title: Serum antibodies to pneumococcal C polysaccharide in children: response to acute pneumococcal otitis media or to vaccination.
abstract: Immunoglobulin class-specific antibody responses to the pneumococcal C polysaccharide (CPS) and to the capsular polysaccharides of types 3, 6A, 18C and 19F were measured by enzyme-linked immunosorbent assay in the sera of children ages 6 months to 7 years. Twenty of these children had acute otitis media caused by pneumococci of type/group 3, 6, 18 or 19, whereas 20 received an injection of 14-valent pneumococcal capsular polysaccharide vaccine. Many of the children in both groups had large concentrations of IgG and/or IgM class anti-CPS antibodies in their first serum sample. Both the infection and the vaccine elicited anti-CPS responses in all three immunoglobulin classes, most notably IgA. The pneumococcal capsular polysaccharides used as antigens in the enzyme-linked immunosorbent assay were found to contain CPS in amounts ranging from less than 1 to 30%. As a result the enzyme-linked immunosorbent assay detected both anti-type-specific and anti-CPS antibodies. After elimination of the anti-CPS, type-specific pneumococcal antibodies were found only occasionally and in low concentrations in serum samples obtained in the acute phase of otitis or before vaccination. The infection induced homologous type-specific pneumococcal antibodies to varying degrees depending on the type: regularly to type 3; and fairly regularly to type 18C polysaccharide, but seldom to type 6 or 19. The pneumococcal vaccine induced type-specific antibodies to all four types measured, but the response to type 6A was poor.
mesh_terms: D000208:Acute Disease; D000907:Antibodies, Bacterial / Q000096:biosynthesis*; D001428:Bacterial Vaccines / Q000276:immunology*; D002648:Child; D002675:Child, Preschool; D004797:Enzyme-Linked Immunosorbent Assay; D006801:Humans; D007070:Immunoglobulin A / Q000096:biosynthesis; D007074:Immunoglobulin G / Q000096:biosynthesis; D007075:Immunoglobulin M / Q000096:biosynthesis; D007136:Immunoglobulins / Q000096:biosynthesis; D007223:Infant; D010033:Otitis Media / Q000276:immunology*; D011008:Pneumococcal Infections / Q000276:immunology*; D022242:Pneumococcal Vaccines; D011135:Polysaccharides, Bacterial / Q000276:immunology*; D013296:Streptococcus pneumoniae / Q000276:immunology*
chemical_list: D000907:Antibodies, Bacterial; D001428:Bacterial Vaccines; D007070:Immunoglobulin A; D007074:Immunoglobulin G; D007075:Immunoglobulin M; D007136:Immunoglobulins; D022242:Pneumococcal Vaccines; D011135:Polysaccharides, Bacterial; C027158:polysaccharide C-substance (Streptococcus)