Human immunodeficiency virus type 2 infection and fusion of CD4-negative human cell lines: induction and enhancement by soluble CD4
Clapham, P.R.; McKnight, A.; Weiss, R.A.
Journal of Virology 66(6): 3531-3537
ISSN/ISBN: 0022-538X PMID: 1583722 Accession: 040313567
We describe human immunodeficiency type 2 (HIV-2) strains which induce cell-to-cell fusion and infect certain CD4- human cell lines. Soluble CD4 (sCD4) induces or enhances fusion by most HIV-2 strains tested. Soluble CD4-immunoglobulin G chimeras and conjugates of sCD4 and antibody to the third domain of CD4 block HIV-2 fusion of CD4- cells. We conclude that HIV-2 can enter CD4- cells via an alternative cell surface receptor to CD4. While some strains entered efficiently, others retained a dependency on an interaction with sCD4 to initiate changes in the virion envelope required for membrane fusion.