Survival and Rejection of Second-Set Skin Allografts

Abstract

On the basis of their observations that a host develops a sensitivity directed specifically against further donations of an allograft from the first donor, Gibson and Medawar (1943) formulated the original hypothesis of acquired immunity. If a second graft from the same donor is applied, it is destroyed in an accelerated fashion, termed the “second-set phenomenon” by Medawar (1944, 1945). Whereas the primary graft of normal skin is generally rejected within 7–8 days after application, second-set grafts seldom survive beyond 5–6 days. Additional repeat-set allografts show no further shortening of the recipient’s rejection time, but are destroyed at the same rate as the secondset grafts (Lehrfeld, Taylor, and Converse 1955; Rapaport and Converse 1958) (see the section on The White Graft Reaction).