title: A clathrin-dynamin-dependent endocytic pathway for the uptake of HIV-1 by direct T cell-T cell transmission.
abstract: Cellular contacts between HIV-1-infected cells and target primary T CD4+ lymphocytes trigger the formation of a structure known as the virological synapse. As a consequence, viral production in HIV-1-infected cells is polarized towards the virological synapse and nascent viral particles are directly transferred to target T CD4+ lymphocytes. In this study, we performed short time cocultures of target primary T CD4+ lymphocytes with effector T cells infected by either HIV-1 NL4-3 or BaL. Using flow cytometry and immuno-confocal analyses, we investigated the transfer of HIV-1 virion antigens. We found that after 3 h of coculture, unstimulated T CD4+ lymphocytes captured complete HIV-1 virions from infected T cells during cell-cell contacts. Virus transfer occurred through a dynamin-dependent pathway and could be inhibited by chlorpromazine, an inhibitor of clathrin-dependent endocytosis. Transferred HIV-1 virions were located in compartments close to the surface of the target cell in a polarized manner. These compartments were positive for clathrin and the early endosomal marker EEA1 but were negative for caveolin-1. Furthermore, the great majority of internalized HIV-1 particles did not colocalize with Lamp1, a well-known marker for the lysosomal-degradative pathway. Similar results were observed when stimulated primary T CD4+ lymphocytes were the target cells. Our results suggest a mechanism of cell to cell HIV-1 transfer through a clathrin- and dynamin-dependent early endocytic pathway where internalized HIV-1 particles would not reach Lamp1 positive compartments, suggesting that during HIV-1 transfer by cell-cell contacts, virions can be taken up by endocytosis but not be degraded in lysosomes.
authors.affiliation: Retrovirology Laboratory IrsiCaixa, Hospital Universitari Germans Trias i Pujol, Universitat Autònoma de Barcelona, Badalona, Spain.
authors.forename: Berta
authors.initials: B
authors.lastname: Bosch
authors.forename: Boyan
authors.initials: B
authors.lastname: Grigorov
authors.forename: Jordi
authors.initials: J
authors.lastname: Senserrich
authors.forename: Bonaventura
authors.initials: B
authors.lastname: Clotet
authors.forename: Jean-Luc
authors.initials: JL
authors.lastname: Darlix
authors.forename: Delphine
authors.initials: D
authors.lastname: Muriaux
authors.forename: José A
authors.initials: JA
authors.lastname: Este
mesh_terms: D015496:CD4-Positive T-Lymphocytes / Q000378:metabolism / Q000821:virology*; D002478:Cells, Cultured; D002746:Chlorpromazine / Q000494:pharmacology; D002966:Clathrin / Q000378:metabolism*; D018920:Coculture Techniques; D034281:Dynamins / Q000378:metabolism*; D004705:Endocytosis / Q000187:drug effects; D015658:HIV Infections / Q000378:metabolism / Q000503:physiopathology / Q000635:transmission*; D015497:HIV-1 / Q000502:physiology*; D006801:Humans; D051907:Lysosomal Membrane Proteins / Q000378:metabolism; D053586:Virus Internalization / Q000187:drug effects; D052118:Lysosomal-Associated Membrane Protein 1
chemical_list: D002746:Chlorpromazine; D002966:Clathrin; D034281:Dynamins; D051907:Lysosomal Membrane Proteins; C489116:LAMP1 protein, human; D052118:Lysosomal-Associated Membrane Protein 1