ABSTRACT
Physico-chemical and biological properties of an interferon inducer, a natural double-stranded RNA (dsRNA) obtained from RNA-genome bacteriophage-infected E. coli are described. Three independent methods i.e. sedimentation analysis, gel chromatography, and direct measurement of electronograms, were used to determine an average length of dsRNA molecules which was found to correspond to about 432 nucleotide pairs. dsRNA melting temperature in 0.15 M NaCl is 103 degrees C, and the resistance to RNase A is above 85%. Additional purification of the preparation by the methods eliminating bacterial endotoxin and other possible admixtures does not decrease acute toxicity of dsRNA. The influence of dsRNA on the cytolytic activity of natural killers (NK) in normal subjects and patients with viral diseases of the liver was demonstrated. dsRNA enhances the activity of NK in normal subjects as well as in patients with acute virus hepatitis B in the abatement stage of the disease and in patients with chronic persisting hepatitis. At the peak of acute virus hepatitis B NK stimulation was detected in only 40 +/- 16% of the patients. In patients with chronic active liver diseases dsRNA enhanced NK activity in 50 +/- 22% of cases. A similar effect on NK cell activity is exerted by human leukocyte interferon.
