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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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Immune response to rhRo60 in SJL/J (circles), A/J (squares),  and BALB/c (triangles) mice immunized with rhRo60. T cell responses  were studied in LNC proliferative assays (A) and antibody responses were  determined by ELISA (B). The LNC proliferative responses are expressed  as mean triplicate ΔCPM. In A, results are shown for mice immunized  with rhRo60 (open symbols) and with CFA (filled symbols). (B) The  ELISA results are expressed as mean duplicate OD490nm and are shown for  day 14 (•••••) and day 30 (−) pooled sera. Sera from control mice immunized with CFA, gave OD490nm < 0.1 at a serum dilution of 1:100.
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Figure 1: Immune response to rhRo60 in SJL/J (circles), A/J (squares), and BALB/c (triangles) mice immunized with rhRo60. T cell responses were studied in LNC proliferative assays (A) and antibody responses were determined by ELISA (B). The LNC proliferative responses are expressed as mean triplicate ΔCPM. In A, results are shown for mice immunized with rhRo60 (open symbols) and with CFA (filled symbols). (B) The ELISA results are expressed as mean duplicate OD490nm and are shown for day 14 (•••••) and day 30 (−) pooled sera. Sera from control mice immunized with CFA, gave OD490nm < 0.1 at a serum dilution of 1:100.

Mentions: T and B cell responses to rhRo60 were studied in SJL/J (H-2s), BALB/c (H-2d), and A/J (H-2a). All three strains mounted a strong T cell proliferative response to rhRo60 (Fig. 1 A). Strong antibody responses were also induced. Abs to the immunogen were readily detected 14 d after the initial immunization. By day 30, high antibody titers were generated and reactivity to rhRo60 was detectable at a serum dilution of 106 (Fig. 1 B). Control mice injected with CFA alone did not give specific T and B cell responses. Two other experiments gave similar results.


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)

Immune response to rhRo60 in SJL/J (circles), A/J (squares),  and BALB/c (triangles) mice immunized with rhRo60. T cell responses  were studied in LNC proliferative assays (A) and antibody responses were  determined by ELISA (B). The LNC proliferative responses are expressed  as mean triplicate ΔCPM. In A, results are shown for mice immunized  with rhRo60 (open symbols) and with CFA (filled symbols). (B) The  ELISA results are expressed as mean duplicate OD490nm and are shown for  day 14 (•••••) and day 30 (−) pooled sera. Sera from control mice immunized with CFA, gave OD490nm < 0.1 at a serum dilution of 1:100.
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Related In: Results  -  Collection

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getmorefigures.php?uid=PMC2192918&req=5

Figure 1: Immune response to rhRo60 in SJL/J (circles), A/J (squares), and BALB/c (triangles) mice immunized with rhRo60. T cell responses were studied in LNC proliferative assays (A) and antibody responses were determined by ELISA (B). The LNC proliferative responses are expressed as mean triplicate ΔCPM. In A, results are shown for mice immunized with rhRo60 (open symbols) and with CFA (filled symbols). (B) The ELISA results are expressed as mean duplicate OD490nm and are shown for day 14 (•••••) and day 30 (−) pooled sera. Sera from control mice immunized with CFA, gave OD490nm < 0.1 at a serum dilution of 1:100.
Mentions: T and B cell responses to rhRo60 were studied in SJL/J (H-2s), BALB/c (H-2d), and A/J (H-2a). All three strains mounted a strong T cell proliferative response to rhRo60 (Fig. 1 A). Strong antibody responses were also induced. Abs to the immunogen were readily detected 14 d after the initial immunization. By day 30, high antibody titers were generated and reactivity to rhRo60 was detectable at a serum dilution of 106 (Fig. 1 B). Control mice injected with CFA alone did not give specific T and B cell responses. Two other experiments gave similar results.

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