1. 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

2. 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.

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

5. Cellular Localization of Toll-Like Receptors (TLRs)

6. 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

7. Schematic of sTLR2 cleavage and antibody binding

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

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

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

11. Significant Decrease of Inflammatory Mediator IL-8 by sTLR2

12. Inhibition of HIV-1 Infection by sTLR2 produced in vitroA

13. Specific Binding of sTLR2 in Human Milk to HIV Proteins

14. 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.

15. 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).

16. 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:

17. Questions?