Figure 5. The alloreactive T cell response to single class I MHC mismatched cardiac allografts in wild-type C57BL/6 recipients is not restricted by CD25⁺ T cells.

(A) Groups of wild-type C57BL/6 and CCR5^−/− mice received B6.K^d cardiac allografts. The wild-type mice were treated with control rat IgG or anti-CD25 mAb, 0.5 mg on day −1 and 0.25 mg of Ab on days 1, 3, 5, 7, and 9 post-transplant. On day 10 post-transplant, grafts were harvested, weighed, digested, and single cell suspensions stained with anti-CD4, anti-CD25 and anti-Foxp3 mAb and analyzed by flow cytometry. The data shown indicate numbers of graft infiltrating CD4⁺FoxP3⁺ cells/mg graft tissue for five mice per group and are representative of two separate experiments. (B) Groups of wild-type C57BL/6 mice were treated with control rat IgG (—●— n = 7) or anti-CD25 mAb i.p. (—◯— n = 7) and received B6.K^d cardiac allografts. Cardiac allograft survival was monitored daily by abdominal palpation and rejection was confirmed visually by laparotomy. (C) On day 10 post-transplant, spleen cell suspensions from wild-type C57BL/6 recipients treated with control rat IgG or anti-CD25 mAb and B6.CCR5^−/− recipients of B6.K^d cardiac allografts were depleted of CD4 T cells and ELISPOT assays were performed on day 10 post-transplant to enumerate donor-reactive IFN-γ producing CD8 T cells. Data indicate mean numbers of donor-reactive CD8 T cells producing IFN-γ ± SEM and are representative of two independent experiments. *p < 0.05.