RV-specific antibody responses in Tbet deficient and wild type mice.

<p>Wild type and Tbet-/- mice were infected intranasally with RV1B or sham infected with PBS. Blood was collected 14 days after infection. (A&B) RV1B-binding IgG2c (A) and IgG1 (B) in sera was measured by ELISA. (C) Neutralisation of RV1B infection of Ohio HeLa cells by pooled sera assessed by crystal violet cell viability staining. ATCC ctl: control reference guinea pig anti-sera. Top dashed line in C, uninfected cells control. Bottom dashed line in C, RV infected cells control. Data represent results from 5–6 pooled sera per treatment group in a single experiment, representative of 3 independent experiments.</p

Helper T cell responses in Tbet deficient and wild type mice.

<p>Wild type and Tbet-/- mice were infected intranasally with RV1B or sham infected with PBS. (A-D) Intranuclear flow cytometry staining for transcription factors Tbet (A), GATA-3 (B), RORγt (C) and FOXP3 (D) in CD3+CD4+ lung T cells, 2 and 7 days post-infection. (E-H) Intracellular flow cytometry staining for cytokines IFN-γ (E), IL-13 (F), IL-17A (G) and IL-10 (H) in lung CD3+CD4+ cells stimulated with PMA and ionomycin, on day 7 post-infection. (I-L) RNA was extracted from lung tissue harvested on day 7 post-infection and expression of IFN-γ (I), IL-13 (J), IL-17a (K) and IL-10 (L) mRNA was quantified by Taqman qPCR. n = 8–9 mice/group.***p<0.001, **p<0.01, *p<0.05, n.s. not significant.</p

Asthma-like airways inflammation is CD4+ T cell dependent.

<p>Tbet-/- mice were infected intranasally with RV1B or sham infected with PBS. In addition, mice were systemically depleted of CD4 expressing cells (anti-CD4), or treated with isotype control antibody (isotype) 3hrs prior to infection. Tissues were harvested at 7 days post-challenge. (A) Lung flow cytometry staining for CD3+CD4+ T cells. (B-D) Levels of cytokines IL-4 (B), IL-13 (C) and IL-17a (D) in lung tissue measured by Taqman qPCR. (E) Total BAL cell counts and (F) eosinophil counts in BAL measured by cytospin assay. (G) MUC5AC levels in BAL measured by ELISA. (H) Representative PAS staining for mucus in lung tissue sections. Scale bars 50μm. n = 12–15 mice/group (mice for which CD4+ cell depletion was not successful were excluded from all analyses (n = 5 of 30)). ***p<0.001, **p<0.01, *p<0.05, n.s. not significant.</p

Tbet Deficiency Causes T Helper Cell Dependent Airways Eosinophilia and Mucus Hypersecretion in Response to Rhinovirus Infection

Current understanding of adaptive immune, particularly T cell, responses to human rhinoviruses (RV) is limited. Memory T cells are thought to be of a primarily T helper 1 type, but both T helper 1 and T helper 2 memory cells have been described, and heightened T helper 2/ lessened T helper 1 responses have been associated with increased RV-induced asthma exacerbation severity. We examined the contribution of T helper 1 cells to RV-induced airways inflammation using mice deficient in the transcription factor T-Box Expressed In T Cells (Tbet), a critical controller of T helper 1 cell differentiation. Using flow cytometry we showed that Tbet deficient mice lacked the T helper 1 response of wild type mice and instead developed mixed T helper 2/T helper 17 responses to RV infection, evidenced by increased numbers of GATA binding protein 3 (GATA-3) and RAR-related orphan receptor gamma t (RORγt), and interleukin-13 and interleukin-17A expressing CD4+ T cells in the lung. Forkhead box P3 (FOXP3) and interleukin-10 expressing T cell numbers were unaffected. Tbet deficient mice also displayed deficiencies in lung Natural Killer, Natural Killer T cell and γδT cell responses, and serum neutralising antibody responses. Tbet deficient mice exhibited pronounced airways eosinophilia and mucus production in response to RV infection that, by utilising a CD4+ cell depleting antibody, were found to be T helper cell dependent. RV induction of T helper 2 and T helper 17 responses may therefore have an important role in directly driving features of allergic airways disease such as eosinophilia and mucus hypersecretion during asthma exacerbations