title: Human immunodeficiency virus type 1 (HIV-1) protease inhibitors block cell-to-cell HIV-1 endocytosis in dendritic cells.
abstract: Sexual transmission is now the most frequent means of diffusion of human immunodeficiency virus type 1 (HIV-1). Even if the underlying mechanism is still largely unknown, there is a consensus regarding the key role played by mucosal dendritic cells (DCs) in capturing HIV through contact with infected subepithelial lymphocytes, and their capacity to spread HIV by trans-infection. We found that HIV protease inhibitors (PIs) reduced virion endocytosis strongly in monocyte-derived immature (i) DCs contacting HIV-1-infected cells, and that this phenomenon led to dramatically impaired trans-infection activity. This inhibitory effect was not mediated by the block of viral protease activity, as it was also operative when donor cells were infected with a PI-resistant HIV-1 strain. The block of virus maturation imposed by PIs did not correlate with significant variations in the levels of virus expression in donor cells or of Gag/Env virion incorporation. Also, PIs did not affect the endocytosis activity of DCs. In contrast, we noticed that PI treatment inhibited the formation of cell-cell conjugates whilst reducing the expression of ICAM-1 in target iDCs. Our results contribute to a better delineation of the mechanisms underlying HIV-1 trans-infection activity in DCs, whilst having implications for the development of new anti-HIV microbicide strategies.
authors.affiliation: Division of Pathogenesis of Retroviruses, National AIDS Center, Istituto Superiore di Sanità, Rome, Italy.
authors.forename: Claudia
authors.initials: C
authors.lastname: Muratori
authors.affiliation: Division of Pathogenesis of Retroviruses, National AIDS Center, Istituto Superiore di Sanità, Rome, Italy.
authors.forename: Eliana
authors.initials: E
authors.lastname: Ruggiero
authors.affiliation: Division of Pathogenesis of Retroviruses, National AIDS Center, Istituto Superiore di Sanità, Rome, Italy.
authors.forename: Antonella
authors.initials: A
authors.lastname: Sistigu
authors.affiliation: Division of Pathogenesis of Retroviruses, National AIDS Center, Istituto Superiore di Sanità, Rome, Italy.
authors.forename: Roberta
authors.initials: R
authors.lastname: Bona
authors.affiliation: Division of Pathogenesis of Retroviruses, National AIDS Center, Istituto Superiore di Sanità, Rome, Italy.
authors.forename: Maurizio
authors.initials: M
authors.lastname: Federico
mesh_terms: D000818:Animals; D002448:Cell Adhesion / Q000187:drug effects*; D002460:Cell Line; D002478:Cells, Cultured; D018920:Coculture Techniques; D003713:Dendritic Cells / Q000502:physiology / Q000821:virology*; D004705:Endocytosis; D017320:HIV Protease Inhibitors / Q000494:pharmacology*; D015497:HIV-1 / Q000187:drug effects*; D006801:Humans; D018799:Intercellular Adhesion Molecule-1 / Q000096:biosynthesis
chemical_list: D017320:HIV Protease Inhibitors; D018799:Intercellular Adhesion Molecule-1