Induction of group 17 specific antibodies by pneumococcal type 17F and 17A polysaccharide vaccines

Pneumococcal capsular polysaccharide group 17 contains two distinct serotypes, 17F and 17A. Pneumococcal group 17 is present in the licensed 23 valent polysaccharide vaccines. One such vaccine contains type 17A, while the other vaccine contains type 17F. The purpose of these studies was to determine the extent of cross-protection that could be expected, as both type 17F and 17A cause disease. The antibody responses of one group of adults to a vaccine containing type 17F was compared to that of another group that received a type 17A containing vaccine. By ELISA the 17A vaccine induced more cross-reactive antibodies. Opsonophagocytic antibodies are a good predictor of protection and both vaccines induced antibodies opsonic for both 17F and 17A. We conclude that either 17F or 17A will provide similar protection against group 17 disease.