SENSITIZED LYMPHOCYTES-B CONTRIBUTE TO ACUTE ALLOGRAFT-REJECTION

The contribution of sensitized B lymphocytes to second-set allograft rejection has been relatively ignored despite their regular appearance in rejecting allografts. This study presents evidence that adoptively transferred sensitized B lymphocytes accelerate the rate of acute allograft rejection in a sublethally irradiated rat cardiac allograft model. Donors of reconstituting B lymphocytes were sensitized with three consecutive ACI skin grafts. Transplantation of a heart from an ACI strain donor into a Lewis strain recipient (complete RT1 mismatch) results in rejection in 6.8 ± 0.3 days. When the allograft donor and recipient are irradiated with 650 cGy prior to transplantation, rejection occurs at 31.5 ± 3.0 days. Irradiated recipients reconstituted with 106 syngeneic sensitized splenic B cells reject their grafts in 20.1 ± 2.0 days, while reconstitution with 106 unsensitized syngeneic B cells has no effect on the rate of rejection (P = 0.0007). These data strongly suggest that sensitized B lymphocytes have a marked accelerating effect on the tempo of allograft rejection. © 1991.