Lentivirus degradation and DC-SIGN expression by human platelets and megakaryocytes.
OBJECTIVE
As platelets are able to endocytose human immunodeficiency virus (HIV), we have investigated the fate of lentiviruses when endocytosed by human platelets and megakaryocytes (MK), and have characterized a specific receptor directly involved in this function.


METHODS
Genetically modified (non-replicative) lentiviruses with an HIV envelope (HIV-e) or with a vesicular stomatitis virus protein G envelope (VSV-e) were alternatively used and their interaction with platelets and MK analyzed by electron microscopy (EM) and immunoEM.


RESULTS
When incubated with platelets, HIV-e and VSV-e lentiviruses were internalized in specific endocytic vesicles and trafficked to the surface connected canalicular system (SCCS). Double immunolabeling for the viral P24 core protein and alpha-granule markers showed that lentiviruses were degraded in the SCCS after contact with alpha-granule proteins. In culture MK, lentiviruses were found in endocytic vesicles and accumulated in acid phosphatase-containing multivesicular bodies (MVB). The expression of the pathogen receptor dendritic cell-specific ICAM-grabbing non-integrin (DC-SIGN) was then demonstrated in platelets by flow cytometry, immunoEM and Western blot. Anti-DC-SIGN antibodies decreased HIV-e lentivirus internalization by platelets, showing that the receptor is functional. Specific signals for DC-SIGN protein and mRNA were also found in MK.


CONCLUSIONS
This study indicates that platelets and MK can internalize lentiviruses in a pathway, which either provide a shelter to lentiviral particles or alternatively disrupts viral integrity. The receptor DC-SIGN is involved in this function.
Boukour
S
S
Département d'Hématologie, Institut Cochin, INSERM U567, Paris and Faculté de médecine, Paris-Ile de France-Ouest, France.
Massé
J-M
JM
Bénit
L
L
Dubart-Kupperschmitt
A
A
Cramer
E M
EM
D000911:Antibodies, Monoclonal; D001483:Base Sequence; D001792:Blood Platelets / Q000378:metabolism* / Q000648:ultrastructure / Q000821:virology*; D015815:Cell Adhesion Molecules / Q000037:antagonists & inhibitors / Q000097:blood* / Q000235:genetics / Q000276:immunology; D018076:DNA, Complementary / Q000235:genetics; D004705:Endocytosis; D015870:Gene Expression; D015752:Genes, env; D005822:Genetic Vectors; D015497:HIV-1 / Q000235:genetics; D006367:HeLa Cells; D006801:Humans; D066298:In Vitro Techniques; D037181:Lectins, C-Type / Q000037:antagonists & inhibitors / Q000097:blood* / Q000235:genetics / Q000276:immunology; D016086:Lentivirus / Q000235:genetics / Q000472:pathogenicity*; D008533:Megakaryocytes / Q000378:metabolism* / Q000648:ultrastructure / Q000821:virology*; D008854:Microscopy, Electron; D012333:RNA, Messenger / Q000097:blood / Q000235:genetics; D011956:Receptors, Cell Surface / Q000037:antagonists & inhibitors / Q000097:blood* / Q000235:genetics / Q000276:immunology; D011991:Receptors, Virus / Q000097:blood / Q000235:genetics; D014721:Vesicular stomatitis Indiana virus / Q000235:genetics; D000099215:DC-Specific ICAM-3 Grabbing Nonintegrin
D000911:Antibodies, Monoclonal; D015815:Cell Adhesion Molecules; D018076:DNA, Complementary; D037181:Lectins, C-Type; D012333:RNA, Messenger; D011956:Receptors, Cell Surface; D011991:Receptors, Virus; D000099215:DC-Specific ICAM-3 Grabbing Nonintegrin