CD4 and HIV-1 infection: Antibodies that bind CD4 and CCR5 partially block the uptake of R5-tropic HIV-1 by LCs (Hladik et al., 2007). LC serves detecting HIV-1 entry into the vagina, through C-type lectin receptor (CLR), Toll-like receptor (TLR) and other recognition receptors (Chang & Altfeld, 2009). The entry by the assistance of Langerhans cell solely depends on the activation status of the LC. As immature LCs prevent HIV-1 infection by clearing invading HIV-1 through the C-type lectin langerin but blocking langerin function by high virus concentrations enables HIV-1 transmission by LCs (Nishibu et al., 2006).