S. L. Rabasa

Growth of sarcoma 180 in splenectomized mice bearing diffusion chambers containing spleen or tumor cells

Sarcoma 180 (S-180) is 100% lethal in BALB mice and leads to spontaneous regressions in AKR, A and inbred Rockland mice. Splenectomy significantly increases the regression rate of S-180 in these strains when performed either 7 days before or after the tumor challenge. That this effect is specific is suggested by the fact that partial hepatectomy has no effect and that the growth of 3 other sarcomas, either syngeneic or allogeneic, remains unaffected by splenectomy. In BALB mice, diffusion chambers with 0·22 μ filters, enclosing viable syngeneic spleen cells or S-180 cells, introduced intraperitoneally at the time of splenectomy and 7 days before S-180 challenge, are both capable of reversing the effect of splenectomy. This is not obtained in control groups including either diffusion chambers enclosing cells from a different sarcoma or empty chambers. Hypothetically these data would indicate that S-180 cells trapped within the diffusion chambers would permit the elaboration of humoral antibodies in the absence of the spleen. Upon tumor challenge, 7 days later, the presence of these antibodies would alter the temporal relationship between the humoral and cellular immune responses, favoring progressive tumor growth.