Suppression of natural killer cell activity with radioactive strontium: effector cells are marrow dependent.

NK cells with lytic capacity for Moloney leukemia virus-induced lymphomas have previously been found to occur spontaneously in spleens from nonimmune adult mice. Here, 89Sr-treatment is shown to suppress NK cell function in adult mice without similarly affecting other cell-mediated immune reactions. Thus, selective 89Sr-sensitivity distinguishes NK cells from other killer cell types. The present results indicate that in vivo a functional bone marrow is needed for generation and maintenance of NK activity.