Format

Send to

Choose Destination
Arthritis Rheumatol. 2016 Mar;68(3):614-26. doi: 10.1002/art.39455.

Autoantibodies From Single Circulating Plasmablasts React With Citrullinated Antigens and Porphyromonas gingivalis in Rheumatoid Arthritis.

Author information

1
Qilu Hospital of Shandong University, Ji'nan, Shandong, China, and University of Nebraska Medical Center, Omaha.
2
University of Nebraska Medical Center, Omaha.
3
Veterans Affairs Nebraska-Western Iowa Health Care System, and University of Nebraska Medical Center, Omaha.
4
University of Nebraska Medical Center, Omaha, and University of Nebraska Medical Center, Lincoln.
5
Sichuan University, Chengdu, China, University of Nebraska Medical Center, Omaha, and The Eppley Institute for Research in Cancer and Allied Diseases, Omaha.
6
University of Nebraska Medical Center, and The Eppley Institute for Research in Cancer and Allied Diseases, Omaha.

Abstract

OBJECTIVE:

Anti-citrullinated protein antibodies (ACPAs) are highly specific for rheumatoid arthritis (RA). However, the molecular basis for ACPA production is still unclear. The purpose of this study was to determine if circulating plasmablasts from RA patients produce ACPAs and whether Porphyromonas gingivalis facilitates the generation of ACPAs.

METHODS:

Using a single-cell antibody cloning approach, we generated 217 and 110 monoclonal recombinant antibodies from circulating plasmablasts from 7 RA patients and 4 healthy controls, respectively. Antibody reactivity with citrullinated antigens was tested by a second-generation anti-cyclic citrullinated peptide (anti-CCP) kit and by enzyme-linked immunosorbent assays (ELISAs) against citrullinated human antigens. Antibody reactivity with P gingivalis was tested by ELISAs against outer membrane antigens (OMAs) and citrullinated enolase from P gingivalis.

RESULTS:

Approximately 19.5% of plasmablast-derived antibodies from anti-CCP-positive RA patients, but none from 1 anti-CCP-negative RA patient or the healthy controls, specifically recognized citrullinated antigens. The immunoglobulin genes encoding these ACPAs were highly mutated, with increased ratios of replacement mutations to silent mutations, suggesting the involvement of active antigen selection in ACPA generation. Interestingly, 63% of the ACPAs cross-reacted with OMAs and/or citrullinated enolase from P gingivalis. The reactivity of ACPAs against citrullinated proteins from P gingivalis was confirmed by immunoblotting and mass spectrometry. Furthermore, some germline-reverted ACPAs retained their reactivity with P gingivalis antigens but completely lost their reactivity with citrullinated human antigens.

CONCLUSION:

These results suggest that circulating plasmablasts in RA patients produce ACPAs and that this process may be facilitated by anti-P gingivalis immune responses.

PMID:
26474325
PMCID:
PMC5770231
DOI:
10.1002/art.39455
[Indexed for MEDLINE]
Free PMC Article

Supplemental Content

Full text links

Icon for Wiley Icon for PubMed Central
Loading ...
Support Center