Radiation dose titration of the haploidentical strain combination (B6D2)F₁ → (B6CB)F₁ . (B6CB)F₁ mice (n = 3 to 5; body weight, 25 to 29 g) were irradiated with the indicated γ-ray dose and received a transplant of allogeneic (B6D2)F₁ ATBM (10⁷ cells) on day 0. Splenocytes from recipients were analyzed for donor chimerism on day 30 post-BMT by two-color immunofluorescence flow cytometry with FITC-anti-H2K^k and PE-anti-H2K^d MoAb. The data ±SD shown are from one experiment representative of two performed with this strain combination. (▪) Donor; (▨) host.