Systemic lupus erythematosus (SLE) is a common multisystem autoimmune disease that is estimated to affect more than 500,000 Americans. Our goal is to gain a better understanding of the mechanisms that normally prevent expression of the self-reactive antibodies that cause the disease as well as to better understand where and how these mechanisms fail. Research into fundamental causes of disease in humans is often impossible due to ethical considerations. Decades of medical research attest to the usefulness of mouse models as a means to identify root causes as well as new avenues for treatment and prevention. The presence of the sle1, sle2, and/or sle3/5 NZM2410 lupus loci in C57BL/6 promotes development of an autoantibody driven disorder that shares many of the features of human SLE. It is our hypothesis that failure to properly regulate one specific part of the antibody, CDR-H3, in susceptible individuals facilitates production of anti-DNA antibodies and triggers disease. CDR-H3 is important because it lies at the very center of the antigen binding site. CDR-H3 is created de novo by VDJ joining. We propose that the sequence of the DH has a dominant effect on CDR-H3 content and that a primary mechanism normally constraining CDR-H3 is conservation of DH sequence by reading frame. We propose that autoimmunity results from failure to regulate use of the amino acids that can be found in disfavored reading frames. These amino acids can also be introduced by N addition or somatic mutation. We hypothesize that sle1, sle2, and sle3/5 genes adversely affect regulation of B cell and repertoire development by permitting increased survival of B cells bearing disfavored CDR-H3. To test these hypotheses we will breed three different DH alleles, each limited to a single DH gene segment, into the C57BL/6 genome. The first DH allele will substitute arginine and other positively charged amino acids from inverted reading frame 1 for the tyrosine and glycine that are normally encoded by the preferred reading frame 1 by deletion. The second will contain a single, normal DH as a control for the loss of the rest of the DH locus. The third will control for the loss of tyrosine and glycine content by substituting codons from hydrophobic reading frame 2. If our hypotheses are correct, enrichment for arginine in DH reading frame 1 will enhance expression of disfavored CDR-H3 sequence. This heightened expression will exceed the threshold for normal control of CDR-H3 content, accelerating expression of self-reactive antibodies, including anti-DNA. In the presence of sle1, sle2, and sle3/5, mice containing altered DH alleles will display altered patterns of B cell and repertoire development, evidence altered immune responses to antigen, demonstrate enhanced expression of IgG anti-dsDNA antibodies, and lead to accelerated expression of autoimmune disease. ? ? ? ?

Agency
National Institute of Health (NIH)
Institute
National Institute of Allergy and Infectious Diseases (NIAID)
Type
Research Project (R01)
Project #
5R01AI048115-08
Application #
7470572
Study Section
Special Emphasis Panel (ZRG1-HAI-K (08))
Program Officer
Johnson, David R
Project Start
2000-09-01
Project End
2011-06-30
Budget Start
2008-07-01
Budget End
2009-06-30
Support Year
8
Fiscal Year
2008
Total Cost
$311,841
Indirect Cost
Name
University of Alabama Birmingham
Department
Internal Medicine/Medicine
Type
Schools of Medicine
DUNS #
063690705
City
Birmingham
State
AL
Country
United States
Zip Code
35294
Khass, Mohamed; Schelonka, Robert L; Liu, Cun Ren et al. (2017) Alterations in B cell development, CDR-H3 repertoire and dsDNA-binding antibody production among C57BL/6 ?D-iD mice congenic for the lupus susceptibility loci sle1, sle2 or sle3. Autoimmunity 50:42-51
Wang, Yuge; Kapoor, Pratibha; Parks, Robert et al. (2016) HIV-1 gp140 epitope recognition is influenced by immunoglobulin DH gene segment sequence. Immunogenetics 68:145-55
Khass, Mohamed; Blackburn, Tessa; Burrows, Peter D et al. (2016) VpreB serves as an invariant surrogate antigen for selecting immunoglobulin antigen-binding sites. Sci Immunol 1:aaf6628
Khass, Mohamed; Blackburn, Tessa; Burrows, Peter D et al. (2016) VpreB serves as an invariant surrogate antigen for selecting immunoglobulin antigen-binding sites. Sci Immunol 1:
Silva-Sanchez, Aaron; Liu, Cun Ren; Vale, Andre M et al. (2015) Violation of an evolutionarily conserved immunoglobulin diversity gene sequence preference promotes production of dsDNA-specific IgG antibodies. PLoS One 10:e0118171
Trad, Ahmad; Tanasa, Radu Iulian; Lange, Hans et al. (2014) Clonal Progression during the T Cell-Dependent B Cell Antibody Response Depends on the Immunoglobulin DH Gene Segment Repertoire. Front Immunol 5:385
Vale, Andre M; Kapoor, Pratibha; Skibinski, Greg A et al. (2013) The link between antibodies to OxLDL and natural protection against pneumococci depends on D(H) gene conservation. J Exp Med 210:875-90
Khass, Mohamed; Buckley, Kevin; Kapoor, Pratibha et al. (2013) Recirculating bone marrow B cells in C57BL/6 mice are more tolerant of highly hydrophobic and highly charged CDR-H3s than those in BALB/c mice. Eur J Immunol 43:629-40
Westerink, M A Julie; Schroeder Jr, Harry W; Nahm, Moon H (2012) Immune Responses to pneumococcal vaccines in children and adults: Rationale for age-specific vaccination. Aging Dis 3:51-67
Lange, Hans; Hecht, Oliver; Zemlin, Michael et al. (2012) Immunoglobulin class switching appears to be regulated by B-cell antigen receptor-specific T-cell action. Eur J Immunol 42:1016-29

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