Studies on the Nature of Immunity to Homologous Grafted Skin, With Special Reference to the Use of Pure Epidermal Grafts

Abstract

1. Homografts of pure epidermis, i.e. of skin freed from all dermal elements, survive their orthotopic transplantation between unrelated rabbits for 10-15 days. They elicit and succumb to a transplantation immunity reaction just as ordinary skin homografts do. 2. The distinctive sequence of histological changes that take place in the dermis of a skin homograft during the course of its breakdown take place in the host's own young fibrous tissue when this forms the bed underlying pure epidermal homografts. 3. Although the breakdown of pure epidermal homografts is accelerated when they are transplanted to specifically immunized recipients, they normally survive for from 4-6 days. It is inferred that the serum and tissue exudates present in the bed to which such grafts are transplanted have no immediate inimical effect on the susceptible Malpighian cells when these are intimately exposed to them. 4. The possible application of pure epidermal grafts, and more particularly of dissociated epidermal cells, has been investigated in attempts to demonstrate a specific toxic action against a donor's cells of the blood, serum, and other derivatives of specifically immunized animals. After treatment in vitro, the ‘vitality’ of the epidermal grafts or cells was tested by transplanting them back to the animal from which they originated. 5. It was found that epidermal melanocytes of guinea-pig's skin are unaffected by prolonged treatment in vitro with ‘immune’ blood and serum, with or without the addition of lymphocytes or spleen cells. 6. The capacity of dissociated Malpighian cells in the rabbit to give rise to epithelium after grafting was completely or partially inhibited by treating them in vitro with excess immune serum for 22 hr. or longer at either 5° C. or 37° C. 7. It is suggested that this effect indicates the presence of a protective iso-antibody in the serum of rabbits which have reacted against skin homografts. The probable role of this antibody in the breakdown of skin homografts in vivo is discussed.