Cytolytic T cell hybridomas. I. Interleukin 2-independent noncytolytic variants.

Fluorescein-specific cytolytic hybrids were obtained by fusion of an interleukin 2 (IL2)-dependent murine cytotoxic T lymphocyte clone with the thymoma BW5147. The hybrid cells grow and retain cytolytic activity in medium with recombinant IL2. In medium without IL2 rare variants can be selected which grow in the absence of exogenous IL2; these variants are not cytolytic. Anti-IL2 receptor antibodies bind to and inhibit the growth of the cytolytic hybrids while they do not bind to and do not inhibit the growth of the variants. The cytolytic hybrids as well as the non-cytolytic variants produce interferon gamma in response to antigen. These findings indicate that the noncytolytic IL2-dependent variants lost IL2 receptors but not antigen receptors.