CCL4 and HIV-1 infection: While CCR5 mediates HIV-1 infection of macrophages and microglia, similar to CCR5 antagonists (e.g., maraviroc), CCR5 ligands (e.g., CCL4 and CCL5) can also act as inhibitors of CCR5-preferring viruses and thus reduce CCR5-mediated HIV-1 infection (Maung et al., 2014; Ojeda-Juárez et al., 2020; Tyner et al., 2005).