Diminution of CD4 surface protein but not CD4 messenger RNA levels in monocytic cells infected by HIV-1.
As expected, the productive infection of several monocytic cell lines by HIV-1 led to a diminution of cell-surface CD4 antigen. However, unlike findings reported for HIV-1-infected T cells, this decrease was not accompanied by a similar reduction in levels of CD4 transcripts. OKT4 monoclonal antibodies (MAbs) to CD4 were used in immunoprecipitation experiments to show that intracellular CD4 levels were diminished in U-937 monocytic cells that had been infected by HIV-1. These MAbs also coprecipitated viral gp120, indicating that CD4-gp120 complexes are present in infected monocytes. Our results therefore demonstrate that cell-surface down-modulation of CD4 is exclusively a post-transcriptional event in HIV-1 infected monocytic cells. These data suggest that HIV-1-mediated depletion of cell-surface CD4 in monocytes does not involve transcript down-modulation as has been reported in T lymphocytes.
Geleziunas
R
R
McGill AIDS Centre, McGill University, Montréal, Canada.
Bour
S
S
Boulerice
F
F
Hiscott
J
J
Wainberg
M A
MA
D000911:Antibodies, Monoclonal / Q000276:immunology; D015152:Blotting, Northern; D015704:CD4 Antigens / Q000235:genetics / Q000276:immunology / Q000378:metabolism*; D002460:Cell Line; D003720:Densitometry; D015536:Down-Regulation; D005434:Flow Cytometry; D015699:HIV Envelope Protein gp120 / Q000378:metabolism; D015497:HIV-1 / Q000502:physiology*; D006801:Humans; D009000:Monocytes / Q000276:immunology / Q000378:metabolism / Q000382:microbiology*; D011233:Precipitin Tests; D012333:RNA, Messenger / Q000378:metabolism*; D012367:RNA, Viral / Q000378:metabolism*; D013601:T-Lymphocytes / Q000276:immunology / Q000378:metabolism / Q000382:microbiology*; D014158:Transcription, Genetic; D014779:Virus Replication
D000911:Antibodies, Monoclonal; D015704:CD4 Antigens; D015699:HIV Envelope Protein gp120; D012333:RNA, Messenger; D012367:RNA, Viral