Modulation of CD28 in vivo reduces allogenic T-cell proliferation in GVHD.
Spleen mononuclear cells from LEW.1A rats (3 × 108) were labeled with CFSE and transplanted intravenously into irradiated LEW.1W. Recipients received intraperitoneally 1 mg control IgG or modulating anti–rat CD28 JJ319 or 0.5 mg CTLA4 immunoglobulin at days 0 and 2. At 3 days, spleen lymphocytes were harvested and analyzed by FACS after gating on CD4+ cells. (A) The black histogram indicates the CFSE profile of control-treated recipients gated on CD4+ T cells; and the white histogram, FL1 signal of recipient CD4+ T cells from nontransplanted control. Y axis shows cell number per fluorescence channel. X axis shows halving of fluorescence after each mitosis. (B) The histogram indicates the measurement of alloreactive CD4+ T cells according to their division status. Data are mean ± SD from 3 animals. (C, D) Expression of CD25 and binding of Annexin V on proliferating CFSE+ cells. (▪) Recipients treated with control IgG. (▵) Recipients treated with CTLA4 immunoglobulin. (▴) Recipients treated with anti-CD28. Nb indicates the number of mitosis according to fluorescence intensity halving.
