HIV-1 Vaginal Transmission: Cell-Free or Cell-Associated Virus?

Authors

  • Victor Barreto-de-Souza,

    1. Section of Intercellular Interactions, Program in Physical Biology, Eunice Kennedy Shriver National Institute of Child Health and Human Development, Bethesda, MD, USA
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  • Anush Arakelyan,

    1. Section of Intercellular Interactions, Program in Physical Biology, Eunice Kennedy Shriver National Institute of Child Health and Human Development, Bethesda, MD, USA
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  • Leonid Margolis,

    Corresponding author
    1. Section of Intercellular Interactions, Program in Physical Biology, Eunice Kennedy Shriver National Institute of Child Health and Human Development, Bethesda, MD, USA
    • Correspondence

      Leonid Margolis, or Christophe Vanpouille, Program in Physical Biology, Eunice Kennedy Shriver, National Institute of Child Health and Human Development, Building 10, Room 9D58, 10 Center Drive, MSC 1855, Bethesda, MD 20892, USA.

      E-mails: margolis@helix.nih.gov; vanpouic@mail.nih.gov

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  • Christophe Vanpouille

    Corresponding author
    1. Section of Intercellular Interactions, Program in Physical Biology, Eunice Kennedy Shriver National Institute of Child Health and Human Development, Bethesda, MD, USA
    • Correspondence

      Leonid Margolis, or Christophe Vanpouille, Program in Physical Biology, Eunice Kennedy Shriver, National Institute of Child Health and Human Development, Building 10, Room 9D58, 10 Center Drive, MSC 1855, Bethesda, MD 20892, USA.

      E-mails: margolis@helix.nih.gov; vanpouic@mail.nih.gov

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Abstract

The vast majority of new HIV infections in male-to-female transmission occurs through semen, where HIV-1 is present in two different forms: as free and as cell-associated virus. In the female lower genital tract, semen mixes with female genital secretions that contain various factors, some of which facilitate or inhibit HIV-1 transmission. Next, HIV-1 crosses the genital epithelia, reaches the regional lymph nodes, and disseminates through the female host. Cervico-vaginal mucosa contains multiple barriers, resulting in a low probability of vaginal transmission. However, in some cases, HIV-1 is able to break these barriers. Although the exact mechanisms of how these barriers function remain unclear, their levels of efficiency against cell-free and cell-associated HIV-1 are different, and both cell-free and cell-associated virions seem to use different strategies to overcome these barriers. Understanding the basic mechanisms of HIV-1 vaginal transmission is required for the development of new antiviral strategies to contain HIV-1 epidemics.

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