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Immune responses to Ro60 and its peptides in mice. I. The nature of the immunogen and endogenous autoantigen determine the specificities of the induced autoantibodies.

Deshmukh US, Lewis JE, Gaskin F, Kannapell CC, Waters ST, Lou YH, Tung KS, Fu SM - J. Exp. Med. (1999)

Bottom Line: With human Ro60316-335 as the immunogen, additional autoantibodies reactive with the Golgi complex were found.These results show that both the nature of the immunogen and the immunogenicity of the related endogenous antigen are important in determining the specificities of the autoantibodies generated.They have significant implications for proposed mechanisms on the generation of complex patterns of autoantibodies to a diverse group of autoantigens in SLE patients.

View Article: PubMed Central - PubMed

Affiliation: Division of Rheumatology, Department of Internal Medicine, University of Virginia School of Medicine, Charlottesville, VA 22908, USA.

ABSTRACT
Anti-Ro60 autoantibodies are found in a variety of autoimmune disorders including systemic lupus erythematosus (SLE), Sjögren's syndrome, primary biliary cirrhosis, and active hepatitis. They are the most prevalent autoantibodies in normal individuals and in asymptomatic mothers of infants afflicted with neonatal lupus. In the present study, immune responses to recombinant human Ro60 (rhRo60) and recombinant mouse Ro60 (rmRo60) and selected Ro60 peptides in non-SLE-prone mice were investigated. Multiple T and B cell epitopes were identified in Ro60. Immunizations with either xenogeneic or autologous Ro60 induced autoantibodies to a diverse group of autoantigens. In addition to La and Ro52, proteins in the small nuclear ribonucleoprotein (snRNP) particles such as SmA, SmB, SmD, and 70-kD U1-RNP were unexpectedly identified as targeted antigens. In the studies involving synthetic Ro60 peptides, both human and mouse Ro60316-335 peptides, which differ in three amino acids, were found to contain dominant cross-reactive T cell determinants. Immunizations with these peptides induced autoantibodies to Ro60, La, SmD, and 70-kD U1-RNP without autoantibodies to Ro52, SmA, or SmB. With human Ro60316-335 as the immunogen, additional autoantibodies reactive with the Golgi complex were found. In contrast to the immunodominance of both human and mouse Ro60316-335 peptides, the T cell determinant in human Ro60441-465 was dominant, whereas that in the mouse peptide was cryptic. Immunization with human Ro60441-465 induced primarily anti-peptide Abs. Mouse Ro60441-465 failed to induce an antibody response. These results show that both the nature of the immunogen and the immunogenicity of the related endogenous antigen are important in determining the specificities of the autoantibodies generated. They have significant implications for proposed mechanisms on the generation of complex patterns of autoantibodies to a diverse group of autoantigens in SLE patients.

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Intramolecular diversification of antibody responses against  mRo60 following immunization with synthetic peptides. Pooled sera  from mice immunized either with hRo60316–335 peptide (A), or  hRo60441–465 peptide (B) were absorbed with their respective immunogens and peptide JS7A. Reactivity of unabsorbed and absorbed sera with  peptides and rmRo60 was determined in ELISA. Results are expressed as  mean duplicate OD490nm. Open bars denote unabsorbed pooled sera.  Cross bars denote pooled sera, absorbed with peptide JS7A. The hatched  bars denote pooled sera absorbed with hRo60316–335 in (A) and with  hRo60441–461 in (B).
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Figure 12: Intramolecular diversification of antibody responses against mRo60 following immunization with synthetic peptides. Pooled sera from mice immunized either with hRo60316–335 peptide (A), or hRo60441–465 peptide (B) were absorbed with their respective immunogens and peptide JS7A. Reactivity of unabsorbed and absorbed sera with peptides and rmRo60 was determined in ELISA. Results are expressed as mean duplicate OD490nm. Open bars denote unabsorbed pooled sera. Cross bars denote pooled sera, absorbed with peptide JS7A. The hatched bars denote pooled sera absorbed with hRo60316–335 in (A) and with hRo60441–461 in (B).

Mentions: Antibodies reactive to mRo60 epitopes not related to peptide hRo60316–335 were generated in mice immunized with the peptide (Fig. 12). Sera were absorbed with the immunogen to deplete them of antipeptide antibodies. These sera still recognized rmRo60 in ELISA, indicative of intramolecular epitope spreading (Fig. 12 A). Absorption of sera with a control peptide JS7A had little effect on the reactivity of sera, either to the peptide or to rmRo60 (Fig. 12 A). Results presented in Figs. 8–12 were representative of three experiments.


Immune responses to Ro60 and its peptides in mice. I. The nature of the immunogen and endogenous autoantigen determine the specificities of the induced autoantibodies.

Deshmukh US, Lewis JE, Gaskin F, Kannapell CC, Waters ST, Lou YH, Tung KS, Fu SM - J. Exp. Med. (1999)

Intramolecular diversification of antibody responses against  mRo60 following immunization with synthetic peptides. Pooled sera  from mice immunized either with hRo60316–335 peptide (A), or  hRo60441–465 peptide (B) were absorbed with their respective immunogens and peptide JS7A. Reactivity of unabsorbed and absorbed sera with  peptides and rmRo60 was determined in ELISA. Results are expressed as  mean duplicate OD490nm. Open bars denote unabsorbed pooled sera.  Cross bars denote pooled sera, absorbed with peptide JS7A. The hatched  bars denote pooled sera absorbed with hRo60316–335 in (A) and with  hRo60441–461 in (B).
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC2192918&req=5

Figure 12: Intramolecular diversification of antibody responses against mRo60 following immunization with synthetic peptides. Pooled sera from mice immunized either with hRo60316–335 peptide (A), or hRo60441–465 peptide (B) were absorbed with their respective immunogens and peptide JS7A. Reactivity of unabsorbed and absorbed sera with peptides and rmRo60 was determined in ELISA. Results are expressed as mean duplicate OD490nm. Open bars denote unabsorbed pooled sera. Cross bars denote pooled sera, absorbed with peptide JS7A. The hatched bars denote pooled sera absorbed with hRo60316–335 in (A) and with hRo60441–461 in (B).
Mentions: Antibodies reactive to mRo60 epitopes not related to peptide hRo60316–335 were generated in mice immunized with the peptide (Fig. 12). Sera were absorbed with the immunogen to deplete them of antipeptide antibodies. These sera still recognized rmRo60 in ELISA, indicative of intramolecular epitope spreading (Fig. 12 A). Absorption of sera with a control peptide JS7A had little effect on the reactivity of sera, either to the peptide or to rmRo60 (Fig. 12 A). Results presented in Figs. 8–12 were representative of three experiments.

Bottom Line: With human Ro60316-335 as the immunogen, additional autoantibodies reactive with the Golgi complex were found.These results show that both the nature of the immunogen and the immunogenicity of the related endogenous antigen are important in determining the specificities of the autoantibodies generated.They have significant implications for proposed mechanisms on the generation of complex patterns of autoantibodies to a diverse group of autoantigens in SLE patients.

View Article: PubMed Central - PubMed

Affiliation: Division of Rheumatology, Department of Internal Medicine, University of Virginia School of Medicine, Charlottesville, VA 22908, USA.

ABSTRACT
Anti-Ro60 autoantibodies are found in a variety of autoimmune disorders including systemic lupus erythematosus (SLE), Sjögren's syndrome, primary biliary cirrhosis, and active hepatitis. They are the most prevalent autoantibodies in normal individuals and in asymptomatic mothers of infants afflicted with neonatal lupus. In the present study, immune responses to recombinant human Ro60 (rhRo60) and recombinant mouse Ro60 (rmRo60) and selected Ro60 peptides in non-SLE-prone mice were investigated. Multiple T and B cell epitopes were identified in Ro60. Immunizations with either xenogeneic or autologous Ro60 induced autoantibodies to a diverse group of autoantigens. In addition to La and Ro52, proteins in the small nuclear ribonucleoprotein (snRNP) particles such as SmA, SmB, SmD, and 70-kD U1-RNP were unexpectedly identified as targeted antigens. In the studies involving synthetic Ro60 peptides, both human and mouse Ro60316-335 peptides, which differ in three amino acids, were found to contain dominant cross-reactive T cell determinants. Immunizations with these peptides induced autoantibodies to Ro60, La, SmD, and 70-kD U1-RNP without autoantibodies to Ro52, SmA, or SmB. With human Ro60316-335 as the immunogen, additional autoantibodies reactive with the Golgi complex were found. In contrast to the immunodominance of both human and mouse Ro60316-335 peptides, the T cell determinant in human Ro60441-465 was dominant, whereas that in the mouse peptide was cryptic. Immunization with human Ro60441-465 induced primarily anti-peptide Abs. Mouse Ro60441-465 failed to induce an antibody response. These results show that both the nature of the immunogen and the immunogenicity of the related endogenous antigen are important in determining the specificities of the autoantibodies generated. They have significant implications for proposed mechanisms on the generation of complex patterns of autoantibodies to a diverse group of autoantigens in SLE patients.

Show MeSH
Related in: MedlinePlus