Effect of antibodies to granular perforin and calmodulin on the activity of natural killer cytotoxic factor.

It was previously established that the cell death induced by natural killer cytotoxic factor (NKCF) is a complex calcium-dependent two-stage process. In the initial stage, during the first 30 min of incubation of NKCF with target cells, pore formation on the surface of the target is observed, together with temporary membrane damage. The second stage cytolytic activity occurs after a 3 h latent period, reaches maximum at 24 h, and leads to cell death. A more detailed analysis of the NKCF-dependent lysis of cells was carried out in a study of the action of antibodies to granular perforin and calmodulin on this process. It was established that pore formation in the membrane after 30 min and cell lysis over the next 24 h are interdependent stages of a single process. The interaction of antibodies to perforin with the perforin-like protein of NKCF led to blockage of pore formation and to subsequent inhibition of target cell lysis. Treatment of NKCF with antibodies to calmodulin gave rise to the appearance of pore-forming activity in the first 30 min of incubation with target cells and to the subsequent acceleration of cell lysis over the next 24 h.