FIG 5.

Pretreatment with IL-2 Ab Cx reduces the frequency of CHIKV-specific responses in pLN. 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 from draining pLN were isolated at 6 dpi and analyzed using flow cytometry. (A through D) The bar charts show CD45⁺ T cells (A), CD4⁺ T cells (B), CD4⁺ Teff cells (C), and CD4⁺ Tregs (D) per pLN. 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. (E and F) Representative images of ELISpot wells depicting the number of IFN-γ-producing cells in total cells (E) and enriched CD4⁺ T cells (F) from pLN. The bar charts show the average numbers of IFN-γ-producing cells per pLN after subtraction of the background of the IL-2-only stimulation control. 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 < 0.0001 (IL-2 Ab Cx Tregs per pLN), 0.0008 (IL-2 Ab Cx IFN-γ-producing cells per pLN), or 0.0007 (IL-2 Ab Cx IFN-γ-producing CD4⁺ T cells per pLN).