Antibodies to a variety of cellular antigens, mostly nuclear in origin, have been detected in sera from mice and humans with systemic lupus erythematosus. There is compelling evidence that these autoantibodies, particularly autoantibody to DNA, are responsible at least in part for the pathological manifestations of lupus. The immunological basis for the generation of anti-DNA autoantibody in mice and humans has been difficult to elucidate. Previous attempts to stimulate antibody with the same specificity for binding to DNA as anti-DNA antibody in lupus have been unsuccessful. This fact coupled with the presence of a generalized abnormality in lymphoid cell development in mouse models for lupus has led to the proposal that lupus autoantibodies arise by antigen independent, polyclonal B cell activation. However, recent results from our molecular analyses of the structure and ontogeny of autoimmune anti-DNA antibodies have indicated that autoimmunity to DNA is both initiated and sustained as a clonally selected, specific immune response to DNA or DNA complexes. The secondary-immune characteristics of autoimmune anti-DNA antibody implicates the participation of antigen-specific helper T cells in the generation of this autoantibody, and experimental data support this hypothesis. However, little is known about the specificity and function of such T cells. We have recently established an experimental immunization model for the induction of antibody to DNA in mice not genetically predisposed to autoimmune disease. The immunogen used in this experimental system is DNA in a complex with a DNA-binding peptide. The induced anti- DNA antibody has structural and specificity characteristics identical to those of autoimmune anti-DNA antibody in lupus. Moreover, mice producing this antibody develop symptoms of early stage lupus-nephritis. The research proposed in this application will exploit the new experimental immunization system to generate T cell clones and hybrids specific for DNA-binding peptides. T cell clones and hybrids will be generated from normal, nonautoimmune-prone and autoimmune-prone mice immunized with DNA-peptide complexes. These clones and hybrids will then be used to determine the specificity and function of helper T cells that can induce in vitro anti-DNA antibody production when stimulated with specific DNA-peptide. In particular these experiments will determine whether the MHC-restricted T cell epitope for such T cells is formed by the peptide alone or a combination of DNA and peptide. The experiments will also determine how changes in the amino acid sequence of specific peptides affect their recognition by specific T cells. T-cell receptor variable-region structures from T cells specific for different peptide- or DNA-peptide complexes will be compared with T-cell receptor variable- region structures from autoimmune T cells that stimulate in vitro anti-DNA antibody production.

Agency
National Institute of Health (NIH)
Institute
National Institute of Arthritis and Musculoskeletal and Skin Diseases (NIAMS)
Type
Research Project (R01)
Project #
5R01AR042519-04
Application #
2006348
Study Section
Arthritis and Musculoskeletal and Skin Diseases Special Grants Review Committee (AMS)
Project Start
1993-12-10
Project End
1998-11-30
Budget Start
1996-12-01
Budget End
1998-11-30
Support Year
4
Fiscal Year
1997
Total Cost
Indirect Cost
Name
University of Tennessee Health Science Center
Department
Microbiology/Immun/Virology
Type
Schools of Medicine
DUNS #
941884009
City
Memphis
State
TN
Country
United States
Zip Code
38163
Krishnan, M R; Marion, T N (1998) Comparison of the frequencies of arginines in heavy chain CDR3 of antibodies expressed in the primary B-cell repertoires of autoimmune-prone and normal mice. Scand J Immunol 48:223-32
Ash-Lerner, A; Ginsberg-Strauss, M; Pewzner-Jung, Y et al. (1997) Expression of an anti-DNA-associated VH gene in immunized and autoimmune mice. J Immunol 159:1508-19
Wang, M; Desai, D; Marion, T N (1997) T cells specific for DNA-binding peptides. Lupus 6:349-50
Marion, T N; Krishnan, M R; Desai, D D et al. (1997) Monoclonal anti-DNA antibodies: structure, specificity, and biology. Methods 11:3-11
Krishnan, M R; Jou, N T; Marion, T N (1996) Correlation between the amino acid position of arginine in VH-CDR3 and specificity for native DNA among autoimmune antibodies. J Immunol 157:2430-9