1. Tenascin-C is an innate broad-spectrum, HIV-1-neutralizing protein in breast milk.
- Author
-
Fouda GG, Jaeger FH, Amos JD, Ho C, Kunz EL, Anasti K, Stamper LW, Liebl BE, Barbas KH, Ohashi T, Moseley MA, Liao HX, Erickson HP, Alam SM, and Permar SR
- Subjects
- Acquired Immunodeficiency Syndrome prevention & control, Blotting, Western, Cell Line, Chromatography, Ion Exchange, Dose-Response Relationship, Drug, Female, Humans, Immunoprecipitation, Inhibitory Concentration 50, Mass Spectrometry, Tenascin metabolism, Viral Envelope Proteins metabolism, Acquired Immunodeficiency Syndrome transmission, HIV-1 drug effects, Infectious Disease Transmission, Vertical prevention & control, Milk, Human chemistry, Tenascin pharmacology
- Abstract
Achieving an AIDS-free generation will require elimination of postnatal transmission of HIV-1 while maintaining the nutritional and immunologic benefits of breastfeeding for infants in developing regions. Maternal/infant antiretroviral prophylaxis can reduce postnatal HIV-1 transmission, yet toxicities and the development of drug-resistant viral strains may limit the effectiveness of this strategy. Interestingly, in the absence of antiretroviral prophylaxis, greater than 90% of infants exposed to HIV-1 via breastfeeding remain uninfected, despite daily mucosal exposure to the virus for up to 2 y. Moreover, milk of uninfected women inherently neutralizes HIV-1 and prevents virus transmission in animal models, yet the factor(s) responsible for this anti-HIV activity is not well-defined. In this report, we identify a primary HIV-1-neutralizing protein in breast milk, Tenascin-C (TNC). TNC is an extracellular matrix protein important in fetal development and wound healing, yet its antimicrobial properties have not previously been established. Purified TNC captured and neutralized multiclade chronic and transmitted/founder HIV-1 variants, and depletion of TNC abolished the HIV-1-neutralizing activity of milk. TNC bound the HIV-1 Envelope protein at a site that is induced upon engagement of its primary receptor, CD4, and is blocked by V3 loop- (19B and F39F) and chemokine coreceptor binding site-directed (17B) monoclonal antibodies. Our results demonstrate the ability of an innate mucosal host protein found in milk to neutralize HIV-1 via binding to the chemokine coreceptor site, potentially explaining why the majority of HIV-1-exposed breastfed infants are protected against mucosal HIV-1 transmission.
- Published
- 2013
- Full Text
- View/download PDF