Fibronectin as a compensating factor in the natural cytotoxicity system in interferon-dependent immunodeficiency

The cytotoxicity of natural killer cells (NK) against3H-uridine-labeled target cells (TC, human erythromyeloleukosis cells K-562) and the intensity of conjugate formation in the NK:TC system in the presence of γ-interferon, C-reactive protein, and human fibronectin are studiedin vitro in 14 patients with multiple sclerosis. It is shown that γ-interferon and C-reactive protein decrease the cytotoxic activity of NK with a simultaneous stimulation of conjugate formation in the NK:TC system. The correlation between the studied parameters becomes weaker. Human fibronectin induces collateral changes in the activity of NK and in the number of effector:target conjugates formed in the natural cytotoxicity reaction.