FIG. 8.

Dilution curves from GBS III ELISA in which III-HSA was used at an optimal coating concentration (filled triangles) or at a suboptimal coating concentration (2 orders of magnitude lower than optimal) (open triangles). The relationship between the avidity of the antibodies and their binding to ELISA plates is evident. (Left panel) Reaction of a GBS III vaccine-induced serum of low avidity (avidity index, 12%). (Middle panel) Reaction of a GBS III-TT conjugate vaccine-induced serum pool (SHRS III) of intermediate avidity (avidity index, 35%). (Right panel) Reaction of tetravalent GBS polysaccharide vaccine-induced reference serum 19 of high avidity (avidity index, 71%). Results are means ± SDs for four experiments.