Immune response to ocular antigens is unique in that it is selectively deficient in delayed type hypersensitivity (DTH) mediating Th1 effectors and complement fixing immunoglobulins, while non-complement fixing immunglobulins and cytotoxic T cells remain detectable. Such deviation from a conventional immune response is referred to as Anterior Chamber Associated Immune Deviation (ACAID). This immune response is known to contribute to the immune privilege status of the eye. Resident ocular antigen presenting cells (APCs) are endowed with the ability to induce this response in an antigen specific manner by migrating out to the recipient spleen and presenting antigen to the responders T cells in a manner that generates regulatory cells. These cells in turn are known to prevent DTH responses. The ACAID-inducing ability of ocular APCs is mainly attributed to their exposure to TGFbeta in the eye. Conventional APCs derived from non-ocular sources are also known to acquire such unique ACAID-inducing properties when exposed to TGFbeta. Understanding molecular mechanisms underlying this functional transformation in APCs offers potential to develop therapeutic strategies to prevent ocular inflammation as well as to generate regulatory APCs ex vivo to be used for various clinical applications that require regulation of an undesirable immune response. To this end we have attempted identification of genes that are selectively expressed in TGFbeta-treated APCs. Applying differential analysis of genes (RAP-PCR and Genechip Microarrays) to RNA isolated from untreated APCs and TGFbeta-treated APCs, we isolated several differentially expressed genes that can be relevant in ACAID-inducing properties of APCs. Such an approach has allowed us to select potentially significant genes that have been unsuspected, so far, to be relevant in ACAID-induction. To begin with, we have chosen genes based on their known properties and as they relate to existing information available regarding various aspects of ACAID and APCs involved in its induction as well as the unique ocular microenvironment. We now propose to analyze the participation of these gene products (thrombospondin, TNFR II and IkappaBetaalpha) and their role in ACAID induction by TGFbeta-treated APCs. First, significance of these molecules in development of various aspects of ACAID will be evaluated followed by analysis of individual mechanisms regulated by these gene products. By comparing the effects of these genes and assessing interrelated mechanisms we propose to test a possibility to effectively use TGFbeta-treated APCs to prevent experimental autoimmune uveitis (EAU) and skin allograft rejection.
Showing the most recent 10 out of 23 publications
