Figure 6. SINV/EEEV egress inhibiting mAbs, EEEV-109 (‘EEEV-specific’) and EEEV-179 (‘New World’), treat EEEV-induced disease.
A to H. C57BL/6 mice (5 to 7-weeks old) were inoculated subcutaneously (s.c.) with 103.3 CCID50 of EEEV (strain FL93–939) 24 hours prior to mAb administration intraperitoneally (i.p.) at 20 or 200 μg/mouse (1 mg/kg or 10 mg/kg, respectively; n=10). A mock control was included (n=5; grey). A. EEEV-109 (hybridoma-derived) or rEEEV-109 IgG1 (10 mg/kg; green), rEEEV-109 IgG1 (1 mg/kg; light green), rEEEV-109 LALA-PG (10 mg/kg; blue), or rEEEV-109 LALA-PG (1 mg/kg; light blue) mediated 100, 40, 90, or 60%, respectively, therapeutic survival compared to the negative control mAb rDENV-2D22 (10 mg/kg; black). Survival curves were compared using the log-rank test with Bonferroni multiple comparison correction (**padj<0.01, ***padj<0.001). B and F. Percent body weight change of mAb or mock-treated C57BL/6 mice over the course of 18 days after EEEV inoculation. C and G. Virus titer (log10CCID50/mL; y-axis) in serum collected 3 days post-inoculation was determined by an infectious cell culture assay. mAb or mock-treated controls are indicated on the x-axis. Virus titer in the serum for the treatment groups were compared to rDENV-2D22 using an ordinary one-way ANOVA with Dunnett’s multiple comparisons test (*p<0.05, **p<0.01). D and H. Disease signs (limb weakness [yellow], hunching [light orange], lethargy [orange], paralysis [red], and moribund [dark red]) of mAb or mock-treated C57BL/6 mice over the course of 21 days after EEEV inoculation. E. rEEEV-179 IgG1 (10 mg/kg; magenta), EEEV-138 (10 mg/kg; pink), or rEEEV-346 IgG1 (10 mg/kg; purple) mediated 80, 40, or 30%, respectively, therapeutic survival compared to rDENV-2D22 (10 mg/kg; black). Survival curves were compared using the log-rank test with Bonferroni multiple comparison correction (*padj<0.05). I to M. C57BL/6 mice (4-weeks-old) were administered 200 μg/mouse (10 mg/kg; n=7) of rEEEV-346 IgG1 (purple) or the West Nile virus-specific negative control human mAb hE16 (black), via the i.p. route 24 hours prior to s.c. footpad inoculation with 103 FFU of CHIKV strain LR 2006 OPY1. I. rEEEV-346 IgG1 reduced joint swelling at 2 and 6 dpi. Joint swelling in the rEEEV-346 IgG1 treatment group was compared to hE16 using a two-way ANOVA with Dunnett’s multiple comparisons test (***p<0.001, ****p<0.0001). J to M. Viral RNA levels were assessed in the ipsilateral or contralateral ankles (J and L) and muscles (K and M) 6 dpi. Viral RNA levels present within the ipsilateral or contralateral ankles or muscles of the rEEEV-346 IgG1 treatment group were compared to hE16 using a one-way ANOVA with Dunnett’s multiple comparisons test (**p<0.01, ***p<0.001).