Human natural killer cells analyzed by B73.1, a monoclonal antibody blocking Fc receptor functions. I. Characterization of the lymphocyte subset reactive with B73.1

TLDR: It is demonstrated that virtually all lymphocytes with K/NK cytotoxic activity are found in the lymphocyte subpopulation bearing the B73.1(+) lymphocyte subset, which corresponds to the lymphocytes subset containing antibody-dependent killer (K) and natural killer (NK) cells.

Abstract: We describe the production of the monoclonal antibody B731, reacting with a subset of human lymphocytes and, in about one-half of the donors, with neutrophilic polymorphonuclear leukocytes In the peripheral blood from normal adult donors, 146 +/- 85% of the lymphocytes react with B731 antibody The B731(+) lymphocyte subset does not bear markers of typical T or B cells and corresponds to the lymphocyte subset containing antibody-dependent killer (K) and natural killer (NK) cells We demonstrate that: a) virtually all lymphocytes with K/NK cytotoxic activity are found in the lymphocyte subpopulation bearing the B731-defined antigen; b) the B731(+) lymphocyte subset bears the combination of antigens known to be present on K/NK cells; and c) there is a positive correlation between the level of cytotoxicity and the actual number of B731(+) lymphocytes in individual donors We also report the distribution of B731(+) lymphocytes according to donor age and tissue types The use of the B731 antibody in quantitating the actual number of K/NK cells and in performing functional studies on spontaneous cytotoxicity is discussed