Cell-Mediated Cytotoxicity During Rejection and Enhancement of Allogeneic Skin Grafts in Rats

Abstract

Measurement of cell-mediated cytotoxicity (CMC) 1 directed to cell surface antigens has been facilitated by the elaboration of a relatively simple reproducible test in which ~lCr is released from labeled target cells (1-5). Other investigators have examined certain facets of the test (6-18) and have applied the technique to studies of tumor allograft systems (3-5, 16, 19, 20) and soluble antigens bound to the surface membrane of target cells (18,(21)(22)(23)(24)(25)(26).The purpose of this study was to detect the appearance of cytotoxic lymphocytes (CL) in spleens and draining lymph nodes of rats grafted with allogeneic skin b y means of a modified 51Cr release assay and to quantitate CMC during rejection and prolonged survival of allografts induced by enhancing antibodies. With 5~Cr-labeled embryonic fibroblasts (EFB) as target cells derived from donor strain rats that were the source of immunizing skin grafts, and with cytotoxic lymphoid cells from sensitized recipients, the level of cellular immunity could be determined in recipients of skin allografts. Materials and MethodsAnlmals.--150-2OO-g adult and neonatal Lewis (Le) rats were both used as skin-graft recipients and donors of aggressor cells for assays of CMC in vitro. Brown-Norway (BN) rats were a source of skin allografts and of target cells for CMC assays. Both inbred strains were obtained from our own breeding colony or from a commercial breeder (Simonsen Laboratories, Gilroy, Calif.). BN skin grafts, 1.5 cm on edge, were applied to the nuchal region of 7-8-day-old Le neonates or to the axillae of adult Le rats. The latter were either normal, injected intraperitoneally with 5 mg of cyclophosphamide 2 daily beginning 4 days before grafting, or neonatally thymectomized 2448 hr after birth and used 100 or more days later. Completeness of * This is publication No. 573 from

Histological criteria for immunological rejection of mouse skin homografts

“…The role of activated lymphocytes in graft rejection has been repeatedly stressed. Numerous observations showed that lymphocyte activation is an important step in the sensitisation of the host to the homograft (Binet and Mathe, 1962;Hall, 1967;Hersh et al, 1971;Hamburger, 1972;Peter and Feldman, 1972). Some experimental evidence indicates, however, that the effector cells are not lymphocytes or at least not the presently known lymphocyte types.…”

Daily Monitoring of the Immune Response to Various Allografts in Rats

“…To be a valid monitor of an immune response, the proliferative response must be related to the subsequent fate of the graft. The generation of cytotoxic lymphocytes has been studied as a parameter of the immune response, and the relationship between a cytotoxic lymphocyte response and subsequent rejection is well established (Mullen et al 1972, Peter & Feldman 1972, Biesecker 1973. Unfortunately, the detection of cytotoxic lymphocytes is a relatively insensitive procedure and the quantities of lymphoid cells would not be obtainable daily from each animal.…”