Lymphoblast proliferation and humoral antibody response after rubella vaccination.

Twenty-eight sero-negative young women were vaccinated with RA 27/3 or HPV-77/DE5 strain live attenuated rubella vaccine. Haemagglutination-inhibiting antibody developed in all but one of the subjects. Rubella-specific IgM antibodies were demonstrable 3–6 weeks after vaccination. Complement-fixing and platelet-aggregation antibodies were more often detectable after RA 27/3 than after HPV-77/DE5 vaccination. After vaccination the blood lymphoblast count increased with a peak at 2 weeks. In one subject no humoral antibody response was detectable but even in this case there was a lymphoblast response. A marked increase in blasts was detected in a single case of natural rubella infection. In the vaccinated subjects the tuberculin skin test did not reveal suppression of delayed hypersensitivity 3 weeks after vaccination, nor was there a change in the responsiveness of lymphocytes to PHA 2 weeks after vaccination. No significant decrease in platelet count was seen in any of the subjects.