TLR2-mediated activation of innate responses in the upper airways confers antiviral protection of the lungs
Georgia Deliyannis, Chinn Yi Wong, Hayley A. McQuilten, Annabell Bachem, Michele Clarke, Xiaoxiao Jia, Kylie Horrocks, Weiguang Zeng, Jason Girkin, Nichollas E. Scott, Sarah L. Londrigan, Patrick C. Reading, Nathan W. Bartlett, Katherine Kedzierska, Lorena E. Brown, Francesca Mercuri, Christophe Demaison, David C. Jackson, Brendon Y. Chua
Georgia Deliyannis, Chinn Yi Wong, Hayley A. McQuilten, Annabell Bachem, Michele Clarke, Xiaoxiao Jia, Kylie Horrocks, Weiguang Zeng, Jason Girkin, Nichollas E. Scott, Sarah L. Londrigan, Patrick C. Reading, Nathan W. Bartlett, Katherine Kedzierska, Lorena E. Brown, Francesca Mercuri, Christophe Demaison, David C. Jackson, Brendon Y. Chua
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Research Article Infectious disease Therapeutics

TLR2-mediated activation of innate responses in the upper airways confers antiviral protection of the lungs

Abstract

The impact of respiratory virus infections on global health is felt not just during a pandemic, but endemic seasonal infections pose an equal and ongoing risk of severe disease. Moreover, vaccines and antiviral drugs are not always effective or available for many respiratory viruses. We investigated how induction of effective and appropriate antigen-independent innate immunity in the upper airways can prevent the spread of respiratory virus infection to the vulnerable lower airways. Activation of TLR2, when restricted to the nasal turbinates, resulted in prompt induction of innate immune–driven antiviral responses through action of cytokines, chemokines, and cellular activity in the upper but not the lower airways. We have defined how nasal epithelial cells and recruitment of macrophages work in concert and play pivotal roles to limit progression of influenza virus to the lungs and sustain protection for up to 7 days. These results reveal underlying mechanisms of how control of viral infection in the upper airways can occur and support the implementation of strategies that can activate TLR2 in nasal passages to provide rapid protection, especially for at-risk populations, against severe respiratory infection when vaccines and antiviral drugs are not always effective or available.

Authors

Georgia Deliyannis, Chinn Yi Wong, Hayley A. McQuilten, Annabell Bachem, Michele Clarke, Xiaoxiao Jia, Kylie Horrocks, Weiguang Zeng, Jason Girkin, Nichollas E. Scott, Sarah L. Londrigan, Patrick C. Reading, Nathan W. Bartlett, Katherine Kedzierska, Lorena E. Brown, Francesca Mercuri, Christophe Demaison, David C. Jackson, Brendon Y. Chua

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Figure 8

Epithelial cell protection in macrophage-depleted mice and in Let1 and LA-4 cells.

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Epithelial cell protection in macrophage-depleted mice and in Let1 and L...
(A) Mice (n = 5/group) were inoculated with 1 nmol of INNA-X or diluent and 1 day later received clodronate liposomes via the i.v. (200 μL) and i.n. route (50 μL) or were left untreated. All mice were challenged the next day with 500 PFU of Udorn IAV and 1 day after viral challenge the numbers of (B) macrophages and (C) NP+ CD45–CD31–EpCAM+ epithelial cells in nasal turbinates were analyzed. (D and E) 5 × 105 Let1 or 2 × 105 LA-4 cells were incubated in the presence or absence of INNA-X for 24 hours (D) or 18 hours (E) (n = 3–6/group). Cell monolayers were washed prior to challenge with Udorn IAV (MOI of 0.01). Culture supernatants were harvested 24 hours later and assayed to quantitate viral titers. (F) LA-4 cells were treated with 1 nmol of INNA-X prior to infection. Cells were harvested 8 hours after infection and stained for surface expression of HA, neuraminidase (NA), matrix-2 (M2) influenza viral proteins, and intracellular expression of NP. (G) INNA-X–treated LA-4 cells were lysed and proteins analyzed by reverse-phase liquid chromatography with tandem mass spectrometry (LC-MS/MS) after proteolytic digestion. Sample comparisons were performed using the MaxQuant proteomics platform to determine differentially expressed proteins (red) in INNA-X–treated cells relative to those treated with diluent. Statistical analysis was performed using (B–D and E) 1-way ANOVA with Tukey’s post hoc test and (F) Welch t test. *P < 0.05, **P < 0.01, ***P < 0.001.