On the nature of transplantation immunity in the adenovirus tumor system.

The existence of a virus-induced, virus-specific transplantation, antigen in adenovirus 12-induced CBA mouse tumors was demonstrated. The antigen is virus-specific, but not related to structural virion or T antigens. It is a weak antigen, and required immunization with whole, infectious adenovirus 12 to produce considerable immunity. Comparable immunity could not be achieved with homologous cellular or subcellular materials, but some indication of enhancement was produced with low tumor dose. Immunization required at least 2 wk and was mediated by immune lymphoid cells. Serum of immunized animals showed no demonstrable cytotoxicity or enhancement. Animals immunized with virus and Freund's adjuvant showed diminished transplantation immunity, although these animals were actively immunized against adenovirus type 12 structural virion antigens.