Natural killing by spleen cells from W/Wv and Sl/Sld anemic mice.

Natural killer cells are mononuclear cells that spontaneously lyse certain tumor cell lines without prior sensitization to the target. In mice, precursors of natural killer cells exist in the bone marrow. Moreover, natural killing is thought to be "marrow-dependent" because irradiation of the marrow in vivo with 89strontium reduces natural killing outside the marrow. We examined natural killing in W/Wv mice, which are congenitally anemic because of a defect in erythropoietic stem cells, and in congenitally anemic Sl/Sld mice, which have a defect in the host environment that prevents effective erythropoiesis. Young (6-8 week) W/Wv mice had reduced levels of natural killing when compared to their normal littermates. The defect in W/Wv mice is discussed in relation to their defects in erythropoiesis. Sl/Sld mice had normal levels of natural killing, demonstrating that the defect in erythropoietic environment does not affect the generation of NK cells.