S100B and HIV-1 infection: In this review, we will summarize the current understanding of various human DC subsets based on several outstanding recent findings in DC biology and of antiviral immune responses initiated by DCs, and discuss about newly identified DC restriction factors counteracting HIV-1 accessory proteins (e.g., Vif, Vpu, and Nef), which may have an impact on (1) the susceptibility of DC to HIV-1 infection and (2) the transmissibility of HIV from DC to T cells via VS or IS.