Characterization of the cytolytic activity of a cloned antigen-specific T suppressor cell derived from a tolerant CBA/J mouse.

The antigen-specific T suppressor cell clone HF1 isolated from a CBA/J mouse made tolerant by low doses of bovine serum albumin has suppressive and cytolytic activity. The analysis of the latter gave the following results. Natural killer (NK)-sensitive YAC-1 (H-2a) and RBL-5 (H-2b) target cells are lysed whereas other NK targets, like EL4 (H-2b) or the human K562 cell line are resistant. Cytolytic activity is not antibody mediated. Its inhibition by sugar phosphate or monoclonal antibodies against LFA-1 antigens is such that HF1 can neither by typed as T killer nor as NK cells. It seems to represent a distinct T lymphocyte type.