Effects of muscarinic acetylcholine 3 receptor208-227 peptide immunization on autoimmune response in nonobese diabetic mice

Abstract

The second extracellular loop (LFWQYFVGKRTVPPGECFIQFLSEPTITFGTAI, aa 205-237) of muscarinic acetylcholine 3 receptor (M3R) has been reported to be an epitope for autoantibodies generated during certain autoimmune disorders, including Sjögren's syndrome (SS). Autoantibodies against M3R 228-237 have been shown to interfere with the function of M3R. However, few studies have been performed on the M3R205-227 peptide of the second extracellular loop. In the current study, we sought to investigate the effect of M3R208-227 peptide immunization on autoimmune response in NOD/LtJ mice. We synthesized the M3R208-227 peptide and immunized NOD/LtJ mice to investigate whether peptide-specific antibodies could be generated and whether immunization would lead to changes in autoimmune response in NOD/LtJ mice. Our results demonstrate that the secretions of Th-1, Th-2, and Th-17 cytokines are downregulated and lymphocytic infiltration is improved in the salivary glands and lacrimal glands following immunization with M3R 208-227 peptide in NOD/LtJ mice, suggesting that peptide immunotherapy using the M3R208-227 peptide may represent a potential therapeutic alternative. © 2013 Lin Yang et al.