FIG 4.

Pretreatment with IL-2 Ab Cx reduces production of proinflammatory cytokines in joint footpads of CHIKV-infected mice. WT mice (n = 5 per group) were infected s.c. with 10⁶ PFU CHIKV-SGP011 after treatment with PBS, IL-2 only, JES6-1 only, or IL-2 Ab Cx. Cells were stimulated with either IL-2 only or IL-2 plus CHIKV. ELISpot was performed in quadruplicate to detect for CHIKV-specific IFN-γ-producing cells. (A and B) Representative images of ELISpot wells depicting the number of IFN-γ-producing cells in total cells (A) and enriched CD4⁺ T cells (B) from joint footpads. Bar charts show average numbers of IFN-γ-producing cells per infected joint footpad after subtraction of the background of the IL-2-only stimulation control. (C) mRNA was extracted from joint footpads, and qRT-PCR was performed to detect the expression of IL-6, IL-10, ENTPD1, IFN-γ, STAT1, and CXCL10. Statistical analysis was done using one-way ANOVA across all CHIKV-infected groups, followed by Dunnett's posttest comparing to the PBS-CHIKV group. Data are means and SD from three independent experiments. *, P = 0.0127 (IL-2 Ab Cx IL-6) or 0.0113 (IL-2 Ab Cx IL-10); **, P = 0.0037 (IL-2 Ab Cx ENTPD1), 0.0036 (IL-2 Ab Cx IFN-γ), 0.0032 (IL-2 Ab Cx STAT1), or 0.0067 (IL-2 Ab Cx CXCL10); ***, P = 0.0008 (IL-2 Ab Cx IFN-γ-producing cells per joint footpad) or 0.0126 (IL-2 Ab Cx IFN-γ-producing CD4⁺ T cells per joint footpad).