Syngeneic and allogeneic mouse lymphoma antisera: specificity, reaction with fetal antigen and protective capacity.

Vaccination with modified lymphoma cells produced highly specific antisera in syngeneic murine hosts. These were C3H/HeJ anti-6C3HED and BALB/cJ anti-P1798. These antisera gave positive membrane immunofluorescence tests with the corresponding tumor cells as well as with drug-resistant cells derived from the parental line. Immune BALB/cJ, but not immune C3H/HeJ, antiserum was cytotoxic in the presence of complement. The antisera did not cross-react with the opposite tumor, Moloney virus-induced YAC lymphoma cells, or normal splenocytes from either mouse strain. Both immune and nonimmune sera gave a positive cytotoxic test with Gross virus-induced lymphoma cells, indicating exposure of all the animals to the virus. Mice periodically given booster injections served repeatedly as serum donors; BALB/cJ mice not boosted for 42 weeks after tumor rejection still had circulating anti-P1798 antibodies. Allogeneic C57BL/KsJ anti-P1798 gave immunofluorescence tests with P1798, 6C3HED and normal BALB/cJ lymphocytes; it was cytotoxic for P1798 but not for normal lymphocytes. After absorption with normal BALB/cJ tissues, the serum became highly specific for P1798 but lost it cytotoxicity. Syngeneic and absorbed allogeneic anti-P1798 inhibited fetal liver colony formation on the spleens of irradiated BALB/c mice, indicating reaction with fetal antigen, but 6C3H/HeJ anti-6C3HED did not give similar inhibition. The latter antiserum was used successfully for passive immunization as long as there was excess antibody; BALB/c anti-P1798 did not protect, while C57BL/KsJ anti-P1798 was only marginally protective.