A monoclonal antibody blocking human T cell function

Abstract

The possible functional role of T cell surface antigens defined by monoclonal antibodies was investigated. Five monoclonal anti‐T cell reagents as well as an anti‐la and anti‐β 2‐microglobulin antibody were examined for their effect on T cell function. It was shown that an antibody termed anti‐T3, reactive with all peripheral T cells, blocked T cell proliferative responses to soluble and cell surface antigens. This inhibition was seen when T lymphocytes were treated with as few as 10 4 anti‐T 3 molecules per cell. Although anti‐T 3 could block the generation of cytotoxic T cells in mixed lymphocyte culture, once generated, anti‐T3 had no effect on cytotoxicity. In addition, anti‐T 3 abrogated the ability of T cells to provide help to B cells in a pokeweed mitogen‐driven immunoglobulin system. More importantly, these functional effects were not seen with the other monoclonal antibodies. Both the appearance of this antigen in intrathymic ontogeny and its critical role in T cell function suggests that the T3 molecule is related to an important antigen recognition receptor or cell‐cell interaction molecule.