Protective serum effects in tumor immunity.

Administration of serum presumed to contain tumor-specific antibodies supported the rejection in immunized mice of syngeneic fibrosarcoma implants which receded after an initial period of s.c. growth. Passive transfer of immune serum to unsensitized mice, sublethally radiated and injected with normal lymph node cells, protected the recipients against i.v. but not against s.c. implantation of syngeneic mammary carcinoma cells. Injection of immune serum assisted the recovery of mice in a state of tumor-induced specific immune depression induced by a large. s.c. mammary carcinoma implant and maintained after surgical cure by injections of serum presumed to contain soluble tumor antigen.