FIG 7.

ZIKV infection triggers protective immunity against secondary homologous infection. (A) Neutralizing antibody kinetics in ZIKV-infected animals. Dotted lines represent the limits of detection. (B) Passive transfer protection experiments were performed in 1-day-old suckling BALB/c mice using antisera and 10-fold dilutions (n = 5) of antisera from ZIKV-infected tree shrews (n = 5). PBS was included as the mock control (n = 5). The Kaplan-Meier survival curves were analyzed by the log-rank test. *** denotes a P value of less than 0.01. (C and D) All tree shrews that received 10⁵ or 10⁶ PFU of ZIKV were rechallenged with the same dose of ZIKV at 21 days post primary infection. Viremia was monitored for 7 days after each challenge. The limit of detection is indicated by the dotted line.