In vitro effects of Rubella virus, strain RA 27/3, on human lymphocytes. II. Specific antigen stimulation in relation to Rubella haemagglutination inhibition antibodies.

Investigation has been made of the specific in vitro stimulation of human lymphocytes by live or inactivated rubella virus of the strain RA 27/3. The thymidine incorporation of lymphocytes from blood donors with different serological immunity against rubella was measured following incubation with the viral antigens. UV-inactivated rubella virus caused a moderate degree of stimulation of lymphocytes from seropositive individuals. On the other hand, live rubella virus stimulated lymphocytes from donors with low titres of anti-rubella HI-antibodies but not lymphocytes from donors with high antibody titres. Possible explanations for this discrepancy are discussed.