These results suggest that CCR5 ablation results in a skewed IL-17+CD4+ Th17 response in both extraneural lymphoid tissue and the CNS, which leads to reduced CNS infiltration of CD4+Foxp3+ Tregs during JE progression, which is closely associated with exacerbation of JE in Ccr5−/− mice. Here, CD4 is linked to Japanese encephalitis.