HIV‐1 Trafficking to the Dendritic Cell–T‐Cell Infectious Synapse Uses a Pathway of Tetraspanin Sorting to the Immunological Synapse

• Published in: Traffic (Copenhagen, Denmark) Denmark), 2005-06, Vol.6 (6), p.488-501
• Main Authors: Garcia, Eduardo, Pion, Marjorie, Pelchen‐Matthews, Annegret, Collinson, Lucy, Arrighi, Jean‐Francois, Blot, Guillaume, Leuba, Florence, Escola, Jean‐Michel, Demaurex, Nicolas, Marsh, Mark, Piguet, Vincent
• Format: Article
• Language: English
• Subjects: Antigens, CD - biosynthesis; CD4 antigen; CD4-Positive T-Lymphocytes - immunology; CD63 antigen; CD81 antigen; CD9 antigen; Cell Separation; Cell-Free System; Cells, Cultured; Dendritic cells; Dendritic Cells - virology; Electron microscopy; Endocytosis; endosomes; Endosomes - metabolism; Flow Cytometry; HIV; HIV-1 - metabolism; Human immunodeficiency virus 1; Humans; Hydrogen-Ion Concentration; imaging; Immunofluorescence; Immunological synapses; Infection; infectious synapse; Infectivity; Kangai-1 Protein; LAMP-1 protein; Lymphocytes T; Lysosomal Membrane Proteins; Lysosomes - metabolism; Major histocompatibility complex; Membrane Glycoproteins - biosynthesis; Membrane Proteins - metabolism; Microscopy, Electron; Microscopy, Fluorescence; Monocytes - cytology; pH effects; Platelet Membrane Glycoproteins - biosynthesis; Proto-Oncogene Proteins - biosynthesis; T-cell receptor; T-Lymphocytes - virology; Temperature; Tetraspanin 28; Tetraspanin 29; Tetraspanin 30; Time Factors; trans infection; Vacuoles; Virions
• ISSN: 1398-9219; 1600-0854
• DOI: 10.1111/j.1600-0854.2005.00293.x

Dendritic cells (DCs) are essential components of the early events of HIV infection. Here, we characterized the trafficking pathways that HIV‐1 follows during its capture by DCs and its subsequent presentation to CD4+ T cells via an infectious synapse. Immunofluorescence microscopy indicates that the virus‐containing compartment in mature DCs (mDCs) co‐labels for the tetraspanins CD81, CD82, and CD9 but contains little CD63 or LAMP‐1. Using ratio imaging of pH‐reporting fluorescent virions in live DCs, we show that HIV‐1 is internalized in an intracellular endocytic compartment with a pH of 6.2. Significantly, we demonstrate that the infectivity of cell‐free virus is more stable at mildly acidic pH than at neutral pH. Using electron microscopy, we confirm that HIV‐1 accumulates in intracellular vacuoles that contain CD81 positive internal membranes but overlaps only partially with CD63. When allowed to contact T cells, HIV‐1‐loaded DCs redistribute CD81, and CD9, as well as internalized HIV‐1, but not the immunological synapse markers MHC‐II and T‐cell receptor to the infectious synapse. Together, our results indicate that HIV‐1 is internalized into a non‐conventional, non‐lysosomal, endocytic compartment in mDCs and further suggest that HIV‐1 is able to selectively subvert components of the intracellular trafficking machinery required for formation of the DC–T‐cell immunological synapse to facilitate its own cell‐to‐cell transfer and propagation.