HIV-1 trafficking to the dendritic cell-T-cell infectious synapse uses a pathway of tetraspanin sorting to the immunological synapse.
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.
Garcia
Eduardo
E
Department of Dermatology and Venereology, University Hospital of Geneva, Geneva, Switzerland.
Pion
Marjorie
M
Pelchen-Matthews
Annegret
A
Collinson
Lucy
L
Arrighi
Jean-Francois
JF
Blot
Guillaume
G
Leuba
Florence
F
Escola
Jean-Michel
JM
Demaurex
Nicolas
N
Marsh
Mark
M
Piguet
Vincent
V
D015703:Antigens, CD / Q000096:biosynthesis; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology; D002469:Cell Separation; D002474:Cell-Free System; D002478:Cells, Cultured; D003713:Dendritic Cells / Q000821:virology*; D004705:Endocytosis; D011992:Endosomes / Q000378:metabolism; D005434:Flow Cytometry; D015497:HIV-1 / Q000378:metabolism*; D006801:Humans; D006863:Hydrogen-Ion Concentration; D051861:Kangai-1 Protein; D051907:Lysosomal Membrane Proteins; D008247:Lysosomes / Q000378:metabolism; D008562:Membrane Glycoproteins / Q000096:biosynthesis; D008565:Membrane Proteins / Q000378:metabolism*; D008854:Microscopy, Electron; D008856:Microscopy, Fluorescence; D009000:Monocytes / Q000166:cytology; D010980:Platelet Membrane Glycoproteins / Q000096:biosynthesis; D011518:Proto-Oncogene Proteins / Q000096:biosynthesis; D013601:T-Lymphocytes / Q000821:virology*; D013696:Temperature; D060225:Tetraspanin 28; D060245:Tetraspanin 29; D060149:Tetraspanin 30; D013997:Time Factors
D015703:Antigens, CD; C554586:CD63 protein, human; C554798:CD81 protein, human; C497688:CD82 protein, human; C554869:CD9 protein, human; D051861:Kangai-1 Protein; D051907:Lysosomal Membrane Proteins; D008562:Membrane Glycoproteins; D008565:Membrane Proteins; D010980:Platelet Membrane Glycoproteins; D011518:Proto-Oncogene Proteins; D060225:Tetraspanin 28; D060245:Tetraspanin 29; D060149:Tetraspanin 30