SHARED T-CELL-DEFINED ANTIGENS ON INDEPENDENTLY DERIVED TUMORS

We report that a subset of tumors independently derived from a cloned line of contact-inhibited, non-tumorigenic murine fetal fibroblasts co nfer cross-protective immunity against each other in vivo. Concordant with the in vivo cross-protection, cytolytic T cell clones from mice i mmunized with one of these tumor lines specifically lyse the three oth er lines in the same set but do not cross-react with either the nontum origenic parental line or another similarly derived tumor line represe nting a different antigenic profile. This and other recent evidence fo r shared expression of tumor rejection Ag contrasts with the antigenic diversity previously described for chemical- and radiation-induced tu mors. In the interpretation of such data it is essential to distinguis h between Ag expressed in association with the transformation process and Ag induced by random mutation of already transformed cells.