Sex differences in antibody- and cell-mediated immune response to rubella re-immunisation

Antibody (AMI) and cell-mediated (CMI) immunity to rubella virus (RV) were evaluated in healthy adolescent males (n = 11) and females (n = 28) undergo ing routine reimmunisation with RA27/3 strain RV as a component of measles- mumps-rubella (MMR) vaccine, Blood samples were collected just before and a t 2, 4 and 10 weeks after MMR While there were no sex. differences before M MR and at week 10 after vaccination, levels of specific IgG determined by w hole RV enzyme immunoassay were found to be significantly higher in males a t weeks 2 and 4, suggesting brisker onset of recall AMI, Analysis of RV pro tein-specific IgG by immunoblot assays also revealed that while there were no notable sex differences in the distribution of E1-specific antibodies, m ore males produced E2-specific antibodies whereas more females produced C-s pecific antibodies after immunisation. Analysis of CMI with whole inactivat ed RV and a panel of RV synthetic peptides in lymphocyte proliferation assa ys revealed a brisker onset of CMI in males which paralleled that observed for AMI, The numbers of RV antigens recognised by males were significantly higher at weeks 2 and 4, Also, mean and median stimulation indices measured at weeks 2 and 4 for certain peptides, including two known to contain over lapping antibody neutralisation domains and T-cell epitopes, E1(213-239) an d E1(254-285), were also found to be significantly higher in male subjects. These observations suggest that there are hormonal influences on RV-specif ic immunity which might result in differential handling of RV and, hence, m ay partially explain why females are more predisposed to adverse outcomes o f rubella infection and immunisation.