Cell surface antigens of chemically induced sarcomas of murine origin

Chemically induced sarcomas of murine origin are characterized by the expression of unique tumour-specific transplantation antigens. Their nature and the genetic basis of their antigenic diversity are unknown. Numerous attempts have been made to relate these antigens to products of known polymorphic gene families. A serological analysis of cell-surface antigens of sarcomas was initiated on the premise that serologically defined unique tumour-specific antigens would be related to tumour-specific transplantation antigens. This analysis led to the serological definition of two noncross-reacting tumour-specific antigens on two antigenically distinct BALB/c sarcomas, Meth A and CMS4. Assignment of the gene(s) involved in expression of the Meth A antigen to the distal region of chromosome 12, the same region encoding Igh, raised the possibility that genetic elements responsible for antibody idiotype could be involved in the antigenic diversity of tumour-specific transplantation antigens. Although several studies indicate a concordant expression of the Meth A and the tumour-specific transplantation antigen, the Meth A tumour-specific transplantation antigen identified as an 82,000-Da protein does not express the serologically defined antigen. This is in contrast to the Zajdela hepatoma of rat origin, where a serologically defined tumour-specific antigen is related to the tumour-specific transplantation antigen. Whether the serologically defined Meth A antigen has tumour-specific transplantation antigen activity is not presently known.