Figure 5.

Inhibition of IgG1 antibodies (Abs) in mice immune sera with OS ligands and CP. Enzyme-linked immunosorbent assay inhibition assays were performed using streptavidin-coated plates with tetra-biotin, hexa-biotin, and octa-biotin adsorbed on their surfaces. (A–C) Inhibition of IgG1 Abs in the pooled sera of BALB/c mice (n = 6) that were immunized twice intraperitoneally with glycoconjugates at 10 µg/dose. Sera were obtained 14 days after the second immunization. Serum samples for all glycoconjugates were diluted 1:4,000. The tetra-, hexa-, and octasaccharide ligands, synCP, and bacCP were used as inhibitors and applied in amounts ranging from 0 to 10 µg/well. The horizontal line indicates the IC₅₀ at the point of intersection of the inhibition curves. (A) Tetra-bovine serum albumin (BSA) conjugate antiserum was tested against tetra-biotin capture material. (B) Hexa-BSA conjugate antiserum was tested against hexa-biotin capture material (C). Octa-BSA conjugate antiserum was tested against octa-biotin capture material. (D) Inhibition of IgG1 Abs was measured in the pooled sera of BALB/c mice immunized twice intraperitoneally over 2 weeks with the conjugated pneumococcal vaccine, Prevenar-13, at 1.1 µg of Streptococcus pneumoniae type 14 CP per single dose. The dilutions of sera tested against the tetra-biotin and octa-biotin coating antigens were 1:500; hexa-biotin was diluted 1:300. (E) Inhibition of IgG Abs was measured in serum harvested from rabbits that were immunized multiple times with inactivated S. pneumonia type 14 bacteria. The dilution of rabbit sera tested against tetra-biotin coating antigens was 1:300, against hexa-biotin and octa-biotin coating antigens was 1:3,000; n = 3 per data point.