| Budget Amount *help |
¥2,200,000 (Direct Cost: ¥2,200,000)
Fiscal Year 1990: ¥900,000 (Direct Cost: ¥900,000)
Fiscal Year 1989: ¥500,000 (Direct Cost: ¥500,000)
Fiscal Year 1988: ¥800,000 (Direct Cost: ¥800,000)
|
|---|
| Research Abstract |
While tadpoles of the South African clawed frog, Xenopus laevis, are immunologically potent for allograft rejection and antibody formation, they never attack the newly appearing adult type self antigens during metamorphosis. This indicates, in turn, they become tolerant against adult type antigens dring this particular period. If tadpoles of the inbred J-strain individuals designated JJ (MHC haplotype jj) are grafted with semixenogeneic adult JB skin (X. laevis x X. borealis ; MHC jb) before or during metamorphosis, many of them tolerate it, while they never accept BB skin. The state of tolerance thus induced will be maintained beyond metamorphosis as revealed by the total acceptance of the second graft possessing the same MHC haplotypes. Because they still show the allograft rejecting capacity against third party donor skin, is evident that the tolerance is antigenically specific. If late thymectomy was operated on the tadpoles before or just after the tolerizing skin grafting, the tolerance induction always failed indicating that the presence of the thymus is prerequisite for this type of tolerance induction. The presence of the thymus is required for about 2 weeks from the skin frafting.
The inbreeding effort being continued along with the above mentioned project resulted in the formation of 7th generation of inbred Xenopus borealis. Skin graft made among siblings of 6th generation froglets indicated that the homozygous MHC are already shared among all siblings and some individuals (ca. 40%) showed perfect acceptance of sibling skin showing the homozygosity of not only MHC but also minor antigens among some siblings.
|
