CCL4 and infection: CCL4 was expressed at significantly higher levels in livers of WSX-1−/− mice compared to WT mice on day 7 of infection (Fig. 2A), whereas CCL4 and CCL5, both ligands for CCR5, were expressed at 5–10-fold higher levels in livers of WSX-1−/− mice compared to WT mice on day 14 of infection (Fig. 2B).