Pneumococcal antibodies of different immunoglobulin subclasses in normal and IgG subclass deficient individuals of various ages.

The distribution of pneumococcal antibody activity of the IgG and IgA subclasses was determined in healthy individuals of various ages using monoclonal antibodies in an enzyme linked immunosorbent assay (ELISA). High IgG 2 antibody activity was found in cord blood and in serum from adults. IgG 1 activity was most pronounced in serum from young children and virtually lacking in serum from adults. Anti-pneumococcal antibodies were found to be low in IgG 2 deficient donors and normal in IgG 3 deficient donors. A maturation from relatively low IgG 1 and IgG 2 antipneumococcal activity in young children to high IgG 2 levels in adults was found in healthy individuals. IgA subclass antipneumococcal activity was correlated to age. Evaluation of the distribution of pneumococcal antibody activity of various subclasses offers a new possibility for studying the immune response to infection and immunization.