ENHANCED CD4 RECONSTITUTION BY GRAFTING NEONATAL PORCINE TISSUE IN ALTERNATIVE LOCATIONS IS ASSOCIATED WITH DONOR-SPECIFIC TOLERANCE AND SUPPRESSION OF PREEXISTING XENOREACTIVE T CELLS1

Grafting neonatal porcine thymus into either the mediastinum or mesentery provides earlier and more efficient reconstitution of the CD4 compartment than does grafting under the kidney capsule. Good CD4 reconstitution was associated with optimal donor-specific skin graft tolerance and avoidance of the anti-donor xenoantibody responses observed in mice with poor CD4 reconstitution. These results also suggest that there is a suppressive component to the porcine xenograft tolerance induced with this approach.