The effect of a synthetic double-stranded RNA on IgC1 and IgE production by guinea-pigs. A comparative study with lipopolysaccharide.

The effect of synthetic complexes of polyribocytidylic acid (poly-IC) on the production of homocytotropic antibodies by guinea-pigs was studied. It was observed that poly-IC has a definite adjuvant effect on the production of both IgG1 and IgE. The adjuvant effect was present when poly-IC was injected 24 hours after the antigen, but was absent when the polynucleotide was injected 48 hours after the antigen. In comparison with lipopolysaccharide (LPS) the adjuvant effect of poly-IC was weaker, more than 0.5 mg/kg of this polynucleotide being required to show an adjuvant effect, whereas only 20 mug/kg of LPS was enough to show a positive adjuvant effect. Furthermore, considerably less antibody was detected in the animals stimulated with the polynucleotide.