TLR2 and HIV-1 infection: Immature Langerhans' cells protect against HIV-1 infection by internalizing and degrading HIV-1 viral particles and inhibiting T-cell infection [13], but Langerhans' cells activated through exposure to microbial-associated inflammatory molecules such as lipopolysaccharide (LPS), TNF-α, and Toll-like receptor 2 (TLR2) agonists are efficient mediators of HIV-1 trans-infection [14]–[16].