Cell-to-cell fusion, but not virus entry in macrophages by T-cell line tropic HIV-1 strains: a V3 loop-determined restriction.
T-cell lines chronically infected with laboratory adapted, T-cell tropic HIV-1 strains (RF, LAI, CBL-4, and NY5) induced syncytia after cocultivation with primary macrophages. Such fusion-competent strains, however, replicated inefficiently after cell-free infection of macrophage cultures. Evidence based on proviral DNA synthesis, pseudotype penetration, and a V3 loop mutation revealed that cell-free infection was restricted at a prepenetration stage in entry and controlled by envelope sequences. Our results suggest that primary macrophages are sensitive to cell-to-cell but not to virion-to-cell fusion induced by the envelope glycoproteins of several T-cell tropic HIV-1 strains.
Simmons
G
G
Virology Laboratory, Chester Beatty Laboratories, Institute of Cancer Research, London.
McKnight
A
A
Takeuchi
Y
Y
Hoshino
H
H
Clapham
P R
PR
D002450:Cell Communication; D002459:Cell Fusion; D002460:Cell Line; D002474:Cell-Free System; D015686:Gene Products, env / Q000737:chemistry / Q000378:metabolism*; D015726:Giant Cells / Q000166:cytology; D015497:HIV-1 / Q000502:physiology*; D006801:Humans; D008264:Macrophages / Q000166:cytology / Q000502:physiology* / Q000821:virology; D013601:T-Lymphocytes / Q000502:physiology* / Q000821:virology; D014771:Virion / Q000502:physiology; D014779:Virus Replication
D015686:Gene Products, env