Sjögren’s syndrome (SjS) is an autoimmune disease characterized by symptoms of dry eye and dry mouth accompanied by lymphocytic infiltration of the lacrimal and salivary glands and the expression of autoantibodies to intracellular acinar proteins, including M3 muscarinic receptor. Recent work has demonstrated that the lacrimal acinar cells can express major histocompatability complex (MHC) class II molecules under certain conditions. One model for establishment of SjS suggests that the potential autoantigens may gain access and enter the endosomal/lysosomal pathway to bind MHC II molecules and initiate an autoimmune response.