Dendritic cells and HIV-specific CD4+ T cells: HIV antigen presentation, T-cell activation, and viral transfer.

Arnaud Moris (1) , Anthony Pajot (1) , Fabien Blanchet (1) , Florence Guivel-Benhassine (1) , Margarita Salcedo (1) , Olivier Schwartz (1)

1 Virus et Immunité

Human immunodeficiency virus (HIV)-specific CD4+ lymphocytes are preferentially infected in HIV-positive individuals. To study this preferential infection, we have derived several HIV-specific (HS) CD4+ clones. We show that in dendritic cells (DCs), HIV virion capture led to major histocompatibility complex class-II (MHC-II)-restricted viral antigen presentation and to activation of HS cells. In contrast, neither cell-free virions nor infected lymphocytes activated HS cells. In DCs, the dendritic cell-specific intercellular adhesion molecule 3-grabbing nonintegrin (DC-SIGN/CD209), which internalizes virions, promoted MHC-II presentation of HIV antigens. Activation of HS cells by HIV-exposed DCs triggered an efficient viral spread in lymphocytes. CD4+ clones with irrelevant antigenic specificities were not activated by HIV-exposed DCs and poorly supported viral replication under this setting. Our results unravel the mechanisms of MHC-II-restricted HIV antigen presentation by DCs and describe how HIV gains access to the very cells designed by the immune system to counteract this pathogen.

Domains: Life Sciences [q-bio]

Arnaud Moris, Anthony Pajot, Fabien Blanchet, Florence Guivel-Benhassine, Margarita Salcedo, et al.. Dendritic cells and HIV-specific CD4+ T cells: HIV antigen presentation, T-cell activation, and viral transfer.. Blood, 2006, 108 (5), pp.1643-51. ⟨10.1182/blood-2006-02-006361⟩. ⟨pasteur-01372632⟩