Loss of Expression of Transplantation Antigens Encoded By the H-2k Locus on Lewis Lung-carcinoma Cells and Its Relevance to the Tumors Metastatic Properties

The Lewis lung carcinoma 3LL, a C57BL/6 (H-2(b))-originated spontaneous tumor that progresses at the site of transplantation in all mouse strains, produced lung metastases only in mice that shared the H-2D region and the non-H-2 genetic background with the tumor's strain of origin. In vitro cytotoxicity assays revealed that 3LL tumor cells were sensitive to lysis exerted by anti-H-2D(b) immune effector cells but were relatively resistant to lysis by anti-H-2K(b) effector cells. In addition, the 3LL tumor cells could inhibit the anti-H-2D(d) response against EL 4(H-2(b)) target cells but had almost no inhibitory effect on the anti-H-2K(b) response against the same targets. Immunization of C3HeB (H-2(k)) and B10.D2 (H-2(d)) mice with 3LL tumor cells resulted in antisera that could preferentially react with H-2D(b)-positive cells but reacted very weakly with H-2K(b)-positive cells. The results indicate that 3LL tumor cells expressed H-2D(b) cell surface antigens at a high density and seemed to lack membrane glycoproteins that are encoded by the H-2K(b) region.