Constitutive neuronal expression of the immune regulator, programmed death 1 (PD-1), identified during experimental autoimmune uveitis.

Citation:

Chen L, Pai V, Levinson R, Sharpe AH, Freeman GJ, Braun J, Gordon LK. Constitutive neuronal expression of the immune regulator, programmed death 1 (PD-1), identified during experimental autoimmune uveitis. Ocul Immunol Inflamm. 2009;17 (1) :47-55.

Date Published:

2009 Jan-Feb

Abstract:

PURPOSE: Programmed death-1 (PD-1) ligation downregulates active lymphocyte responses. The authors tested whether PD-1 or its ligands are expressed in the posterior segment during active intraocular inflammation. METHODS: Experimental autoimmune uveitis (EAU) was induced using interphotoreceptor retinoid-binding protein (IRBP 161-180). Ocular inflammation was evaluated by histology and expression of PD-1 ligand tested by immunohistochemistry. PD-1 expression was evaluated by immunohistochemistry, RT-PCR, and Western immunoblotting. RESULTS: Using immunohistochemistry, PD-1, but not its ligands, was constitutively expressed in retinal neurons of naive mouse retina. Both PD-1 and its ligands were observed, as expected, in sites of active inflammation. CONCLUSIONS: PD-1 and its ligands were expressed in sites of active inflammation, in accordance with many other models of inflammatory disease. Surprisingly, PD-1, not previously described outside the immune system, was constitutively expressed in retinal neurons, raising the possibility that PD-1 signaling may be important for neuronal function in the absence of an inflammatory insult.