Derivation of cells with lytic activity against fresh and cultured tumors from human bone marrow

We studied the derivation of cells with lymphokine-activated killer (LAK) cell activity from human bone marrow cultures. In these experiments, 26/26 specimens of human bone marrow obtained from sternum, iliac crest, rib, and humerus cultured with IL-2 (1000 U/cc) under varying conditions were able to generate LAK activity. LAK activity obtained from bone marrow mononuclear cell cultures (BMMC) was observed only with exposure to IL-2. Peak LAK activity against fresh melanomas and renal cell carcinoma and sarcomas was obtained usually by the second or third week in culture and could be maintained in some instances for greater than 28 days. Parallel experiments comparing autologous peripheral blood lymphocytes (PBL) cultured under identical conditions and tested simultaneously with BMMC demonstrated comparable LAK activity. T-cell depletion using sheep red blood cell rosetting and density separation on discontinuous gradients did not significantly enrich for a population with enhanced LAK activity. The use of irradiated Epstein-Barr virus-B-cell feeder lines significantly enhanced generation of LAK activity from BMMC when compared to controls (P less than 0.006). Conditioned media from PHA-stimulated 2-day and 4-day PBL cultures, 4-day mixed lymphocyte cultures, and 3-day LAK cultures did not consistently increase the growth or lytic activity of BMMC cultures grown in the presence of IL-2 (1000 U/cc). Phenotypic analysis of BMMC cultures after culture with IL-2 with lytic activity revealed mixed populations with mature T cells (CD3) and null cells (CD2+/CD4- and Leu 19+/Leu 7+) with decreased myeloid precursors (My 9+).