Age-dependent IgG subclass distribution of phosphocholine antibodies in humans

Plasma antiphosphoryl-choline (Pc) antibodies were analyzed regarding class and subclass distribution (IgG, IgG1-4, IgM and IgA). Plasma was collected from healthy and otitis-prone children, 1 and 3 years of age, and healthy adults. An enzyme-linked immunosorbent assay (ELISA) was used, utilizing monoclonal antibodies to human IgG subclass determinants. Divergent patterns emerged when comparing children with adults. At 1 year of age the anti-PC IgG1 levels were higher in both of the two children groups than in adults, while the reverse pattern was seen for IgG2 antibodies. There was no correlation between total plasma levels of IgG1-4 immunoglobulins and the ELISA value of specific antibody. The age-dependent subclass patterns corresponded to the earlier descriptions of antibodies to certain pneumococcus polysaccharides. Anti-Pc antibody levels were unrelated to predisposition to otitis media.