ANTIBODY-SECRETING CELLS AND THEIR RELATION TO HUMORAL ANTIBODIES IN SERUM AND IN NASOPHARYNGEAL ASPIRATES IN CHILDREN WITH PNEUMOCOCCAL ACUTE OTITIS-MEDIA

Mucosal and systemic antibody responses to pneumococcal capsular polys accharide were studied in 17 children with culture-verified pneumococc al acute otitis media. Serotype-specific antibody-secreting cells (ASC s) in peripheral blood and antibodies in acute and convalescent sera a nd nasopharyngeal aspirates were measured, A polysaccharide-specific A SC response was induced in all subjects. The response was age dependen t, and the dominant antibody class was IgA. Three children >24 months old had >100 IgA-class ASCs/10(6) cells and serum and nasopharyngeal I gA responses; 2 had only a nasopharyngeal IgA response. None of 8 chil dren <24 months old showed a systemic response; however, a nasopharyng eal IgA response was detected in 1. Results suggest that whole pneumoc occi can induce a mucosal polysaccharide-specific antibody response in dependent of the systemic response. Results are also in accordance wit h earlier studies suggesting that the mucosal immune system matures ea rlier in life than does the systemic immune response.