A novel lacrimal gland autoantigen in the NOD mouse model of Sjögren's syndrome.

Recent research has demonstrated a crucial role for autoantibodies in the pathogenesis of Sjögren's syndrome (SS)-like disease in the non-obese diabetic (NOD) mouse, but it remains to be determined which antibody species among all those present are directly related to the various aspects of pathology. To identify autoantigens in the NOD mouse system, we have taken the approach of using immunoglobulin (Ig)G purified from sera of NOD mice exhibiting SS-like symptoms to screen cDNA expression libraries derived from exocrine gland mRNA. Here we report the identification of a novel autoantigen, designated LGP10, expressed in lacrimal and submandibular glands. Autoantibodies to this protein are prominent in the sera of NOD mice starting at 11-12 weeks of age, but not in control nonautoimmune mice. LGP10 has no known function, but bears similarities to various other proteins produced by epithelia. Interestingly, all of these similar proteins have been linked to immunosuppression and/or steroid binding, both processes that could have a significant impact on pathological features of SS.