Determination of surface antigens on highly purified human NK cells by flow cytometry with monoclonal antibodies.

Abstract

Highly purified populations of [human] NK [natural killer] cells, T cells, monocytes and PMN [polymorphonuclear cells] were examined with a variety of monoclonal reagents presumed specific for T cells and monocytes. The enriched NK cells showed a pattern of reactivity that was distinct from that of the other 3 populations, sharing antigens with T cells but also sharing antigens with monocytes and/or PMN. A portion of the enriched NK cells expressed OKT8, OKT10 and Lyt-3 antigens that were reported previously as T cell-associated antigens, but no reactivity was seen with other T cell-associated antigens (OKT3, OKT4, OKT6, and OKT11). A portion of the enriched NK cells was positive for OKM1, asialo-GM1 and Ia antigens, which are undetectable on typical T cells but are present on PMN and/or monocytes. By depletion of antigen-positive cells on antibody monolayers, it was found that the activity of the enriched NK population was associated mainly with cells reactive with OKT10, OKM1, and Lyt-3. Although considerable evidence exists to support the T lineage of NK cells, the sharing of some antigens by NK cells and monocytes suggests a possible relationship of NK cells to cells of the monocyte lineage. NK cells are possibly not in either T cell or monocyte lineages and may represent a separate lineage of lymphoid cells.