Investigation of T and natural killer cell function with monoclonal antibodies

The relationship of T cell and natural killer (NK) cell antigens was examined using two monoclonal anti-T cell antibodies. The first--anti-HuLy-m1 (identical to OKTlla), reactive with all E-RFC+ cells and 50% null cells including NK cells--could partially block (greater than 50%) NK activity. The second--anti-HuLy-m2, reactive with T cells, some B cells, and null cells--could stimulate and not block NK activity. The enhancement of NK cell function by anti-HuLy-m2 was not related to interferon stimulation, and neither antibody altered effector:target cell binding. When used together neither augmentation nor blocking effects were observed, indicating different sites of reaction with NK cells. To further explore a possible association between T cell and NK antigens, anti-HuLy-m1 and -m2 were used to investigate certain T cell functions. Neither antibody was mitogenic for peripheral blood lymphocytes (PBLs) or blocked PHA stimulation of PBLs. In addition anti-HuLy-m1 did not inhibit a mixed lymphocyte culture (MLC) but could inhibit cytotoxic T lymphocytes (CTLs) almost as effectively as OKT3. However, anti-HuLy-m2 had no effect in an MLC and showed only minimal inhibition of a CTL assay. These studies demonstrate a relationship of the membrane structure of T cells and NK cells at an antigenic and functional level.