A novel cell-based assay for inhibitory anti-muscarinic type 3 receptor antibodies in primary Sjögren's syndrome

Isabell Bastian, Thomas Gordon, Michael Jackson

Research output: Contribution to journalArticlepeer-review

2 Citations (Scopus)


Inhibitory autoantibodies acting at the muscarinic acetylcholine receptor type 3 (M3R) are postulated to mediate autonomic dysfunction, including decreased salivary and lacrimal gland output and extra-glandular manifestations, in patients with primary Sjögren's syndrome. However, the contention that anti-M3R antibodies are pathogenic in patients remains untested, due to a lack of assays both sophisticated enough to detect inhibitory anti-M3R antibodies yet suitable for screening large patient cohorts. In the current study, we have established a cell-based bioassay of M3R activity, based on dual transfection of the M3R and a luciferase reporter gene. The bioassay is capable of capturing real-time agonist-mediated signalling of the M3R, which is inhibited specifically by patient IgG that have previously been demonstrated to have anti-M3R activity. The assay can be run in multi-well culture plates, and analysed using simple luminescence readers. As such, the new bioassay incorporating M3R-mediated luciferase transduction is the first assay adaptable to common diagnostic platforms that is capable of determining the presence in patient serum of functionally active anti-M3R autoantibodies. The new bioassay should prove useful for large cohort screening studies aiming to correlate the presence in patients of inhibitory anti-M3R antibodies with symptoms of both glandular and extra-glandular autonomic dysfunction.

Original languageEnglish
Pages (from-to)117-121
Number of pages5
JournalJournal of Immunological Methods
Publication statusPublished - 1 Dec 2015


  • Anti-M3R antibodies
  • Autoantibodies
  • Functional antibodies
  • Muscarinic receptors
  • Sjögren's syndrome


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