The effect of T cell independent and cross-reactive antigen on the immune response to pneumococcal conjugate vaccination.

The effect of priming with various antigens on subsequent vaccination with the pneumococcal conjugate vaccine (CPV) was determined using BALB/c mice. Priming with pneumococcal polysaccharide or cross-reactive polysaccharide did not inhibit the IgG response to CPV immunization. Additionally, live intranasal colonization by Streptococcus pneumoniae or cross-reactive organism resulted in higher IgG responses to CPV. These results suggest that colonization elicits immunological memory capable of boosting the immune response to CPV.