AIDS

Skip Navigation LinksHome > September 10, 2014 - Volume 28 - Issue 14 > Soluble Toll-like receptor 2 is significantly elevated in HI...
AIDS:
doi: 10.1097/QAD.0000000000000381
Basic Science

Soluble Toll-like receptor 2 is significantly elevated in HIV-1 infected breast milk and inhibits HIV-1 induced cellular activation, inflammation and infection

Henrick, Bethany M.a; Yao, Xiao-Dana; Drannik, Anna G.a; Abimiku, Alash’leb; Rosenthal, Kenneth L.a; the INFANT Study Team

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Abstract

Objectives: We previously demonstrated that immunodepletion of soluble Toll-like receptor 2 (sTLR2) from human breast milk significantly increased HIV infection in vitro. The aims of this study were to characterize sTLR2 levels in breast milk from HIV-infected and uninfected women, and identify a mechanism by which sTLR2 inhibits HIV-induced cellular activation and infection.

Design: Blinded studies of breast milk from HIV-infected and uninfected Nigerian and Canadian women were evaluated for levels of sTLR2, proinflammatory cytokines and viral antigenemia. In-vitro experiments were conducted using cell lines to assess sTLR2 function in innate responses and effect on HIV infection.

Results: Breast milk from HIV-infected women showed significantly higher levels of sTLR2 than uninfected breast milk. Further, sTLR2 levels correlated with HIV-1 p24 and interleukin (IL)-15, thus suggesting a local innate compensatory response in the HIV-infected breast. Given the significantly higher levels of sTLR2 in breast milk from HIV-infected women, we next demonstrated that mammary epithelial cells and macrophages, which are prevalent in milk, produced significantly increased levels of sTLR2 following exposure to HIV-1 proteins p17, p24 and gp41 or the TLR2 ligand, Pam3CSK4. Our results also demonstrated that sTLR2 physically interacts with p17, p24 and gp41 and inhibits HIV-induced nuclear factor kappa-light-chain-enhancer of activated B cells activation, and inflammation. Importantly, binding of sTLR2 to HIV-1 proteins inhibited a TLR2-dependent increase in chemokine receptor 5 expression, thus resulting in significantly reduced HIV-1 infection.

Conclusion: These results indicate novel mechanisms by which sTLR2 plays a critical role in inhibiting mother-to-child HIV transmission.

© 2014 Lippincott Williams & Wilkins, Inc.

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