The effects of immunosuppression on the induction and immunogenicity of chemically induced sarcomas

The induction of chemically induced sarcomas does not appear to be accelerated by immunosuppression with antilymphocyte serum. Tumors induced in immunosuppressed mice contain tumor-specific transplantation antigens of antigenic strength comparable to that of those produced in normal hosts. Transplanted tumors will appear and grow more quickly in ALS-treated mice. Moreover, ALS pretreatment can block the recognition of and response to tumor-specific transplantation antigens.

Evaluation of the Immunosuppressive Properties of Ribonuclease Complexes

Complexes were prepared by bisdiazobenzidine coupling of bovine pancreatic ribonuclease (RNase) and human serum albumin (HSA). These preparations prolonged skin allograft survival in mice and inhibited phytohemagglutinin stimulation of human lymphocytes in vitro. The HSA-RNase complexes that were most active in inhibiting lymphocyte stimulation failed to interfere with immune specific macrophage immobilization. The immunosuppressive potency of HSA-RNase complexes did not correlate with their measurable RNase enzyme activities. Furthermore, HSA-RNase complexes of widely differing immunosuppressive potency could not be distinguished by differences in molecular size or charge.