Class I (H‐2Kb) gene transfection reduces susceptibility of YAC‐1 lymphoma targets to natural killer cells

A “hybrid gene” (MTKb) comprised of the human metallothionein IIA promoter ligated to the genomic sequence of the major histocompatibility complex class I (H-2Kb) gene was subcloned into the expression vector pSV2neo and transfected into the natural killer (NK) cell-sensitive YAC-1 lymphoma. The Kb gene product was readily detectable on the cell surface of G418-resistant transfectants using both Kb-specific monoclonal antibodies and H-2b-specific cytolytic T cells. Unlike control pSV2neo transfectants, MTKb-pSV2neo transfectants were relatively resistant to lysis by NK cells from H-2a, H-2b, H-2k or H-2 (a × b)F1 haplotype mice. These data strongly suggest that the effects of MHC expression on susceptibility to NK cells can be mediated by a single and well-defined class I molecule, Kb.