HIV-2 and SIV Infection of Nonprimate Cell Lines Expressing Human CD4: Restrictions to Replication at Distinct Stages

It is reported that CD4+ cat and rabbit cell lines are permissive to cell fusion induced by several HIV-2 and SIV strains, and distinct postpenetration blocks to viral replication are evident in rabbit and rodent cell lines.

Abstract

Mouse, rat, rabbit, cat, and mink cell lines expressing human CD4 restrict entry of HIV-1 strains at the cell surface. We now report that CD4+ cat and rabbit cell lines are permissive to cell fusion induced by several HIV-2 and SIV strains. CD4+ rat and mouse cells are only sensitive to HIV-2 and SIV fusion in the presence of active amphotericin B. HIV-2 and SIV replicate in CD4+ cat and CD4+ mink cells, but not in the CD4+ rabbit, rat, or mouse cells. These latter cell lines poorly express a transfected DNA molecular clone of HIV-2 DNA. CD4+ rat cells are sensitive to entry by HIV-2 (HTLV-1) pseudotypes and also to HIV-2 if amphotericin B is present. Early reverse transcription then occurs without subsequent viral gene expression, but the fusion-sensitive CD4+ rabbit cells are not permissive for HIV-2 reverse transcription. Our observations demonstrate (i) that the cat and mink cell lines express everything required except human CD4 for entry and replication by several HIV-2 and SIV strains and (ii) that distinct postpenetration blocks to viral replication are evident in rabbit and rodent cell lines.