PRIVILEGED STATUS OF THE SUBCUTANEOUS SITE FOR SKIN ALLOGRAFTS IN RATS

Evidence is presented that in rats the s.c. site can extend privilege to major histocompabitility complex (MHC)-incompatible (FI .times. DA)F1 .fwdarw. FI and MHC-compatible LEW .fwdarw. FI skin allografts, approximately doubling the median survival time of similar grafts transplanted orthotopically. Unlike graft dosage, gene dosage was an important variable in that grafts from (FI .times. DA)F1 donors significantly outlived those from DA strain donors. Prior splenectomy of the hosts did not prejudice the capacity of their s.c. sites to extend privilege. The hemagglutinin response incited by s.c. grafts was significantly delayed compared with that evoked by similar grafts transplanted orthotopically or i.p. This observation, coupled with the inability to demonstrate the passage of India ink to regional lymph nodes after its injection into the dermis of established s.c. grafts of syngenic skin, was consistent with the concept that poor endowment of the s.c. milieu with blood and lymph vessels is the principal factor underlying its hospitality to allografts.