Search for Common Antigenicities among Twenty-five Sarcomas Induced by Methylcholanthrene

Summary

The possibility that antigenic specificities may be shared by sarcomas independently induced in mice by methylcholanthrene was explored in 25 tumors. Two modalities of the transplantation test for antigenicity, designated as “multiple challenge” and “multiple immunization,” were used. The first consisted of immunizing mice with one tumor (implantation and excision) and testing in them the rejection of the same and others when threshold cell doses were injected intradermally in different skin sites. It was observed that, while each one of the tumors was clearly rejected in mice immunized with the same tumor line, it grew regularly in mice immunized with each one of the other tumors and in controls. There appeared to be some instances of cross-immunization in a first screening of the 90 possible tests between 10 tumors, but no such cases could be reproduced for any pair of tumors. Therefore, we conclude that each of 10 tumors tested had a different antigenic type. Fifteen tumors were studied in multiple immunization experiments. These consisted of inducing immunity simultaneously with four tumors and challenging this immunity with a single, different one. No stable cross-protection was revealed in 13 out of 14 such tests. One tumor pool was selected, however, which cross-immunized against a different tumor in three out of three tests. It was investigated whether this pool might also protect against four other tumors, with negative results. This study shows the extreme rarity of either totally or partially shared antigenic components between methylcholanthrene-induced tumors, as demonstrated by rejection of tumor cell inocula.