Correlation between cell surface CD47 density and DST effectiveness. Bm1 mice received a single injection of 1×107 splenocytes (i.e., DST) from GFP-transgenic WT (CD47+/+), CD47 heterozygous (CD47+/−) or CD47 KO (CD47−/−) B6 mice 7 days prior to donor skin grafting. Untreated bm1 mice were used as non-DST controls. (A) Flow cytometry profiles showing CD47 density on white blood cells from WT, CD47+/− and CD47−/− mice. MFI, mean fluorescent intensity. (B) Levels (mean±SDs) of donor chimerism (i.e., % GFP+ cells) in white blood cells measured by flow cytometry at the indicated times. (C) Donor skin graft survival. (D) Anti-donor (B6; left) and anti-3rd party (B10A; right) MLR of T cells purified from the spleens of non-DST controls and DST recipients 7 days after DST (n=3 per group). ***P<0.001; N.S. not significant.