The cell surface phenotype of a naturally occurring human suppressor T-cell of restricted specificity: definition by monoclonal antibodies.

A series of murine monoclonal antibodies was used to characterize the surface phenotype of a naturally occurring E+ B14-specific suppressor cell present in the blood of a patient with recurrent superficial bladder carcinomas. This suppressor T cell is different from the few naturally occurring suppressors of MLC reported by others in that its function does not require HLA-D compatibility with the cells being suppressed. This patient's T cells had decreased proportions of T3+, 10.2+, 9.3+, and T4+ cells, a normal proportion of T8+ cells, and a markedly increased proportion of Ia-positive cells. The MLC-suppressor assay was used to test the functional activity of cell populations selectively depleted by treatment with monoclonal antibodies and C or enriched by panning. The B14-specific suppressor T cells in this patient expressed T cell markers recognized by monoclonal antibodies 9.6, T3, and the T cell subset marker identified by OKT8 (T8+) but not the subset marker identified by OKT4 (T4-). Ia antigens were present on a substantial portion of these suppressor T cells. Thus, this unique, naturally occurring suppressor T cell has a phenotype similar to that of other T suppressor cells in humans, adding validity to the concept of functionally distinct T cell compartments in human blood.