Figure 5.

Avidity index (AI) of YFE-specific NHP IgG after vaccination with YFE-1, YFE-2E, and YF 17DD. Groups of NHPs were immunized as indicated in the “Materials and Methods” section. Box plot graphs represent distribution of AI (%) for total anti-YFE IgG in serum from monkeys immunized with YFE-1 (A) YFE-2E, (B) YF 17DD, (C) and at different days postvaccination (d.p.v.). Error bars show outliers and horizontal bars represent means. Sera with AI lower than 49% are considered low avidity. Sera with AIs ranging from 50% to 75% are considered medium avidity and sera with AIs higher than 75% are considered high avidity. The means were compared using analysis of variance-Tukey post-hoc test. *P < 0.05, **P < 0.01, ***P < 0.001. IgG = immunoglobulin G; NHP = nonhuman primates; YFE = yellow fever virus envelope protein.