MODULATION OF NK-TARGET CELL-INTERACTION BY A MONOCLONAL-ANTIBODY TO K562 CELLS

In order to identify the target cell recognition molecules involved in the interaction between natural killer (NK) cells and target cells, w e have generated monoclonal antibodies to K562, NK-sensitive target ce lls. After screening by FACScan for the reactivity to K562, one monocl onal antibody (mAb), 4A60, was selected. MAb 4A60 was found to inhibit the proliferation of NK cells induced by IL-2 and K562 cells. However , this monoclonal antibody could not significantly block the conjugate formation between NK and target cells. Moreover, mAb 4A60 only slight ly inhibited the cytotoxicity of NK cells induced by IL-2. Protein ana lysis showed that mAb 4A60 recognized a 53-kDa protein of K562 cells. Taken together, these data suggest that mAb 4A60 inhibits the prolifer ation of NK cells induced by IL-2 and target cells, and the 53-kDa pro tein, a tentative ligand of this mAb of K562, may be involved in this process. (C) 1998 Elsevier Science B.V. All rights reserved.