Long-Term Growth and Expansion of Ril-2 Activated Nk- Cells for Cancer Therapy

Incubation of human peripheral mononuclear blood leucocytes (PMBL) with high levels of recombinant interleukin-2 (rIL-2) results in the generation of cells cytotoxic for fresh tumors and cultured tumor cell lines. Each symbol represents cells obtained from one patient and tested on day 0 prior to culture with rIL-2 and at various days after incubation in rIL-2-containing medium. The frequency of CD3 positive cells was high on day 0 and generally showed a declining tendency during the culture period. However, considerable variability in the decrease of CD3 was observed from patient to patient. CD 16 positive cells are believed to be the effector cells for the so-called lymphokine-activated killer phenomenon. The long-term culture of PMBL in rIL-2 may be of advantage over short-term activation protocols. If the Leu¹¹⁺ cells are in fact the mediators of the therapeutic response, the long-term culture generates up to 6 times more effector cells.