IMMUNOLOGY OF 2-ACETYLAMINOFLUORENE-INDUCED RAT MAMMARY ADENOCARCINOMAS

The immunogenicities of 11 rat mammary adenocarcinomas induced with 2‐acetylaminofluorene (AAF) have been studied. Attempts were made to induce tumour‐specific immunity in syngeneic female rats, following treatment with heavily irradiated tumour or surgical removal of developing subcutaneous tumour grafts. Resistance was evoked against only two tumours and this was extremely weak. With the others, no resistance against the immunizing tumour could be demonstrated, even though the tests were made highly sensitive by the use of inocula of as few as 103 cells in pre‐irradiated hosts. Sera from rats immunized against six of the tumours were tested against viable cells of the immunizing tumour in an immunofluorescence test. In no case did tumour antisera give a positive reaction with the tumour cells, although allogeneic isoantisera consistently gave strongly positive reactions. The results are interpreted as showing that AAF‐induced rat mammary adenocarcinomas are deficient in tumour‐specific transplantation antigens. Copyright © 1969 Wiley‐Liss, Inc., A Wiley Company