CHARACTERIZATION OF RUBELLA-VIRUS STRAIN DIFFERENCES ASSOCIATED WITH ATTENUATION

A comparison of the phenotypic properties of three rubella vaccines (H PV77/DE5, RA27/3 and Cendehill) and four wildtype (wt(+)) isolates (M3 3, Therien, Thomas and IB2) has been carried out. Differences in growt h characteristics, plaque morphology and temperature sensitivity were identified. In addition differential reactivity of the strains to poly clonal and a monoclonal anti-E1 antibody were found in immunoperoxidas e-staining reactions. The ability of the wt(+) and vaccine strains to infect lymphoreticular cells and chondrocytes, also varied in that the RA27/3 and Cendehill strains were highly restricted in both these cel l types while the wt(+) strains and HPV77/DE5 vaccine grew to high tit er. This biological variation was associated with differences in E1 an d E2 glycoproteins detected on immunoblots.