Augmentation of NK cell activity and proliferation in cultured lymphocytes of leukemic patients by monoclonal antibodies CD3 and interleukin-2.

The aim of the present study was to induce NK cell activity in peripheral mononuclear cells (PMNC) of normal individuals or of leukemic patients. For this purpose, monoclonal antibodies (mAbs) anti-CD3 (MEM 57, OKT 3 and MEM 92), anti-CD59 (MEM 43) and anti-CD43 (MEM 59) were tested. MEM 43, MEM 59, MEM 57 and OKT 3 stimulated markedly the NK activity in fresh isolated PMNC of normal individuals, whereas the cytotoxicity in 3-day cultivated PMNC was enhanced only by MEM 57 and OKT 3. In comparison to interleukin-2 (IL-2), MEM 57 and OKT 3 induced less PMNC cytotoxicity but more cell proliferation. MEM 92 (anti-CD3, IgM) compared to MEM 57 or OKT 3 (anti-CD3, IgG) did not show any effect on both reactions mentioned above. PMNC of untreated leukemic patients exerted very negligible NK cell activity. Following 3-day culture of leukemic PMNC with OKT 3 or IL-2 the anti-K 562 cytotoxicity was markedly enhanced. In some cases the stimulating effect was more pronounced by IL-2, in others by OKT 3. Nevertheless, the best effect was gained in 7 out of 12 patients using a combination of IL-2 and OKT 3. On the other hand, OKT 3 did not synergize with IL-2 in normal PMNC culture.