Effect of rD-mPGPtide on donor chimerism in presensitized recipients. B6-Ly5.2 mice were presensitized (IP) with 2 × 10⁷ bm12 spleen cells 14 days before irradiation (700 cGy; body weight, 24 to 25 g) and transplanted with 10⁷ bm12 ATBM cells. One hour later, mice were treated with PBS (IV), anti-CD4 MoAb (ascites fluid 1:100 dilution; IP), or rD-mPGPtide (0.5 mg; IV), each at 0.2 mL. Recipient mice were injected again daily with the same reagents through day 3. Donor chimerism was analyzed 30 days after transplantation by two-color immunofluorescence flow cytometry using PE-anti-H2K^b and FITC-anti-CD45.1 (anti-Ly5.1) MoAb. The mean percentages of positive donor/host cells of four mice per group ±SD are presented for each individual treatment and are from one experiment representative of two performed with similar results. (▪) Donor; (▨) host.