Vaginal epidermal dendritic cells: defense against HIV-1 or a safe haven?

Langerhans cells (LCs) are likely among the first targets of HIV-1 infection due to their localization in mucosal tissues. In their recent work, Pena-Cruz and colleagues were able to study HIV-1 infection in vaginal epithelial DCs (VEDCs), termed CD1a+ VEDCs. They show that VEDCs are distinct from other blood- and tissue-derived DCs or LCs because they express the protein langerin but not the lectin receptor DC-SIGN, and they do not have Birbeck granules. The results from this study indicate that HIV-1 using CXCR4 replicates poorly in VEDCs but that a higher replication for HIV-1 using CCR5 strains is supported by VDECs. Furthermore, Pena-Cruz and colleagues demonstrate that VDECs can represent a viral reservoir in HIV-1-infected virologically suppressed women. As such, VDECs may represent another sanctuary of viral persistence and can be an additional obstacle to viral eradication.