Journal
HEPATOLOGY
Volume 39, Issue 5, Pages 1415-1422Publisher
WILEY
DOI: 10.1002/hep.20175
Keywords
-
Categories
Funding
- NIDDK NIH HHS [DK39588, K08 DK059653] Funding Source: Medline
Ask authors/readers for more resources
Anti-mitochondrial antibodies (AMAs) have long been recognized as a serological hallmark of primary biliary cirrhosis (PBC). Although high titers of immunoglobutin (Ig)A AMAs are found in bile, saliva, and urine of patients, a pathogenic role for this antibody has remained elusive. Functional studies of this IgA in general have been impeded by low quantities of antibody and the inability to recover antigen-specific IgA in dimeric form. Using a newly defined synthetic group A. Streptococcus derived peptide, we purified large quantities of dimeric and monomeric IgA from patient sera. The purified IgA was incubated with Madine-Darby canine kidney (MDCK) cells transfected with the human polymeric Ig receptor (pIgR) and the cells studied by flow cytometric analysis for binding of carboxyfluorescein conjugated VAD-fmk peptide to activated caspase enzymes. A total of 87% of PBC patients that were anti-PDC-E2 positive had serum IgA that increased caspase activation in MDCK-pIgR+ cells compared to serum-derived IgA from controls with a maximum reaction 48 hours after addition of IgA. The titer of anti-PDC-E2 IgA among the PBC patients strongly correlated with caspase activation (cc = 0.88). Pre-absorption of the IgA using recombinant 2-oxo-acid dehydrogenase complex significantly diminished this activation. IgG from the same PBC patients did not induce caspase activation. These data suggest that during transcytosis through pIgR-positive cells, exposure to PDC-E2-specific dimeric IgA results in the initiation of caspase activation. In conclusion, we propose that due to an even greater concentration of dimeric IgA in biliary and mucosal secretions, constant transcytosis would render the exposed cells more susceptible to apoptosis resulting in subsequent bile duct damage.
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available