Cultures of purified human natural killer cells: Growth in the presence of interleukin 2

We have isolated highly enriched populations of LGL, which are virtually devoid of mature typical lymphocytes (as enumerated by morphological and surface antigen analysis using monoclonal antibodies e.g., OKT3) in comparison to T cells which contain greater than 95% sheep erythrocyte-forming cells and are devoid of LGL and $\text{NK}\text{K}$ activities. Both types of cells grew in the presence of crude or partially purified IL-2. Cultures of LGL could be initiated consistently even in the absence of lectins and the cultured LGL retained their characteristic morphology and cytotoxic activity. However, within 7–10 days after initiation, the cultured LGL changed in surface phenotype to become antigenically indistinguishable from cultured T cells.