Which of the following statements characterize the biology of allotransplantation?

A. The rejection response is systemic.

B. The rejection response is learned.

D. Allotransplantation evokes a cellular immune response.

E. Allotransplantation evokes a humoral immune response.

DISCUSSION: Medawar and Gibson elucidated some of the basic principles of transplantation biology. Rejection of a second skin graft from the donor of a first graft is very much hastened, indicating that the response is learned and that the second response evokes “memory.” The second graft is rejected rapidly, regardless of its location, indicating that the response is systemic. The major immune reaction causing rejection of a first graft is a cellular immune response; however, the recipient exposed to allogeneic cells develops antibodies against alloantigens, indicating that a humoral response has also occurred.