FIG 3.

Pretreatment with IL-2 Ab Cx abrogates CD4⁺ infiltration into the 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. Joint footpad cells from these treated animals were isolated at 6 dpi, enriched by Percoll, and analyzed by flow cytometry. Cells were stained with Live/Dead aqua and with antibodies to CD3, CD4, CD11b, Ly6C, and Ly6G. (A) Representative scatter plots showing CD45 and CD4 expression, gated on live cells. Numbers in scatter plots indicate CD4⁺ population percentages of total live cells. Bar charts show average numbers of total leukocytes (left) and CD4⁺ T cell infiltrates (right). (B) Representative scatter plots showing CD11b and Ly6G expression gated on live CD45⁺ cells. Numbers in scatter plots indicate the percentages of cells in respective quadrants of total live CD45⁺ cells. Bar charts show average numbers of total myeloid cells (left) and neutrophil infiltrates (right). (C) Representative scatter plots showing CD11b and Ly6C expression gated on live CD45⁺ cells. Numbers in scatter plots indicate the percentages of cells in respective quadrants of total live CD45⁺ cells. Bar charts show average number of Ly6C⁻ macrophage (left) and Ly6C⁺ macrophage (right) infiltrates. All data are means and SD from 3 independent experiments. Statistical analysis was performed using one-way ANOVA across all CHIKV-infected groups, followed by Dunnett's posttest comparing to the PBS-CHIKV group. ***, P < 0.0001 (IL-2 Ab Cx CD4⁺ T cells).