Figure 7. IDO associated regulation of donor-reactive immune responses.
Splenocytes from renal allograft acceptors early (day 60) or late (day 150) post-transplant were combined with alloantigen alone or alloantigen + polyclonal antibodies to IDO. These combinations were injected into pinnae of naïve C57BL/6 mice for trans-vivo DTH measurements. Early allograft acceptors showed no evidence of IDO regulation (*p=0.76), but late renal allograft acceptors demonstrated prominent donor-reactive DTH regulation by IDO (**p=0.005). Anti-IDO antibody and splenocytes without donor antigen showed DTH responses consistent with controls (not shown). DTH responses were measured after 24 hours as change in ear thickness (mean ± SD x 10-4 inches).