Early kinetics of division and donor T-cell expansion after

TK T-cell infusion in lethally irradiated hosts.[B6 × FVB]F1 (semiallogeneic host)-irradiated or FVB (syngeneic host)-irradiated euthymic mice received 1 × 10⁷ FVB bone marrow cells supplemented with 1 × 10⁷ CFSE-labeled mature T cells from [hCD4 × TK] double-transgenic FVB mice. In treated groups, GCV was administered from hour 0 to hour 88 by intraperitoneal injection twice daily. (A) CFSE intensity of hCD4⁺ splenocytes was analyzed at different time points after grafting. Each histogram is representative of 3 mice. The peak of highest intensity on the log scale identifies parent generation of infused donor T cells. Peaks with decreased CFSE intensity represent daughter generations that have undergone division. (B) The number of donor T cells in spleens of grafted animals (n = 3) was evaluated at different time points by their expression of the hCD4 marker. Coefficient of variation of triplicates was less than 5%. ●, GCV; ○, no GCV.