IMMUNOGENIC PROPERTIES OF RETROVIRAL PROTEIN P15E FROM DRUG-TREATED MURINE MASTOCYTOMA P815

A triazene-xenogenized tumor sub-line was derived from the mouse masto cytoma cell line P81 5 following several transplant generations in viv o on DTIC. The highly immunogenic P815/DTIC variant line expressed new CTL-defined antigens. Novel antigens were also detected by antibodies in immunoprecipitation and by Western blot analysis. Upon immunopreci pitation of metabolically labeled cells, one such variant-specific 20- kDa antigen was shown to be related to retroviral envelope protein p15 E. When injected intrasplenically into recipient mice, the electroblot ted nitrocellulose-bound 20-kDa antigen resulted in increased frequenc y in CTL precursors to P815/DTIC cells. In addition to previous data i n the L5178Y/DTIC tumor-model system, these data suggest that expressi on of aberrant, retrovirus-related proteins may be a common finding in different parental tumors xenogenized by triazene treatment. (C) 1993 Wiley-Liss, Inc.