Nature Medicine
6, 686 - 688 (2000)
doi:10.1038/76267
Immunologic 'ignorance' of vascularized organ transplants in the absence of secondary lymphoid tissueFadi G. Lakkis, Alexandr Arakelov, Bogumila T. Konieczny
& Yoshihiko Inoue
Renal Division, Department of Medicine, Emory University School of Medicine and Veterans Affairs Medical Center, 1670 Clairmont Road, Atlanta, Georgia 30033, USA
Correspondence should be addressed to Fadi G. Lakkis fglakki@emory.eduSecondary lymphoid organs (the spleen, lymph nodes and mucosal lymphoid tissues) provide the proper environment for antigen-presenting cells to interact with and activate naive T and B lymphocytes1. Although it is generally accepted that secondary lymphoid organs are essential for initiating immune responses to microbial antigens and to skin allografts2,
3,
4,
5,
6, the prevailing view has been that the immune response to primarily vascularized organ transplants such as hearts and kidneys does not require the presence of secondary lymphoid tissue. The assumption has been that the immune response to such organs is initiated in the graft itself when recipient lymphocytes encounter foreign histocompatibility antigens presented by the graft's endothelial cells7,
8,
9,
10,
11,
12,
13. In contrast to this view, we show here that cardiac allografts are accepted indefinitely in recipient mice that lack secondary lymphoid tissue, indicating that the alloimmune response to a vascularized organ transplant cannot be initiated in the graft itself. Moreover, we demonstrate that the permanent acceptance of these grafts is not due to tolerance but is because of immunologic 'ignorance'.
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