Immune responses to H-2Kd antigen expressed by recombinant vaccinia virus

A recombinant vaccinia virus (VV-H2Kd-6) containing the coding sequence for the murine major histocompatibility complex class I antigen H-2Kd has been constructed and used to express H-2Kd on the surface of infected cells. Vaccinia expressed H-2Kd has been shown to generate an H-2Kd-specific primary cytotoxic T-cell response in mice infected with the recombinant virus and to stimulate an H-2Kd-specific cytotoxic T-cell response in vitro. Cells infected with the recombinant virus acted as targets for specific lysis by appropriate alloreactive cytotoxic T cells, albeit relatively inefficiently when compared with alloreactive recognition and specific lysis of H-2Kd-containing P815 cells. However, H-2Kd expressed by the recombinant virus was recognized efficiently as a restricting element in association with vaccinia virus antigens, while lysis of VV-H2Kd-6-infected L929 (H-2k) cells by CBA/H (H-2k) anti-C3H.OH (H-2KdDk) cytotoxic T cells was comparatively weak. These data suggest that there are quantitative or qualitative differences, or both, between H-2Kd expressed by vaccinia virus and cells of the H-2d haplotype. Qualitative differences have not been demonstrated but cannot be excluded.