Reconstitution of MHC class I specificity by transfer of the T cell receptor and Lyt-2 genes.

The T cell receptor alpha and beta chain genes donated by an H-2 class I-specific, CD8-dependent cytotoxic T cell clone were transferred, alone or in combination with the Lyt-2 gene, into a class II-restricted, CD4+ T cell hybridoma. Two important points emerged. First, the alpha and beta T cell receptor genes endowed the recipient with the H-2 class I specificity of the donor only if the same cell had also been transfected with the Lyt-2 gene. Second, the functional Lyt-2 molecule was expressed on the transfected cells in the absence of the Lyt-3 polypeptide. These results demonstrate that, besides the T cell receptor, the Lyt-2 polypeptide is the only subset-specific molecule required to retarget a class II-reactive, CD4+ T cell line toward H-2 class I molecules.