Figure 4.

Cytokine-producing T cells are engaged in contact with APCs. C57Bl/6 mice were treated with HDM/CT on d0 and re-challenged with HDM on d7. On d9, perfusion-fixed tracheas were collected for confocal microscopic analysis. (A, B) Visualization of an effector T-cell/DC cluster in a tracheal whole mount. Boxed regions in A (upper panels, bars=50μm) were enlarged (lower panels, bars=10μm) and displayed as XY, XZ and YZ representations (B) to show an IL-17⁺ T-cell in direct contact with an APC (arrow). (C, D) Visualization of an effector T-cell/DC cluster in a frozen cross-section of the tracheal mucosa. Boxed region in C (left panel, bar=50μm) is shown also as separate channels (right panels, bars=10μm) and displayed as XY, XZ and YZ representations (D) to indicate an IL-13⁺ T cell in direct contact with an APC (arrow). B and D show single slices, the position of slicers is indicated by tick marks. (E, F) Quantitative analysis showing % of cytokine-positive vs. cytokine-negative cells in contact with an APC. Between 74-104 tracheal cytokine-positive or randomly selected cytokine-negative T cells were analyzed; n=7-8 mice for E, n=6 mice for F (*:p < 0.05; ***:p < 0.001 as determined using Mann-Whitney test). Results of a single experiment are shown.