactions of lymphatic orgains in chimeras to tumor burden was comparable with the SWA and F1 hybrid (C57B1/6 multiplied by SWA and SWA multiplied by C57B1/6) recipients' response. Furthermore, chimeras had the highest spleen enlargement. Possible alternations in immune functions of chimeras due to their differing genotype combination are discussed in the LLT model.