Kinetic analysis of Qa-1-specific cloned cytotoxic T lymphocytes: lytic parameters and evaluation of cellular inhibition.

A kinetic analysis of lysis assay was used to compare cytolysis of target cells expressing different allelic Qa-1 determinants by a Qa-1b-specific cytotoxic T-lymphocyte clone (CTL). Although this clone specifically recognized the Qa-1b determinant it also recognized the Qa-1c and Qa-1d determinants to a lesser extent. The maximum rate of lysis against Qa-1b targets was 10-fold faster than against Qa-1c or -1d targets. The affinity of the CTL clone for the Qa-1b and -1c target cells was the same, but significantly less for Qa-1d targets. The pattern of inhibition observed for target and inhibitor cells in these experiments was competitive. These studies demonstrated a greater similarity between the Qa-1b and -1c determinants, compared with Qa-1d. Kinetic analysis of lytic reactions allowed for quantitative evaluation of the similarities and differences between various target cell populations to an extent not possible using conventional cell-mediated assays.