Figure 6.

Inhibition of IgG antibodies (Abs) recognizing SynCP as the coating antigen with OS ligands and CP. Pooled immune sera were obtained after double intraperitoneal immunization of BALB/c mice (n = 6 for each glycoconjugate) with the OS-bovine serum albumin (BSA) conjugates adsorbed on aluminum hydroxide (10 µg of carbohydrate/single dose). The tetra-, hexa-, and octasaccharide ligands, as well as synCP and bacCP, were used as inhibitory materials at concentrations of 0–10 µg/well. The horizontal line indicates the IC₅₀ level at the point of intersection of the inhibition curves. (A) Inhibition of IgG Abs was measured in tetra-BSA conjugate sera at a dilution of 1:400. (B) Inhibition of IgG Abs was measured in hexa-BSA conjugate sera at a dilution of 1:400. (C) Inhibition of IgG Abs was measured in octa-BSA conjugate sera at a dilution of 1:1,600. (D) Inhibition of IgG Abs was measured in Streptococcus pneumoniae type 14 CP-CRM₁₉₇ at a dilution of 1:200. Immune sera were obtained after immunization of mice (n = 6) with Prevenar-13 adsorbed on aluminum phosphate at 2.2 µg (content of S. pneumoniae type 14 CP) per single dose.