Autoantibodies against submandibular gland muscarinic cholinoceptor subtypes in primary Sjögren Syndrome

REINA SILVIA, STERIN-BORDA LEONOR, ORMAN BETINA, BORDA ENRI

EUROPEAN JOURNAL OF INFLAMMATION

BIOLIFE SAS

Lugar: Roma, Italia; Año: 2005 vol. 3 p. 135 - 141

1721-727X

Sjogren Sindrome (SS) is a chronic autoimmune disease characterized by parasympathetic exicrine gland dysfunction, Here, the involvement of submandibular gland muscarinic acetylcholine receptor (mAChR) M4 subtype is proposed as an IgG target together with M1 and M3 mAChR subtypes. The Kd values were total membranes 0.20 +/- 0.017 nM, acini membranes 0.33 +/- 0.023 nM and duct membranes 0.22 +/- 0.040 nM and Bmax values were total, 1038 +/- 24, acini, 1359 +/- 28 and ducts, 593 +/- 30. The rank order of Bmax was: acini>total>ducts, indicating that acini express the highest number of binding sites. The specific mAChR antagonist (4-DAMP [M3], tropicamide [M4], pirenzepine [M1]) and the corresponding synthetic peptides impaired IgG-mAChR subtype interactions. The specificity of these reactiosn was assessed by the corresponding affinity-purified anti peptide antobodies recognizing M4, M3 and ;1 mAChR. These data concerning autoantibodies contribute to explain the pathogenesis of SS and also represent a new clinical marker for SS diagnosis.