Published online before print August 3, 2009
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,1
* Division of Medical Sciences and
Department of Pathology, Harvard Medical School, Boston, Massachusetts, USA; and
Department of Cancer Immunology and AIDS, Dana-Farber Cancer Institute, Boston, Massachusetts, USA
1. Dana Farber Cancer Institute, Cancer Immunology and AIDS, 44 Binney St., Boston, MA 02115, USA. E-mail: shannon_turley{at}dfci.harvard.edu
Bone marrow-derived APCs are considered the predominant cell type involved in the induction and maintenance of T cell tolerance in vivo. In the periphery, cross-presentation of self-antigens by DCs, in particular, CD8
+ DCs, has been the most discussed mechanism underlying the induction of CD8+ T cell tolerance against self. However, nonhematopoietic APCs in the liver, skin, parenchymal tissues, and lymph nodes can also present self- and exogenous antigens to CD8+ T cells under steady-state conditions. Although far surpassed by their DC counterparts in their ability to stimulate T cell responses, these unconventional APCs have been shown to play a role in the induction, maintenance, and regulation of peripheral CD8+ T cell tolerance by a multitude of mechanisms. In this review, we will discuss the different nonhematopoietic cells that have been shown to present tissue-specific or exogenous antigens to naïve CD8+ T cells, thereby contributing to the regulation of T cell responses in the periphery.
Key Words: lymph nodes • stroma • parenchymal cell • nonhematopoietic cell
