The second extracellular loop of CXCR4 is involved in CD4-independent entry of human immunodeficiency virus type 2

J Gen Virol. 1998 Jul:79 ( Pt 7):1793-9. doi: 10.1099/0022-1317-79-7-1793.

Abstract

Human immunodeficiency virus type 2 (HIV-2) strains that infect cells in the absence of cellular CD4 emerge spontaneously in vitro after culture in CD4+ T-cell lines. The HIV-2ROD/B strain can use the CXCR4 chemokine receptor for efficient entry into CD4+ cells. Here we have shown that the rat homologue of CXCR4, in the absence of CD4, failed to mediate CD4-independent entry by ROD/B. Furthermore, using rat-human chimeric CXCR4 receptors we have demonstrated that the second extracellular loop (E2) of human CXCR4 is critical for HIV-2 infection of CD4+ cells. E2 is also important for HIV-1 infection of CD4+ cells. Our results therefore indicate that the role of E2 in HIV entry is conserved for HIV-1 and HIV-2 and for infection in the presence or absence of CD4.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Binding Sites
  • CD4 Antigens / metabolism*
  • Cats
  • Cell Line
  • Chemokine CXCL12
  • Chemokines, CXC / metabolism
  • HIV-1 / metabolism
  • HIV-1 / physiology
  • HIV-2 / metabolism*
  • HIV-2 / physiology
  • Humans
  • Rats
  • Receptors, CXCR4 / genetics
  • Receptors, CXCR4 / metabolism*
  • Recombinant Fusion Proteins / genetics
  • Recombinant Fusion Proteins / metabolism

Substances

  • CD4 Antigens
  • CXCL12 protein, human
  • Chemokine CXCL12
  • Chemokines, CXC
  • Receptors, CXCR4
  • Recombinant Fusion Proteins