Structure and function of the rubella virus proteins.

Rubella virus strain HPV-77 contains three structural polypeptides. The nucleocapsid is constructed with the C polypeptide chain, which has a molecular weight of 30,000. The envelope proteins are constructed with two glycopolypeptides; the E1 glycopolypeptide has a molecular weight of 63,000, and the E2 glycopolypeptide has a molecular weight of 45,000-48,000. The nucleocapsid capsomere is approximately 6.2S, has a molecular weight of 130,000, and consists of two disulfide-linked dimers of the C polypeptide. The E1 and E2 glycopolypeptides are associated, but the size and structure of the spike protein have not been determined. Strain-specific antigens were detected within the E2 glycopolypeptide in all of the strains tested. In chronologic serum samples, the titers of antibody to the E2 and C polypeptides were the first to decline. Hybridomas were produced that exhibited hemagglutination-inhibiting and neutralizing activities; however, these functions did not always correlate. Both the hemagglutination-inhibiting and neutralizing antibodies reacted with the E1 glycopolypeptide.