ASSIGNMENT OF IMMUNOGLOBULIN G1 AND G2 CONCENTRATIONS TO PNEUMOCOCCALCAPSULAR POLYSACCHARIDE-3, POLYSACCHARIDE-6B, POLYSACCHARIDE-14, POLYSACCHARIDE-19F, AND POLYSACCHARIDE-23F IN PNEUMOCOCCAL REFERENCE SERUM89-SF

We describe standardization of an enzyme-linked immunosorbent assay (E LISA) for measuring immunoglobulin G1 (IgG1) and IgG2 concentrations o f antibodies to pneumococcal capsular polysaccharide (Pnc PS), The ELI SA uses a human pneumococcal reference serum pool, lot 89-SF, as a ref erence. IgG1 and IgG2 concentrations were assigned to antibodies to Pn c PS serotypes 3, 6B, 14, 19F, and 23F in 89-SF by ELISA using affinit y-purified monoisotypic IgG1 and IgG2 preparations. The sum of IgG1 an d IgG2 concentrations in 89-SF agrees well with the previously assigne d IgG concentrations. The IgG1 and IgG2 values in 89-SF were used to m easure antibodies to Pnc PS 6B, 14, and 23F in adult pre- and postimmu nization sera and the sum of IgG1 and IgG2 concentrations correlated w ell with the IgG values. Furthermore, the IgG2/IgG1 ratio did not affe ct the detection of IgG1, the isotype usually represented by a lower c oncentration.