Expression of Human T Lymphocyte Antigens by Killer Cells

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Abstract
K cells, the effectors of antibody-dependent cell-mediated cytotoxicity, were found to express human T but not B lymphocyte antigens detected by rabbit anti-HTLA and anti-HBLA. Pretreatment of effector cells with anti-HTLA+C inhibited ADCC by specifically lysing K cells: no inhibition of ADCC by anti-HTLA occurred when ΔC was substituted for C. By contrast, pretreatment of effector cells with anti-HBLA nonspecifically inhibited ADCC, probably by forming antigen-antibody complexes with HBLA+ cells in effector suspensions: a) treatment with anti-HBLA+ΔC was more inhibitory of ADCC than treatment with anti-HBLA+C, and b) the inhibitory effect of anti-HBLA on ADCC was either eliminated or markedly reduced if effector suspensions were first passed through a nylon fiber column, a procedure that removed most HBLA+ cells without affecting K cell activity. HTLA antigens expressed by K cells and NK cells are the same as HTLA antigens expressed by thymocytes since thymocytes completely absorb the anti-K cell and NK cell reactivity of anti-HTLA.