Figure 2. Exogenous TGF-β₂ suppresses IFN-β release from virally infected (A) or poly IC exposed (B) PBEC cultures from non-asthmatic donors.

PBEC cultures were infected with RV1B (5000 TCID₅₀ units/10⁵ cells) (n = 10) or treated with poly IC (n = 5) in the presence or absence of TGF-β₂ which was used at 1 (black bars in B) or 10 ng/ml (panel A and grey bars in B). Culture supernatants were harvested 48 hours p.i (A) or 8 h post stimulation (B) and IFN-β protein levels were measured by ELISA. In B, the data are expressed as a % of control cultures treated with poly IC in the absence of TGF-β₂ (median (IQR) IFN-β release  = 346 (1135) and 369 (1390) pg/ml for cells treated with 1 or 10 µg/ml Poly IC, respectively. The data were analyzed using Wilcoxon’s rank sum test (A) or using a paired t-test for normally distributed data (B).