La. Lee et al., SPECIFIC TOLERANCE ACROSS A DISCORDANT XENOGENEIC TRANSPLANTATION BARRIER, Proceedings of the National Academy of Sciences of the United Statesof America, 91(23), 1994, pp. 10864-10867
Successful induction of tolerance across disparate (discordant) specie
s barriers could overcome the organ shortage that presently limits cli
nical transplantation. We demonstrate here that xenogeneic swine thymi
c transplants can induce tolerance to swine antigens in mice, while po
sitively selecting functional host CD4(+) T cells. Immunologically nor
mal C57BL/10 mice were thymectomized and depleted of T and natural kil
ler cells; then they received transplants of fetal pig thymus and live
r fragments. Mature mouse CD4(+) T cells developed in the pig thymus g
rafts and migrated to the periphery. Swine grafts grew markedly and no
anti-pig IgG response was produced. Mixed lymphocyte reactions confir
med that the new T cells were functional and were tolerant to pig anti
gens.