Influence of Fas/FasL interactions on donor T-cell expansion. Expansion of donor T cells obtained from B6.SJL, gld (FasL-deficient), or lpr (Fas-deficient) mice after transplantation in B6AF1 or B6.SAF1 recipients. Three-color staining was performed with the following fluorochrome-conjugated antibodies: anti-Ly5.1 or anti-Ly5.2, anti-CD4 or anti-CD8, and anti-Thy1.1 or anti-Thy1.2. On day 16, the number of donor-derived CD8⁺ T cells was greater with lpr donors than with B6.SJL donors (***P < .005).