Previous Article | Next Article ![]()
J. Virol., 09 1996, 6044-6053, Vol 70, No. 9
BK Chen, RT Gandhi and D Baltimore
The human immunodeficiency virus type 1 (HIV-1) genes vpu, env, and nef
have all been implicated in modulating the levels of cell surface CD4 on
infected cells. To quantitatively assess the relative contribution of each
gene product to the regulation of CD4 during HIV infection of Jurkat T
cells and peripheral blood mononuclear cells, we have developed an
infectious HIV reporter system which expresses different combinations of
these genes. To distinguish infected cells in the early or late stages of
infection from uninfected cells, these viruses were designed to express
human placental alkaline phosphatase with the kinetics of either early or
late viral genes. Flow cytometry to detect placental alkaline phosphatase
and CD4 in infected cells showed that vpu, env, and nef are independently
capable of down-modulation of CD4. As predicted by their respective
expression patterns, nef down- modulated CD4 rapidly during the early phase
of virus infection whereas vpu and env functioned late in the infection. In
both Jurkat cells and peripheral blood mononuclear cells, a combination of
the three genes was more efficient than any one or two genes, demonstrating
that all three genes are required to achieve maximal CD4 down-modulation.
In primary cells, down-modulation of CD4 was less efficient than in Jurkat
cells and there was a stronger dependence on nef function for reducing cell
surface CD4. HIV therefore has three genes that are able to independently
down-modulate CD4; together, they can eliminate the bulk of cell surface
CD4.
Copyright © 1996, American Society for Microbiology
CD4 down-modulation during infection of human T cells with human immunodeficiency virus type 1 involves independent activities of vpu, env, and nef
Department of Biology, Massachusetts Institute of Technology, Cambridge 02139, USA.
This article has been cited by other articles:
| J. Bacteriol. | Mol. Cell. Biol. | Microbiol. Mol. Biol. Rev. |
|---|
| Clin. Vaccine Immunol. | ALL ASM JOURNALS |
|---|