Pseudotypes of vesicular stomatitis virus-bearing envelope antigens of certain HIV-1 strains permissively infect human syncytiotrophoblasts cultured in vitro: implications for in vivo infection of syncytiotrophoblasts by cell-free HIV-1

J Med Virol. 2001 Aug;64(4):387-97. doi: 10.1002/jmv.1063.

Abstract

Intrauterine infection of the fetus is clearly an important mode of vertical transmission of human immunodeficiency virus type 1 (HIV-1). The syncytiotrophoblast layer of the human placenta must be traversed by HIV-1 in order to reach underlying cells and fetal capillaries. Although HIV-1 has been detected in the syncytiotrophoblast layer in situ, there is conflicting evidence regarding infection of syncytiotrophoblast cells with cell-free virus. The phenotypic mixing between HIV-1 and vesicular stomatitis virus (VSV) has been exploited to assay the susceptibility of human term syncytiotrophoblast cells to penetration by various strains of HIV-1. VSV(HIV-1(IIIB)) and VSV(HIV-1(Ba-L)) pseudotypes were found to enter syncytiotrophoblast cells. In contrast, VSV pseudotyped with envelope glycoproteins of RF, MN, or Ada-M strains of HIV-1 did not infect syncytiotrophoblasts. Plating efficiency of VSV(HIV-1(IIIB)) and VSV(HIV-1(Ba-L)) was 10-fold lower on syncytiotrophoblasts than on T-cells and macrophages, respectively. Incubation of VSV(HIV-1(IIIB)) and VSV(HIV-1(Ba-L)) viruses with appropriate HIV-1 neutralizing sera before infection strongly inhibited entry of pseudotyped VSV into syncytiotrophoblast cells. These findings demonstrated that infection of syncytiotrophoblasts with VSV(HIV-1) pseudotypes was mediated by Env from IIIB and Ba-L strains of HIV-1. Monoclonal antibodies (MAb) to CD4, CXCR4, CCR5, and CCR3 were tested for their ability to block VSV(HIV-1) infection of syncytiotrophoblast cells. Neither the anti-CD4 nor the anti-CXCR4, anti-CCR5, and anti-CCR3 MAb had any inhibitory effect on infection of syncytiotrophoblast cells with VSV(HIV-1) pseudotypes. Results from this study suggest that cell-free HIV-1 can enter syncytiotrophoblasts and the susceptibility of these cells to penetration by the virus is strain dependent. Pseudotype infection merely demonstrates that the first steps in HIV-1 replication are possible in syncytiotrophoblast cells.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Antibodies, Monoclonal / pharmacology
  • CD4 Antigens / immunology
  • Cell Line
  • Cytopathogenic Effect, Viral
  • HIV Antigens / immunology
  • HIV Infections / transmission
  • HIV-1 / genetics
  • HIV-1 / immunology*
  • Humans
  • Immune Sera / pharmacology
  • Infectious Disease Transmission, Vertical
  • Macrophages / virology
  • Receptors, CCR3
  • Receptors, CCR5 / immunology
  • Receptors, CXCR4 / immunology
  • Receptors, Chemokine / immunology
  • T-Lymphocytes / virology
  • Time Factors
  • Trophoblasts / drug effects
  • Trophoblasts / virology*
  • U937 Cells
  • Vesicular stomatitis Indiana virus / genetics
  • Vesicular stomatitis Indiana virus / immunology
  • Vesicular stomatitis Indiana virus / physiology*
  • Virus Replication

Substances

  • Antibodies, Monoclonal
  • CCR3 protein, human
  • CD4 Antigens
  • HIV Antigens
  • Immune Sera
  • Receptors, CCR3
  • Receptors, CCR5
  • Receptors, CXCR4
  • Receptors, Chemokine