CD4 confers susceptibility to human immunodeficiency virus type 1 infection in a rat fibroblast cell line.
A new model system is delineated that will enable study of CD4 cofactors and gp120 binding proteins other than CD4. We have previously described a nontransformed rat fibroblast cell line that can efficiently produce HIV-1 upon transfection with an HIV-1 infectious clone, in contrast to other nonhuman mammalian cell lines tested. In the present study we analyzed the susceptibility to HIV-1 infection of Rat2 cells expressing the human CD4 protein. We have used the mammalian expression vector pKS286, in which HIV-1 LTR drives the expression of the CD4 gene. We show that the Rat2 cell line, expressing the human CD4 (Rat2/CD4), is susceptible to fusion with and infection by HIV-1. The virus produced by the Rat2/CD4 cells was infectious. CD4 expression in the Rat2/CD4 was down-regulated over time, similarly to HIV-1 expression in HIV-1-transfected Rat2 cells. Transfection of the Rat2/CD4 cells with a tat expression vector reestablished the CD4 expression on the surface of those cells, as expected. We conclude that the expression of a gp120 binding protein on the Rat2 cells' surface suffices to render the Rat2 cells susceptible to HIV-1 infection.
Department of Pediatrics, Albert Einstein College of Medicine, Bronx, New York 10461, USA.
Y
Y
Mizrachi
A
A
Rubinstein
M
M
Golodner
K
K
Sakai
D J
DJ
Volsky
D000818:Animals; D015704:CD4 Antigens / Q000378:metabolism*; D002459:Cell Fusion; D005347:Fibroblasts / Q000821:virology*; D015699:HIV Envelope Protein gp120 / Q000378:metabolism*; D015497:HIV-1 / Q000472:pathogenicity*; D006801:Humans; D051381:Rats; D014162:Transfection
D015704:CD4 Antigens; D015699:HIV Envelope Protein gp120