Cytolytic T cells recognize the two amino-terminal domains of H-2 K antigens in tandem in influenza A infected cells.

We have genetically engineered three alleles of the K locus of the major histocompatibility complex (MHC) of the mouse. These novel hybrid H-2K genes were introduced into mouse 1T 22-6 cells (H-2q), and their products were shown to be expressed on the cell surface. The hybrid H-2 K antigens were examined for their ability to function as restricting elements for cytotoxic T lymphocytes during influenza A infection. Both the alpha 1 and alpha 2 domains of the Kd antigen were required for T cell recognition. This implies an important role for "conformational determinants" on H-2 antigens acting as restricting elements. The cytoplasmic domain of the Kb antigen is not phenotypically important for recognition by T cells.