Ken Rosenthal McMaster University AFRI-CAN 2013 Entebbe, Uganda SOLUBLE TOLL-LIKE RECEPTOR 2 (sTLR2) IS SIGNIFICANTLY ELEVATED IN HIV-1-INFECTED BREAST MILK AND INHIBITS HIV-1 INFECTION AND INFLAMMATION Ken Rosenthal McMaster University AFRI-CAN 2013 Entebbe, Uganda

Breastfeeding and HIV Exclusively breast feed (EBF) infants are 2 to 10-fold less likely to be infected compared to infants who are non-EBF.

Hypothesis Short-lived innate factors present in breast milk inhibit vertical transmission of HIV-1 from mother-to-child.

Cellular Localization of Toll-Like Receptors (TLRs)

Soluble TLR2: Breast Milk Recognizes a wide-range of ‘danger-associated’ molecules Decoy receptor that limits signaling through membrane-bound TLR2 High concentration in breast milk The biological significance of sTLR2 and HIV remains unknown

Schematic of sTLR2 cleavage and antibody binding

Increased sTLR2 in Milk of HIV-Infected Women Correlates with p24 Levels

Significantly Increased TLR Expression in Breast Milk Cells from HIV-Infected Nigerian Women

Significantly Elevated IL-15 & RANTES in Breast Milk from Uninfected Compared to HIV-infected Nigerian Women

Significant Decrease of Inflammatory Mediator IL-8 by sTLR2

Inhibition of HIV-1 Infection by sTLR2 produced in vitro A

Specific Binding of sTLR2 in Human Milk to HIV Proteins

CONCLUSIONS Depletion of sTLR2 in human milk resulted in significantly increased IL-8 production in U937 monocytes, HEK-293-TLR2 EC’s and human intestinal EC’s. sTLR2-depletion of milk led to significantly (P<0.001) increased HIV infection in vitro. sTLR2 produced in vitro from a TLR2-tranformed cell line significantly reduced cell-free R5 HIV infection and was reversed after neutralization by anti-TLR2 Abs. sTLR2 significantly reduced proinflammatory cytokine production in HIV-exposed cells. sTLR2 was significantly increased in milk of HIV-infected Nigerian women and correlated with p24 levels.

CONCLUSIONS Breast milk cells from HIV-infected Nigerian women have significantly increased expression of numerous Toll-Like Receptors (TLRs) compared to uninfected Nigerian women. Breast milk from uninfected Nigerian & Canadian women contains significantly increased levels of IL-15 and RANTES compared to HIV-infected breast milk. sTLR2 directly binds to specific HIV structural proteins. Overall, our data suggest that sTLR2 in human milk may be critical to infant health and prove beneficial in prevention of mother-to-child HIV transmission (PMTCT).

Acknowledgements Collaborators: Dr. Alash’le Abimiku Rosenthal Laboratory: Bethany Henrick Xiao-Dan Yao Kakon Nag Anna Drannik Sumiti Jain Jen Newton Amy Patrick Collaborators: Dr. Alash’le Abimiku Institute of Human Virology Cohort Participants in Hamilton & Nigeria Hamilton Midwives & Lactation Consultants Supported by:

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