Progress in experimental intestinal transplantation in small animal models

The unique immune response after small bowel transplantation (SBT) has been the subject of extensive research using small animal models in rats and mice. These animals are inexpensive, for most societies ethically acceptable and the existence of inbred strains allows for reproducibility and defined immunobiological conditions. The basic immunological reactions, such as graft-versus-host-reactions (GVHR), host-versus-graft-reactions (HVGR), a combination of both reactions, chronic rejection and tolerance have been described. Almost all immunosuppressive agents of proven or potential clinical relevance have been tested for their efficacy in small bowel transplantation. All techniques which are applied to intestinal transplantation in humans including multiorgan transplantation, can also be performed in rats. Intestinal transplantation in mice is methodically restricted to heterotopic transplantation. The mouse however, offers several advantages compared to the rat model. A large number of congenic and knockout strains is available as well as many analytical tools. In the future, intriguing new insights into the unique immunological mechanisms of allograft rejection will be discovered using murine models.