Reconstitution of ZAP-70^−/− mice after intravenous and intrathymic histocompatible progenitor cell transplantation in the absence and presence of conditioning. ZAP-70^−/− mice were transplanted with histocompatible WT BM progenitors, administered by either intravenous or intrathymic routes, in nonconditioned or busulphan/cyclophosphamide preconditioned hosts. (A) The presence of CD45.1 donor cells in the thymi of reconstituted mice was assessed 25 weeks after transplantation. Representative dot plots showing the percentages of CD45.1+ cells are presented. Control stainings show CD45.1 expression in WT donor mice and ZAP-70^−/− recipients. The percentages of thymocytes in the boxed quadrants are noted (upper panels). The CD4/CD8 phenotype of thymocytes in the boxed quadrants is presented in the lower panels. The percentages of DN, DP, and SP thymocytes are indicated. (B) The relative proportion of donor cells in lymph nodes of ZAP-70^−/− mice transplanted by intravenous and intrathymic routes, in the absence or presence of conditioning (cond), was assessed. The presence of donor cells was monitored 25 weeks after transplantation with each point representing data from 1 mouse. The mean percentage of donor cells in each condition is indicated with a line. (C) The presence of donor CD3+ and CD19+ cells in lymph nodes of preconditioned ZAP-70^−/− recipients transplanted by intravenous and intrathymic routes was monitored by flow cytometry. The percentages of CD3+ and CD19+ cells are indicated in each quadrant, and staining of WT donor and ZAP-70^−/− recipients are presented (upper panels). The percentages of donor-derived CD19+ B cells were assessed as a function of CD45.1 expression, and data for representative mice in each group are shown.