Cross-protection by POWV mAbs against LGTV challenge in vivo. (A and B) 7-wk-old C57BL/6J mice were administered 250 µg of the indicated mAb and 500 µg of anti-Ifnar1 mAb by intraperitoneal injection 24 h before subcutaneous inoculation with 10² FFU of LGTV. (A) Mice were scored for paralysis following viral infection. (B) Mice were monitored for weight change for 13 d following viral infection. Mean weight change is shown. Error bars represent SEM (ANOVA with Sidak’s post-test: **, P < 0.01; ***, P < 0.001; ****, P < 0.0001). (C–F) At day 14 after viral challenge, serum (C), spleen (D), brain (E), and spinal cord (F) were harvested, and viral load was determined by qRT-PCR. Median viral titers (Kruskal-Wallis ANOVA with Dunn’s post-test: *, P < 0.05; ***, P < 0.001; ****, P < 0.0001). Data are from two experiments. Dotted lines represent the limit of detection of the assay. (G) C57BL/6J mice were administered 250 µg of the indicated mAb by intraperitoneal injection 24 h before subcutaneous inoculation with 10⁴ FFU of TBEV; n = 25 per group (log-rank test with Bonferroni correction: ns, P > 0.0167; *, P < 0.0167; **, P < 0.01). Data are from three experiments.