Co-expression of CXCR4/fusin and Galactosylceramide in the Human Intestinal Epithelial Cell Line HT-29

AIDS. 1997 Sep;11(11):1311-8. doi: 10.1097/00002030-199711000-00004.

Abstract

Objective: To detect the expression CXCR4/fusin in human intestinal epithelial cells and to assess its potential role in the pathway of HIV-1 infection mediated by the alternative gp120 receptor galactosylceramide (GalCer).

Methods: GalCer+ (HT-29, HT-29/CD4+) and GalCer- (Caco-2/Cl2, Cl14 and Cl14/CD4+) human intestinal cell lines were analysed for CXCR4/fusin expression using the monoclonal antibody (MAb) 12G5. This MAb was then evaluated for its ability to inhibit HIV-1 infection in permissive cells. HIV-1 infection was measured by detection of p24 antigen, polymerase chain reaction amplification, and cocultivation with CD4+ cells.

Results: CXCR4/fusin was detected on the surface of HT-29 and HT-29/CD4+, but not on Caco-2/Cl2, Cl14 and Cl14/CD4+ cells. Ninety per cent of CXCR4/fusin+ HT-29 and HT-29/CD4+ cells co-expressed GalCer. Infection of HT-29 cells by laboratory isolates of HIV-1 was inhibited by both anti-GalCer and anti-CXCR4/fusin MAbs. Expression of CD4 rendered HT-29 cells sensitive to HIV-1(89.6), a macrophage-tropic isolate that does not recognize GalCer. The 12G5 MAb blocked HIV-1 infection of HT-29/CD4+ cells. In contrast, the expression of HIV-1 receptors, i.e., CD4 GalCer or both, into CXCR4/fusin-negative intestinal cells did not confer sensitivity to HIV-1 infection. The resulting receptor-positive cell lines could, however, bind HIV-1, whereas the original cell lines could not.

Conclusion: HIV-1 entry into human intestinal cells involves both GalCer and CXCR4/fusin. HIV-1 isolates such as 89.6 that are able to use CXCR4/fusin as coreceptor, but do not bind to GalCer, do not infect these cells. These data raise the possibility that CXCR4/fusin may function as a coreceptor for HIV-1 entry into CD4-/GalCer+ intestinal epithelial cells.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Antibodies, Blocking
  • Antibodies, Monoclonal
  • CD4-Positive T-Lymphocytes
  • Caco-2 Cells
  • Cells, Cultured
  • DNA, Viral / analysis
  • DNA, Viral / genetics
  • Fluorescent Antibody Technique, Indirect
  • Galactosylceramides / metabolism*
  • HIV Core Protein p24 / analysis
  • HIV Infections / metabolism*
  • HIV-1*
  • Humans
  • Intestinal Mucosa / cytology
  • Intestinal Mucosa / metabolism*
  • Membrane Proteins / immunology
  • Membrane Proteins / metabolism*
  • Membrane Proteins / physiology
  • Polymerase Chain Reaction
  • Receptors, CXCR4
  • Receptors, HIV / immunology
  • Receptors, HIV / metabolism*
  • Receptors, HIV / physiology
  • Sulfoglycosphingolipids / pharmacology

Substances

  • Antibodies, Blocking
  • Antibodies, Monoclonal
  • DNA, Viral
  • Galactosylceramides
  • HIV Core Protein p24
  • Membrane Proteins
  • Receptors, CXCR4
  • Receptors, HIV
  • Sulfoglycosphingolipids