Development and tolerization of hyperacute rejection in a transgenic mouse graft versus host model.

Background: The hyperacute rejection mediated by preexisting antibodies is a major impediment to the success of transplants across allogeneic and xenogeneic barriers. We report a new mouse model that allows us to not only monitor the sensitization of B cells mediating the hyperacute response but also validate therapeutic strategies for tolerizing them.

Model: The new model system uses 5C.C7,RAG2 T-cell receptor transgenic T cells and B10.S(9R),CD3[Latin Small Letter Open E] hosts for adoptive transfer experiments.

Results And Conclusions: In the allogeneic hosts, transgenic T cells expanded briefly before being chronically deleted. Once the deletion was initiated, a second graft of donor cells was used to assess a hyperacute response. The rapid rejection of the second cohort correlated with the appearance of donor-specific antibodies in the serum. Interestingly, chronically stimulated T cells were relatively resistant to hyperacute rejection, suggesting an explanation for the slower rejection kinetics of the first cohort even as the second cohort of identical donor cells was being hyperacutely rejected. Finally, we could tolerize the potential for a hyperacute response, by pretreating recipients with a single infusion of naive donor B cells before the first T-cell transfer. This treatment not only abrogated the development of a hyperacute response but also allowed the primary graft to survive in vivo for extended periods.