Functional relationships of Lyt-2 and Lyt-3 expression and T-cell cytotoxicity: a new model system.

We have developed H-2d-specific cytotoxic T-cells from (AKR X B6)F1 mice which express Lyt 2.1, 2.2, 3.1 and 3.2 determinants. Antisera specific for these determinants were used to block cytolytic activity of (AKR X B6) F1-derived cytotoxic T-cells. Blocking of killer activity was demonstrated with Lyt 2.2 + 2.1, Lyt 3.2 + 3.1, Lyt 3.2 + 2.1, or Lyt 2.1 + 3.1, but not Lyt 2.1 + 3.1 or Lyt 2.2 + 3.2, or either antisera alone. The antibody-blocking effects were identical whether tested with 5-day MLC-generated cytotoxic T-cells or cloned H-2d-specific T-cells. The results from these experiments indicate that: 1) blocking of cytotoxicity by antisera to Lyt-2 and Lyt-3 is a cell surface phenomenon since sera to both alleles were necessary to inhibit cytotoxic activity; 2) the expression of Lyt-2 and Lyt-3 does not exhibit allelic exclusion; and 3) that Lyt-2 and Lyt-3 determinants are expressed on the cell surface in a cis, but not trans, configuration.