>Contents>Ocular Immune Privilege
Our understanding of the anterior chamber of the eye as an immune-privileged site is based on solid experimental evidence and is supported by considerable clinical experience. Allografts prepared from a variety of different tissues (skin, thyroid, islets of Langerhans, cornea, retina) experience prolonged, even indefinite survival when placed in the anterior chamber. Two types of experimental grafts make this point dramatically: (1) Allogeneic tumor cells that are summarily rejected when placed subcutaneously form progressively growing tumors when injected into the anterior chamber of eyes of immunologically normal mice and rats. (2) Corneal tissue obtained from the eye of one individual enjoys extended survival when grafted orthotopically to the anterior surface of the eye of a normal individual, even though corneal tissue grafted heterotopically to the skin surface is rejected promptly. The experience of corneal surgeons makes the same point. The most common solid tissue transplantion performed in humans is corneal transplantation, and these transplants enjoy the highest rate of success compared to all other types of solid tissue grafts. This is true even though the immunosuppression used to control rejection is applied topically, rather than systemically.
Over the past 30 years, investigators have learned much about the physiologic processes responsible for immune privilege in the eye: special architectural features of the anterior chamber, and unique immunomodulatory molecules present in the ocular fluids and expressed on ocular parenchymal cells. Together they govern and modify the manner in which antigenic material placed in the anterior chamber is recognized by cells and molecules of the systemic immune apparatus. In addition, these processes alter the ways in which immune effector molecules and cells respond to foreign and antigenic material that is present within the eye. The net effect of these forces is to limit the intraocular development of inflammation.
The Eye's Dilemma
Immune Privilege
Anterior Chamber of the Eye as an Immune- Privileged Site
Inflammation of Relation to Innate and Adaptive Immune Responses
Ocular Factors That Promote Immune Tolerance of Eye-Derived Antigens
Factors That Modify Expression of Ocular Adaptive Immunity
Innate Immune Privilege in the Eye
Factors That Modify Expression of Innate Ocular Immunity
Clinical Meaning of Ocular Immune Privilege
Selected Reading
Biography
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