ANTIBODIES TO PNEUMOLYSIN AND PNEUMOCOCCAL CAPSULAR POLYSACCHARIDES IN MIDDLE-EAR FLUID OF CHILDREN WITH ACUTE OTITIS-MEDIA

Antibodies to pneumococcal pneumolysin and capsular polysaccharides we re measured by enzymeimmunoassay in 169 acute phase middle ear fluid s amples of 116 children with acute otitis media. Antibodies to pneumuco ccal pneumolysin were detected in 84% and to capsular polysaccharides in 50% of the MEF samples. The Ig class detected most often was IgA to both types of pneumococcal antigens. and it was present in MEF even w ith non-detectable levels of serum IgA of the same specificity. 59% of the MEF samples positive for IgA to pneumolysin were also positive fo r secretory component of the same specificity, and 53%, of IgA to caps ular polysaccharide pool (containing serotypes GB, 14. 19F, and 23F). respectively. This suggests both leakage of specific IgA from serum to the middle ear and local production of it. In contrast, specific IgG was detected in MEF only with concomitant IgG in serum, Antibodies to pneumolysin occurred in no relation to bacterial findings in MEF. On t he contrary. IgG class antibodies to capsular polysaccharides, most li kely serum-derived, were detected less often in MEF samples positive f or pneumococcus than for other bacteria.