BPI transgenic T-cell-derived exosomes stimulate IL-β production from macrophages. (A and B) Flow cytometry analyses of IL-1β-producing T cells (CD3-gated cells; A) and IL-1β-producing myeloid-lineage cells (CD11b-gated cells; B) from the lymph node of 12-week-old wild-type (WT) or Lck-BPI transgenic mice (C) Immunohistochemical staining of FITC-conjugated anti-IL-1β antibody (green) and PE-conjugated anti-CD11b antibody (Red) in the paraffin-embedded sections of the liver, kidney, and palm from wild-type and Lck-BPI Tg mice. Cell nuclei were stained with DAPI (blue). Scale bars, 25 µm. Mean ± SEM of relative fluorescence intensity values (FITC versus DAPI or PE versus DAPI, 10-6/um2) from 5 images are shown at the bottom of individual panels. (D) Real-time PCR of IL-β, IL-6, and TNF-α mRNA levels in wild-type BMDMs stimulated with T-cell-derived exosomes from wild-type or Lck-BPI Tg T cells. Means ± SD are shown. **, P value < 0.01 (two-tailed Student's t-test). Data shown (A-D) are representatives of three independent experiments.