Allosensitization results in antibody-mediated donor BM rejection. (A,C) B6 mice were lethally irradiated on day −1 (8.0 Gy) and infused with 20 × 106 (A) or 40 × 106 (C) BALB/c BM on day 0. Mice were primed at various times prior to BMT by the intraperitoneal administration of 20 × 106 BALB/c splenocytes. One group received anti-CD4, anti-CD8, and anti-NK mAbs around the time of transplantation (A). Survival is shown. (A) n = 16 to 26/group; data from 2 to 3 separate experiments with similar results were pooled. (C) n = 5/group. (B,D) Serum was collected from BALB/c-primed B6 mice after the indicated interval, diluted, and incubated with BALB/c thymocytes. Cells were washed and incubated with FITC-conjugated goat anti–mouse Ig Ab and analyzed by flow cytometry. Overlay histograms indicate alloantibody in diluted serum from 5 different mice binding to BALB/c thymocytes. Negative control of FITC-conjugate binding to thymocytes in absence of serum is indicated by the thin dotted line. Average mean fluorescent intensity (MFI) is listed for panel D. (D) *P < .05 versus primed day −28; n = 5. Each bold line represents a different mouse.
