allogene

Allogene refers to cells, tissues, organs, or organisms that originate from a donor of the same species but who is genetically different from the recipient. The term is commonly used in contrast to autologous sources (from the same individual) and syngeneic sources (genetically identical, such as from an identical twin or an inbred strain). The word allogene is rooted in Greek, with allos meaning "other" and genos meaning "origin" or "race," and is typically encountered in the form allogeneic.

In clinical practice, allogeneic transplants include hematopoietic stem cell transplants, organ transplants, and various tissue grafts. A central issue is immune compatibility; mismatches in human leukocyte antigens (HLA) can lead to graft rejection or graft-versus-host disease, requiring donor–recipient matching and often immunosuppressive therapy. The success and risks of allogeneic transplantation depend on factors such as degree of HLA matching, donor availability, and the recipient’s immune status.

In research and medicine, allogeneic materials are used to study immune responses, transplantation biology, and cell therapies. The term is widely used in biomedical literature, with allogeneic or allogeneic transplantation indicating non-self, donor-derived material from the same species. See also autologous transplantation, syngeneic transplantation, and xenogeneic transplantation.