HIV-1 specific IgA detected in vaginal secretions of HIV uninfected women participating in a microbicide trial in Southern Africa are primarily directed toward gp120 and gp140 specificities

• Published in: PloS one 2014-07, Vol.9 (7), p.e101863-e101863
• Main Authors: Seaton, Kelly E, Ballweber, Lamar, Lan, Audrey, Donathan, Michele, Hughes, Sean, Vojtech, Lucia, Moody, M Anthony, Liao, Hua-Xin, Haynes, Barton F, Galloway, Christine G, Richardson, Barbra A, Karim, Salim Abdool, Dezzutti, Charlene S, McElrath, M Juliana, Tomaras, Georgia D, Hladik, Florian
• Format: Article
• Language: English
• Subjects: Acquired immune deficiency syndrome; AIDS; Analysis of Variance; Anti-infective agents; Anti-Infective Agents - immunology; Anti-Infective Agents - therapeutic use; Antibodies; Antigens; Biology and Life Sciences; Bodily Secretions - immunology; Bodily Secretions - virology; Cancer; Cohort Studies; Dacron; Disease prevention; env Gene Products, Human Immunodeficiency Virus - immunology; Female; Glycoprotein gp120; Glycoprotein gp41; Gynecology; Health risk assessment; HIV; HIV Antibodies - immunology; HIV Envelope Protein gp120 - immunology; HIV Infections - diagnosis; HIV Infections - immunology; HIV Infections - prevention & control; HIV Seronegativity - immunology; HIV Seropositivity - immunology; HIV-1 - drug effects; HIV-1 - immunology; Human immunodeficiency virus; Humans; Immune response; Immunity, Mucosal - drug effects; Immunity, Mucosal - immunology; Immunoglobulin A; Immunoglobulin A - immunology; Immunoglobulin G; Immunoglobulin G - immunology; Immunoglobulins; Immunology; Infections; Infectious diseases; Medical research; Medicine; Medicine and health sciences; Mucosal immunity; Obstetrics; Pilot Projects; Polyethylene terephthalate; Sampling; Secretions; South Africa; Specimen Handling - instrumentation; Specimen Handling - methods; Vaccines; Vagina; Vagina - immunology; Vagina - virology
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0101863

Many participants in microbicide trials remain uninfected despite ongoing exposure to HIV-1. Determining the emergence and nature of mucosal HIV-specific immune responses in such women is important, since these responses may contribute to protection and could provide insight for the rational design of HIV-1 vaccines. We first conducted a pilot study to compare three sampling devices (Dacron swabs, flocked nylon swabs and Merocel sponges) for detection of HIV-1-specific IgG and IgA antibodies in vaginal secretions. IgG antibodies from HIV-1-positive women reacted broadly across the full panel of eight HIV-1 envelope (Env) antigens tested, whereas IgA antibodies only reacted to the gp41 subunit. No Env-reactive antibodies were detected in the HIV-negative women. The three sampling devices yielded equal HIV-1-specific antibody titers, as well as total IgG and IgA concentrations. We then tested vaginal Dacron swabs archived from 57 HIV seronegative women who participated in a microbicide efficacy trial in Southern Africa (HPTN 035). We detected vaginal IgA antibodies directed at HIV-1 Env gp120/gp140 in six of these women, and at gp41 in another three women, but did not detect Env-specific IgG antibodies in any women. Vaginal secretions of HIV-1 infected women contained IgG reactivity to a broad range of Env antigens and IgA reactivity to gp41. In contrast, Env-binding antibodies in the vaginal secretions of HIV-1 uninfected women participating in the microbicide trial were restricted to the IgA subtype and were mostly directed at HIV-1 gp120/gp140.