Skip to Content
MilliporeSigma
  • MZB1 promotes the secretion of J-chain-containing dimeric IgA and is critical for the suppression of gut inflammation.

MZB1 promotes the secretion of J-chain-containing dimeric IgA and is critical for the suppression of gut inflammation.

Proceedings of the National Academy of Sciences of the United States of America (2019-05-28)
Ermeng Xiong, Yingqian Li, Qing Min, Chaoqun Cui, Jun Liu, Rongjian Hong, Nannan Lai, Ying Wang, Jiping Sun, Ryohtaroh Matsumoto, Daisuke Takahashi, Koji Hase, Reiko Shinkura, Takeshi Tsubata, Ji-Yang Wang
ABSTRACT

IgA is the most abundantly produced antibody in the body and plays a crucial role in gut homeostasis and mucosal immunity. IgA forms a dimer that covalently associates with the joining (J) chain, which is essential for IgA transport into the mucosa. Here, we demonstrate that the marginal zone B and B-1 cell-specific protein (MZB1) interacts with IgA through the α-heavy-chain tailpiece dependent on the penultimate cysteine residue and prevents the intracellular degradation of α-light-chain complexes. Moreover, MZB1 promotes J-chain binding to IgA and the secretion of dimeric IgA. MZB1-deficient mice are impaired in secreting large amounts of IgA into the gut in response to acute inflammation and develop severe colitis. Oral administration of a monoclonal IgA significantly ameliorated the colitis, accompanied by normalization of the gut microbiota composition. The present study identifies a molecular chaperone that promotes J-chain binding to IgA and reveals an important mechanism that controls the quantity, quality, and function of IgA.