HoHsieh A, Wang CM, Wu YJJ, Chen A, Chang MI, Chen JY. B cell epitope of human cytomegalovirus phosphoprotein 65 (HCMV pp65) induced anti-dsDNA antibody in BALB/c mice.
Arthritis Res Ther 2017;
19:65. [PMID:
28320458 PMCID:
PMC5359867 DOI:
10.1186/s13075-017-1268-2]
[Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2016] [Accepted: 02/16/2017] [Indexed: 11/10/2022] Open
Abstract
Background
HCMV phosphoprotein 65 (HCMVpp65) is a putative immunogen that acts as an accelerator, inducing autoantibody and exacerbating autoimmune response in susceptible animals. The immunity to pp65336-439 instigates autoimmunity, suggesting that pp65336-439 contains crucial B cell epitope(s) for the development of nephritis. This study narrowed down the target epitope to pp65422-439 for immunization of BALB/c mice and mapping of B cell epitope.
Methods
The target epitope pp65422-439 reactivity and B cell epitope mapping was examined in serum from pp65422-439-immunized mice and patients with systemic lupus erythematosus (SLE). Kidney tissue from immunized mice was examined for signs of immune complex nephritis.
Results
Anti-pp65422-439 antibody in serum either from patients with SLE or from pp65422-439-immunized mice exhibited cross-reactivity to several nuclear components such as double-stranded DNA (dsDNA). Moreover, the pp65422-439-immunized mice developed initial signs of glomerulonephritis such as deposition of immunoglobulin G/M (IgG/IgM) and third complement component (C3). With B cell epitope mapping by pp65422-439-derived decapeptides, one dominant epitope, pp65428-437, was identified in serum from pp65422-439-immunized mice and patients with SLE with anti-pp65422-439 antibody. Epitope spreading from pp65428-437 to pp65430-439 was found in pp65422-439-immunized mice in which we generated monoclonal antibodies to pp65425-434 and pp65430-439. However, dsDNA positive reactivity was exclusively observed in Crithidia luciliae stains with pp65430-439-reactive monoclonal antibody. Additionally, we observed the amelioration of autoimmunity following the elevation of IgM targeting pp65428-437.
Conclusions
Our data suggest that pp65428-437 may be an autoimmune or lupus-prone B cell epitope and may catalyze further epitope spreading for inducing autoantibodies in lupus-susceptible individuals.
Electronic supplementary material
The online version of this article (doi:10.1186/s13075-017-1268-2) contains supplementary material, which is available to authorized users.
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