FACS analysis to monitor BM engraftment and to search for injected CTL. Shown is the analysis of splenocytes isolated from C57BL/6 mice that either received BM from B10.A(4R) donors (BMT group) or BM and 1.5 × 10⁷ cloned allo-restricted CTL of BALB/c origin (BMT+CTL group). Splenocytes were stained with PE-labeled CD8 antibodies and with antibodies specific for the MHC class I alleles K^b, K^k, and L^d. The cells displayed in all panels were acquired through a lymphocyte gate set according to the size (FSC) and granularity (SSC) of lymphocytes. Shown is a representative analysis performed 6 weeks after BMT. Similar data were obtained with mice analyzed between 4 and 14 weeks after BMT.