Pneumococcal carriage and otitis media induce salivary antibodies to pneumococcal surface adhesin A, pneumolysin, and pneumococcal surface protein A in children

Local antibodies probably contribute to defense against Streptococcus pneum oniae. This study examined whether pneumococcal carriage and acute otitis m edia (AOM) induce mucosal antibodies to potential vaccine candidates pneumo coccal surface adhesin A (PsaA), pneumolysin (Ply), and pneumococcal surfac e protein A (PspA). IgA to all 3 proteins was detected by EIA in saliva of 329 children at ages 6, 12, 18, and 24 months and of 17 adults. A higher pr oportion of IgA-positive samples and higher antibody concentrations were se en in children with pneumococci-positive cultures of nasopharyngeal samples or middle ear fluid than in children with all cultures negative for pneumo cocci. The strong correlation between IgA and the presence of the secretory component suggests that the IgA was secretory. The findings indicate that pneumococcal carriage and AOM induce local production of anti-PsaA, anti-Pl y, and anti-PspA antibodies early in life.