However, in the context of co-infection with other sexually transmitted organisms, such as the bacterium Neisseria gonorrhoeae and/or the fungus Candida albacans [41] or when stressed by skin abrasion [42], Langerhans cells can become more susceptible to HIV-1 infection and are able to transmit HIV-1 to CD4+ T cells effectively [42]. Here, CD4 is linked to HIV-1 infection.