Fig. 3

CSF1R antagonism increases mortality and CNS viral burdens during i.c. infection with WNV-NS5-E218A. Mice were fed chow containing PLX5622 or control chow for 2 weeks, infected i.c. with WNV-NS5-E218A at 10⁴ PFU, then monitored for a mortality and b weight loss for up to 25 dpi. a Survival curves show a significant increase in mortality in mice treated with PLX5622 compared with control as calculated by log-rank (Mantel-Cox) test. b Weight was measured daily during acute illness as a measure of illness. After death, the last measured weight was carried through to the end of the experiment. Significantly greater weight loss was measured in PLX5622-treated mice compared with controls as calculated by two-way ANOVA with matched values comparing group means without multiple comparisons. For a and b, data represent the compilation of two independent experiments with 10 mice per group. c At 8 dpi, cortical brain tissue was extracted and relative transcript levels in tissue homogenates were measured by SYBR qRT-PCR for indicated cytokines. Data for individual mice were normalized to Gapdh. Data are presented as mean ± SEM of three to five mice from one experiment. Statistical significance between treatment groups for each cytokine was calculated by t test. d–j Tissue viral loads were measured by plaque assay at 2, 4, 6, and 8 dpi in control (black) or PLX5622-treated (red) mice. k Serum viral loads as measured by qRT-PCR. d–k Data are presented as scatter plots with each mouse represented by a dot with the mean indicated by a line. For d–k, data represent the compilation of two-independent experiments with 10 mice per group. Dotted lines in d–k indicate assay limit of detection. l–o Representative confocal microscopic images of Tunel (red), NeuN (green), and DAPI (blue) of hippocampus (l, m) and cerebellum (n, o) of control- (l, n) or PLX5622-treated (m, o) mice infected i.c. with WNV-NS5-E218A at 6 dpi. Arrow heads point to DAPI-positive nuclei positive for both Tunel and NeuN. Asterisks denote DAPI- and Tunel-positive but NeuN-negative nuclei. p Quantification of confocal microscopic images for number of DAPI-positive nuclei positive for Tunel and NeuN in the hippocampus (Hpc), cerebellum (Cb), and brainstem (Bs). The number of Tunel+ NeuN+ nuclei per high-power field (HPF) was quantified from three to six images captured at × 40 per brain region across two separate brain sections for each of five independent mice collected in one experiment. Each symbol represents the average number for an individual mouse, with bar indicating mean ± SEM. Statistical significance was calculated using two-way ANOVA with Sidak’s multiple comparisons test. For all data: ns, not significant at P < 0.05; *P < 0.05; **P < 0.01; ****P < 0.0001