Background: We investigated whether blockade of tumor necrosis factor receptor-ligand pathways could generate regulatory cells induced by intratracheal delivery of alloantigen.
Methods: CBA (H-2k) mice were pretreated with intratracheal delivery of splenocytes (1x10(7)) from C57BL/10 (H-2b) mice and intraperitoneal administration of monoclonal antibody (mAb) specific for CD70, CD134 ligand (CD134L), CD153, or CD137L. Seven days later, C57BL/10 hearts were transplanted into pretreated CBA mice. Some naive CBA mice underwent adoptive transfer of splenocytes (5x10(7)) from pretreated CBA mice and transplantation of a C57BL/10 heart on the same day.
Results: Untreated CBA mice rejected C57BL/10 cardiac grafts acutely (median survival time [MST] 12 days). Pretreatment with intratracheal delivery of C57BL/10 donor splenocytes prolonged graft survival significantly (MST 84 days). Mice given intratracheal delivery of alloantigen plus anti-CD70, anti-CD134L, or anti-CD153 mAb, but not those given intratracheal delivery of alloantigen plus anti-CD137L mAb, rejected their graft acutely (MST 16, 14, 10, and 65 days, respectively). Adoptive transfer of splenocytes from mice pretreated with intratracheal delivery of alloantigen plus anti-CD70, CD134L, or CD153 mAb did not prolong survival of C57BL/10 cardiac grafts in naive secondary CBA recipients (MST 14, 11, and 11 days, respectively), whereas adoptive transfer of splenocytes from mice given intratracheal delivery of alloantigen plus anti-CD137L mAb did (MST 75 days).
Conclusion: The CD27/CD70, CD134/CD134L, and CD30/CD153 pathways are independently required for generation of regulatory cells in our model.