Abstract
The neutralization of rubella virus was investigated and shown to proceed by first order kinetics over the first 10 to 15 min. A comparison of the rate constant of neutralization (K) for six strains of rubella virus was carried out over this period of the reaction. Two particularly antibody-sensitive isolates were detected. It was noted that the three strains isolated from in utero infections were poorly neutralized by heterologous antisera when compared to postnatal strains.