Effects of insulin and transferrin on the generation of lymphokine-activated killer cells in serum-free medium.

We have developed a serum-free medium designated RDSF for the generation of LAK cells based on RD6F medium, which was originally developed as a serum-free medium for the growth of myeloma and hybridoma cells. The cytotoxic activity of LAK cells generated in RDSF against Raji, K562 and oral cancer cells, is 3-4 times that of LAK cells generated in medium containing 10% human type AB serum. RDSF medium consisted of nutrient mixture supplemented with transferrin, 2-aminoethanol, 2-mercaptoethanol, sodium selenite and interleukin-2. In this study, we have found that insulin which has been shown to be the most important polypeptide hormone in serum-free media for animal cells, inhibited the generation of cytotoxic activity of LAK cells cultured from peripheral blood lymphocytes. In addition, we found that transferrin was an essential component for the growth and generation of LAK cells in serum-free culture. These results suggest that RDSF may be useful in adoptive immunotherapy for cancer as well as for studying factors involved in the growth and differentiation of LAK cells.