Regulation of large granular lymphocytes and human T cell growth and function by recombinant interleukin 2. II. Acquisition of potent cytotoxic capabilities.

Human large granular lymphocytes (LGL) and T cells were separated from peripheral blood on discontinuous density gradients of Percoll. On a per cell basis, cultured LGL demonstrated higher levels of cytotoxicity against K562 cells than fresh LGL. Cultured T cells acquired cytotoxicity against K562 cells, although they were less cytotoxic than fresh or cultured LGL. During culture, these LGL retained the 3G8, NKH1, OKM1, and OKT10 antigens. Cultured T cells retained the T101 antigen and acquired the OKM1 and OKT10 antigens, but remained negative for the 3G8 or NKH1 antigens. A series of pharmacologic agents known to inhibit cytotoxicity of fresh LGL were also tested for their effects on cultured LGL and T cells. Ethylenediaminetetraacetic acid, known to inhibit the binding of effectors to target cells, inhibited the cytotoxicity of cultured LGL and T cells to the same degree that it inhibited the cytotoxicity of fresh LGL. In contrast, agents which primarily effect post-binding events in cytotoxicity (trypsin, D-mannose 6-P, dexamethasone, prostaglandin E2, anti-LGL granule antibody, and 9.1C3 monoclonal antibody) inhibited the cytotoxicity of cultured LGL and T cells to a much lesser extent than fresh LGL. In addition, on the basis of Michaelis-Menten's kinetic analysis, cultured LGL and T cells developed a higher binding affinity to K562 cells than fresh LGL.