Role of resident corneal leukocytes and draining cervical lymph nodes in corneal allograft rejection.

摘要

We review recently published experimental evidence on corneal transplant immunology involving cornea and draining cervical lymph nodes (CLNs) in the mouse. In the cornea, major histocompatibility complex (MHC) class II- dendritic cells (DCs) are present in the corneal epithelium. These DCs can express MHC class II antigen in vivo and in vitro. In the corneal stroma, there are many leukocytes of monocyte or macrophage lineage. Normal cornea has been reported to contain a significant number of bone marrow-derived resident cells, which may be able to act as antigen-presenting cells. Allograft rejection does not occur if draining CLNs are removed before corneal transplantation, indicative of an essential role of CLNs in promoting corneal allorejection. Moreover, donor cornea-derived DCs were detected in host draining CLNs in a mouse corneal transplantation model. These findings provide direct evidence that MHC class II- bone marrow-derived antigen-presenting leukocytes exist in the part of cornea used for transplantation and that direct allorecognition of antigen is, at least in part, relevant to the occurrence of corneal allograft rejection in which draining CLNs play a central role.