H-2 typing of RBL-5, TLX/9 tumour cells and L929 fibroblast.

The H-2 specificities in two different H-2b tumour cells (TLX/9 and RBL-5) and a fibroblast line L929 (H-2k) have been studied. Tumour cells were passaged intraperitoneally in syngeneic mice and fibroblast was kept in vitro at 36 degrees C. The typing was performed by means of a postlabelling microradioassay for actively growing cells and 28 H-2 alloantisera of restricted specificity defining private H-2K, H-2D and public antigens. Unexpected reactions in disagreement with H-2 genetics were detected in both tumours but not in fibroblast line. The latter shed C-type particles whereas RBL-5 did not. The cytotoxicity of the alloantisera was quantitatively absorbed by normal lymphoid cells, although some extrareactivities were due to other antibodies present in the sera. RBL-5 grew in mice of different H-2 haplotypes with the same intensity as in syngeneic animals.