[Lymphokine-activated killer (LAK) adoptive immunotherapy: optimal method for large-scale LAK induction]

Adoptive immunotherapy with lymphokine-activated killer (LAK) cells shows promise as a treatment for malignant disease, but one of the difficult problems associated with the LAK therapy is the method to induce 10(11) to 10(12) of LAK cells. In a study for optimal LAK induction, monocytes separated with counterflow centrifugal elutriation markedly augmented LAK cell induction from lymphocytes in spite of having no cytotoxicity when cultured alone; LAK activity was sufficiently induced from mononuclear cells (MNC) containing approximately 20% of monocytes; LAK activity was induced depending on the serum concentration, and at least 5% of human AB serum in RPMI 1640 was referred to induce optimal LAK activity; and roller bottle was preferable to tube or flask especially at higher MNC density. We concluded that roller bottle with 4 X 10(6) cells/ml of MNC suspended in 1 liter of RPMI 1640 containing 5% AB serum would be the optimal condition for large-scale LAK induction, and administration of LAK cells on the 3rd and 4th day of culture is favorable for weekly performance of LAK adoptive therapy.