RNA gene profile variation in peripheral blood mononuclear cells from rhesus macaques immunized with Hib conjugate vaccine, Hib capsular polysaccharide and TT carrier protein

Background: The Haemophilus influenzae type b (Hib) conjugate vaccine has been widely used in children to prevent invasive Hib disease because of its strong immunogenicity and antibody response induction relative to the capsular polysaccharide (CPS) antigen. The data from vaccine studies suggest that the conjugate vaccine contains carrier proteins that enhance and/or regulate the antigen's immunogenicity, but the mechanism of this enhancement remains unclear. Methods: To explore the immunological role of the conjugate vaccine, we compared the immune responses and gene profiles of rhesus macaques after immunization with CPS, carrier protein tetanus toxoid (TT) or conjugate vaccine. Results: A distinct immune response was induced by the Hib conjugate vaccine but not by CPS or carrier protein TT. The genes that were dynamically regulated in conjunction with the macaque immune responses to the conjugate vaccine were investigated. Conclusions: We propose that these genes are involved in the induction of specific immunity that is characterized by the appearance and maintenance of antibodies against Hib.