Fig. 1. PS-IMPs ameliorate WNV encephalitis in mice.

(A) Survival of WNV-infected mice treated with PS-IMPs, PS-NPs (neutral particle control), or vehicle control. Surviving mice were rechallenged with lethal 3 × 10⁸ plaque-forming units (PFU) of WNV on day 60 (gray arrow). (B) Numbers of ΦIM-derived macrophages (SSC^lo/FSC^lo/CD45^hi/CD11b⁺/Ly6C^+/hi) in the brains of PS-IMP, PS-NP, or vehicle control–treated mock or WNV-infected mice 24 hours after therapy (day 7 after infection). (C) Survival of WNV-infected mice treated with PLGA-IMP, PS-NP, ND-IMP, or vehicle. (D) Survival of WNV-infected mice treated with PS-IMP, opsonized PS-IMP, or vehicle control. (E) Numbers of ΦIM-derived macrophages in the brains of PS-IMP, PS-NP, PS-PP (positively charged particles), or vehicle control–treated or WNV-infected mice 24 hours after therapy (day 7 after infection). (F) Survival of WNV-infected mice treated with PS-IMP, PS-NP, PS-PP, or vehicle control. (G and H) Survival of WNV-infected mice treated with increasing doses of PS-IMP or vehicle control (G) per dose (mg) or (H) as particle number. Survival data represent three separate experiments with 10 to 20 mice per group. Statistical analysis was conducted with the Mantel-Haenszel log-rank test. Flow cytometry data are means ± SD and represent three separate experiments with four to five mice per group. Statistical analysis was conducted with one-way analysis of variance (ANOVA) and Tukey-Kramer post-test. *P ≤ 0.05, **P ≤ 0.01, ***P ≤ 0.001, comparing PS-IMP and NP groups to vehicle control groups; ^#P ≤ 0.05, ^##P ≤ 0.01, ^###P ≤ 0.001, comparing PS-IMP to NP groups.