2014 “Towards an HIV Cure” symposiumMelbourne

TLR2 stimulation promotes HIV-1 infection of CD4 T cellsby increasing the susceptibility of CCR6- T cells to infection

Jean-François Bolduc, M.Sc.CHU de Québec Research Centre and Université Laval’s Faculty of Medecine

Background

In this study, we investigated the effect of TLR2 ligation on the susceptiblity ofCCR6-/+ CD4 T cells to HIV-1 infection.

• Following infection, HIV-1 induces structural and immunological disruptions leading to bacterial translocation and release of microbial components in the bloodstream.

• Bacterial components may affect gut-homing CD4 T cells such as CCR6- and CCR6+, which are enriched in the gut mucosa and highly permissive to HIV-1 infection.

Gosselin, A. et al. Peripheral Blood CCR4+CCR6+ and CXCR3+CCR6+ CD4+ T Cells Are Highly Permissive to HIV-1 Infection. The Journal of Immunology 184, 1604–1616 (2010).

Monteiro, P. et al. Memory CCR6+CD4+ T Cells Are Preferential Targets for Productive HIV Type 1 Infection Regardless of Their Expression of Integrin 7. The Journal of Immunology 186, 4618–4630 (2011).

Shan, L. & Siliciano, R. F. Unraveling the relationship between microbial translocation and systemic immune activation in HIV infection. The Journal of Clinical Investigation 124, 2368–2371 (2014).

Methodology

Primary human resting CD4 T cells were purified by magnetic separationand stimulated for 72h with anti-CD3/CD28 antibodies +/- TLR2 ligand.

Methodology

Primary human activated CD4 T cells were infected for 24h with the complete R5 HIV-1-based reporter virusNL4-3-Bal-IRES-HSA.

HSA (heat-stable antigen) (CD24)

Murine origin protein expressed at the surface of the cells productively infected with fully competent virions

Imbeault, M., Lodge, R., Ouellet, M. & Tremblay, M. J. Efficient magnetic bead-based separation of HIV-1-infected cells using an improved reporter virus system reveals that p53 up-regulation occurs exclusively in the virus-expressing cell population. Virology 393, 160–167 (2009).

Methodology

CFSE proliferation assays and flow cytometry analysis have been performedto define and explain the effect of TLR2 ligation on the susceptibility of CCR6-/+ CD4 T cells.

Results

Compared to CD3/CD28 stimulation, TLR2 ligation increases the % of infected (HSA+) CD4 T cells and viral p24 production.

Results

TLR2 ligation does not affect uninfected CD4 T cell proliferation.

Results

TLR2 ligation does not affect uninfected CD4 T cell distribution.

Results

TLR2 ligation increases the susceptibility of CCR6- cells to HIV-1 infection to levels observed in the CCR6+ subset,while CD3/CD28 stimulation by itself increases infection of CCR6+ cells.

Results

CD4/CCR5/α4 cell surface expression is higher on CCR6+ than on CCR6- CD4 T cells, but is not affected by TLR2 ligation.

Conclusion

• TLR2 stimulation could play a significant role in early HIV-1 infection by abolishing post-entry barriers.

• The effect of TLR2 ligation on HIV-1 infection susceptibility is more pronounced on CCR6- compared to CCR6+ CD4 T cells subset.

• These results highlight the possible importance of early interactions between HIV-1 and gut microbiota and could lead to novel therapies seeking to block those interactions.

Alejandro Martin Gomez,

Lic.

Acknowledgements

Michel J.Tremblay, Ph.D.

Director

Corinne Barat, Ph.D.Réjean Cantin, Ph.D.Michel Ouellet, Ph.D.

Adjunct ProfessorsClélia Dental, Ph.D.Alexandre Deshière, Ph.D.Alize Proust, Ph.D.

Postdoctoral fellows

Ph.D. student

Sylvie Méthot, B.Sc.

Scientific editor

Research assistantMarc-André Roy, B.Sc.

Lab technicianCaroline Côté, T.M.

Questions