Transgenic Vγ6+/+ mice repeatedly exposed to B. subtilis develop less lung fibrosis. A, Representative trichrome staining of lungs from transgenic Vγ6+/+, wt C57BL/6, and TCRδ−/− mice repeatedly treated with inhaled B. subtilis or PBS for 4 consecutive weeks is shown. Data shown represent at least five mice from at least two separate experiments (original magnification × 100). B, Quantification of collagen content using Sirius red colorimetric assay in the lungs of individual transgenic Vγ6+/+ (+/+), wt C57BL/6 (wt), and TCRδ−/− (δ−/−) mice treated with B. subtilis (Bsub) or PBS for 4 consecutive weeks. Data were compiled from at least two separate experiments.