H‐2K^b TRANSFECTION OF B16 MELANOMA CELLS RESULTS IN REDUCED TUMOURIGENICITY AND METASTATIC COMPETENCE

The metastatic B16 mouse melanoma shows a low cell surface expression of H‐2K^b and H‐2D^b class I antigens on cells of both the high‐metastatic line B16‐F10 and the low‐metastatic line B16‐F1. Similarly, newly generated clones of these lines, having different metastatic properties, all express low levels of major histo‐compatibility antigens. One of these clones, the high‐metastatic F10.9, was transfected with H‐2K^b genes to generate H‐2K^b‐expressing transfectants. The resulting clones showed reduced tumourigenicity and a low metastatic phenotype. Unlike the parental cells, H‐2K^b‐positive transfectants are potent inducers and sensitive targets of H‐2K^b‐restricted syngeneic cytotoxic T cells. Immunization of mice with H‐2K^b‐positive transfectants conferred protection against a subsequent challenge with K^b‐positive transfectants but had only a small effect on growth and metastatic spread of parental cells.