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.

[The effect of catalytic subunit of cAMP-dependent protein kinase on the activity of cytotoxic factor from natural killer cells].

The catalytic subunit of cAMP-dependent protein kinase modifies proteins of NKCF. Several proteins of the treated NKCF can be labelled with 32P. Treatment of NKCF with protein kinase enhance the cytotoxicity of NKCF.

Separation of the pore-forming and cytotoxic activities from natural killer cell cytotoxic factor.

The influence of Ca2+ on the cytotoxic activity of natural killer cell cytotoxic factor (NKCF) was analyzed. When the natural killer susceptible cell line K562 was exposed to NKCF in the presence of 5 mM Ca2+, two peaks of cell damage were found. The first peak was observed after 30-40 min of incubation as a result of pore formation on the surface of target cells.

[Detection of a perforin-like protein from the soluble cytotoxic factor of natural killer cells].

The protein composition of the cytolytic factor (NKCF) secreted by natural killer cells was analyzed. Natural killer cells were isolated from spleens of nude rats and purified in the Percole gradient. SDS-PAAG analysis of NKCF revealed the presence of major proteins with an approximate molecular weight of 62-67 kDa.