Figure EV5. CD4-depletion reduces CHIKV disease severity.

(A) Wild-type animals were infected with 1 × 10⁶ PFU of CHIKV in the right footpad and anti-CD4 antibodies were given intraperitoneally at -1 and 4 days post-infection (dpi). Immunophenotyping of joint-footpad was performed at 6 dpi to determine the numbers of infiltrating CD4⁺ T cells. Data were from biological replicates obtained from two independent experiments and presented as mean ± SD. Data comparisons between the groups were performed with non-parametric Mann–Whitney U test (two-tailed). CD4⁺ T cells, ***P = 0.000000449. (B,C) Joint-footpad swelling (B) and viral RNA load (C) of CHIKV-infected animals with or without administration of anti-CD4 antibodies, over a period of 14 days. Data were from biological replicates obtained from two independent experiments and presented as mean ± SD. Data comparisons between the groups were performed with non-parametric Mann–Whitney U test (two-tailed). For footpad swelling: 5 dpi, *P = 0.0192; 6 dpi, **P = 0.0012; 7 dpi, **P = 0.0012; 8 dpi, **P = 0.0012; 9 dpi, **P = 0.0012; 10 dpi, **P = 0.0023. (D) Numbers of infiltrating CD45⁺ cells, neutrophils, B cells, NKT cells. NK cells, LFA-1⁺CD4⁺ T cells, CD8⁺ T cells, LFA-1⁺CD4⁺ T cells, CD11b⁺Ly6C⁺ cells and CD64⁺MHCII^- cells were determined following immunophenotyping of the joint-footpad at 6 dpi (A). Data were from biological replicates obtained from two independent experiments and presented as mean ± SD. Data comparisons between the groups were performed with non-parametric Mann–Whitney U test (two-tailed). CD45⁺, **P = 0.0042; NKT, ***P = 0.0000306; NK, **P = 0.0075; LFA-1⁺CD4⁺ T, ***P = 0.000000449; CD8⁺, *P = 0.0108; LFA-1⁺CD8⁺ T, *P = 0.0179.