(A) Representative photomicrographs (magnification ×100 or ×400 [insets]) of sections from human skin grafts harvested from mice at day 28 after adoptive transfer of human PBMCs. (B) The number of graft-infiltrating human leukocytes at day 28 after adoptive transfer of PBMCs was quantified by IHC for cells stained with CD4, CD8, and FOXP3 in samples from mice treated with saline (n = 4), PEG (n = 3), FR104 (n = 4), or CTLA4-Ig (n = 4). This assay was repeated 3 times using different human PBMC donors. Data are shown as mean ± SEM. All data were analyzed by one-way ANOVA followed by Tukey’s multiple-comparisons test. *P < 0.05, **P < 0.01, ***P < 0.001.