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Novel autoantigens immunogenic in COPD patients.

Leidinger P, Keller A, Heisel S, Ludwig N, Rheinheimer S, Klein V, Andres C, Hamacher J, Huwer H, Stephan B, Stehle I, Lenhof HP, Meese E - Respir. Res. (2009)

Bottom Line: Chronic obstructive pulmonary disease (COPD) is a respiratory inflammatory condition with autoimmune features including IgG autoantibodies.By in silico sequence analysis we found an enrichment of sequence motives previously associated with immunogenicity.The identification of novel immunogenic antigens is a first step towards a better understanding of the autoimmune component of COPD.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Human Genetics, Medical School, Saarland University, Building 60, 66421 Homburg/Saar, Germany. p.leidinger@mx.uni-saarland.de

ABSTRACT

Background: Chronic obstructive pulmonary disease (COPD) is a respiratory inflammatory condition with autoimmune features including IgG autoantibodies. In this study we analyze the complexity of the autoantibody response and reveal the nature of the antigens that are recognized by autoantibodies in COPD patients.

Methods: An array of 1827 gridded immunogenic peptide clones was established and screened with 17 sera of COPD patients and 60 healthy controls. Protein arrays were evaluated both by visual inspection and a recently developed computer aided image analysis technique. By this computer aided image analysis technique we computed the intensity values for each peptide clone and each serum and calculated the area under the receiver operator characteristics curve (AUC) for each clone and the separation COPD sera versus control sera.

Results: By visual evaluation we detected 381 peptide clones that reacted with autoantibodies of COPD patients including 17 clones that reacted with more than 60% of the COPD sera and seven clones that reacted with more than 90% of the COPD sera. The comparison of COPD sera and controls by the automated image analysis system identified 212 peptide clones with informative AUC values. By in silico sequence analysis we found an enrichment of sequence motives previously associated with immunogenicity.

Conclusion: The identification of a rather complex humoral immune response in COPD patients supports the idea of COPD as a disease with strong autoimmune features. The identification of novel immunogenic antigens is a first step towards a better understanding of the autoimmune component of COPD.

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Intensity values of MCM3 shown for all COPD and control sera. A: MCM3 intensity values shown for each serum. Sera of COPD patients are indicated by blue circles and control sera are indicated by red circles. For this clone, signals with low intensities are mostly found with control sera and signals with higher intensities are mostly found with COPD sera. B: Example of seroreactivity signals. The position of the analyzed clone is indicated by red rectangles. Each clone of the array is spotted in duplicate. By visual analysis, this clone was found positive with all shown COPD sera and negative with all shown normal sera.
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Figure 5: Intensity values of MCM3 shown for all COPD and control sera. A: MCM3 intensity values shown for each serum. Sera of COPD patients are indicated by blue circles and control sera are indicated by red circles. For this clone, signals with low intensities are mostly found with control sera and signals with higher intensities are mostly found with COPD sera. B: Example of seroreactivity signals. The position of the analyzed clone is indicated by red rectangles. Each clone of the array is spotted in duplicate. By visual analysis, this clone was found positive with all shown COPD sera and negative with all shown normal sera.

Mentions: The best clone (AUC = 0.10) showed sequence homology to FAM36A but represents an out of frame sequence. The spot intensities of clone FAM36A for all sera and the distribution (frequency) of seroreactivity signals according to the spot intensities are shown in Figure 4. The best in frame clone (AUC = 0.87) showed sequence homology to MCM3 that has been identified as immunogenic antigen in colon and prostate cancer. The above mentioned clone FAM36A showed higher immunogenicity in control sera than in COPD sera. Clone MCM3, the best in frame clone, showed higher immunogenicity in COPD sera than in control sera (see Figure 5). In total, 40 of the 67 in frame clones showed higher immunogenicity in COPD sera than in control sera, whereas only 27 of the 67 in frame clones showed higher immunogenicity in control sera than in COPD sera. In addition, 17 clones showed homology to proteins that were identified as immunogenic antigens in various human cancers . These proteins included NME2, CDC42BPB, RPS2, PTBP1, SON, MCM3, CD320, VIM, CENPB, PDE4DIP, CCNL2, HMG-14, HSPD1, MAZ, RPL6, STUB1, and MBTPS1. Antigens YBX1, HMG-14, and CENPB which showed also informative AUC values are involved in the autoimmune disease systemic sclerosis. CENPB was additionally associated with the autoimmune diseases lupus erythematosus and rheumatoid arthritis [12-15]. Clones with homology to TRAF4 and NME2 have previously been associated with non-cancer lung diseases. More information on all 67 clones is summarized in Additional file 1.


Novel autoantigens immunogenic in COPD patients.

Leidinger P, Keller A, Heisel S, Ludwig N, Rheinheimer S, Klein V, Andres C, Hamacher J, Huwer H, Stephan B, Stehle I, Lenhof HP, Meese E - Respir. Res. (2009)

Intensity values of MCM3 shown for all COPD and control sera. A: MCM3 intensity values shown for each serum. Sera of COPD patients are indicated by blue circles and control sera are indicated by red circles. For this clone, signals with low intensities are mostly found with control sera and signals with higher intensities are mostly found with COPD sera. B: Example of seroreactivity signals. The position of the analyzed clone is indicated by red rectangles. Each clone of the array is spotted in duplicate. By visual analysis, this clone was found positive with all shown COPD sera and negative with all shown normal sera.
© Copyright Policy - open-access
Related In: Results  -  Collection

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Show All Figures
getmorefigures.php?uid=PMC2667165&req=5

Figure 5: Intensity values of MCM3 shown for all COPD and control sera. A: MCM3 intensity values shown for each serum. Sera of COPD patients are indicated by blue circles and control sera are indicated by red circles. For this clone, signals with low intensities are mostly found with control sera and signals with higher intensities are mostly found with COPD sera. B: Example of seroreactivity signals. The position of the analyzed clone is indicated by red rectangles. Each clone of the array is spotted in duplicate. By visual analysis, this clone was found positive with all shown COPD sera and negative with all shown normal sera.
Mentions: The best clone (AUC = 0.10) showed sequence homology to FAM36A but represents an out of frame sequence. The spot intensities of clone FAM36A for all sera and the distribution (frequency) of seroreactivity signals according to the spot intensities are shown in Figure 4. The best in frame clone (AUC = 0.87) showed sequence homology to MCM3 that has been identified as immunogenic antigen in colon and prostate cancer. The above mentioned clone FAM36A showed higher immunogenicity in control sera than in COPD sera. Clone MCM3, the best in frame clone, showed higher immunogenicity in COPD sera than in control sera (see Figure 5). In total, 40 of the 67 in frame clones showed higher immunogenicity in COPD sera than in control sera, whereas only 27 of the 67 in frame clones showed higher immunogenicity in control sera than in COPD sera. In addition, 17 clones showed homology to proteins that were identified as immunogenic antigens in various human cancers . These proteins included NME2, CDC42BPB, RPS2, PTBP1, SON, MCM3, CD320, VIM, CENPB, PDE4DIP, CCNL2, HMG-14, HSPD1, MAZ, RPL6, STUB1, and MBTPS1. Antigens YBX1, HMG-14, and CENPB which showed also informative AUC values are involved in the autoimmune disease systemic sclerosis. CENPB was additionally associated with the autoimmune diseases lupus erythematosus and rheumatoid arthritis [12-15]. Clones with homology to TRAF4 and NME2 have previously been associated with non-cancer lung diseases. More information on all 67 clones is summarized in Additional file 1.

Bottom Line: Chronic obstructive pulmonary disease (COPD) is a respiratory inflammatory condition with autoimmune features including IgG autoantibodies.By in silico sequence analysis we found an enrichment of sequence motives previously associated with immunogenicity.The identification of novel immunogenic antigens is a first step towards a better understanding of the autoimmune component of COPD.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Human Genetics, Medical School, Saarland University, Building 60, 66421 Homburg/Saar, Germany. p.leidinger@mx.uni-saarland.de

ABSTRACT

Background: Chronic obstructive pulmonary disease (COPD) is a respiratory inflammatory condition with autoimmune features including IgG autoantibodies. In this study we analyze the complexity of the autoantibody response and reveal the nature of the antigens that are recognized by autoantibodies in COPD patients.

Methods: An array of 1827 gridded immunogenic peptide clones was established and screened with 17 sera of COPD patients and 60 healthy controls. Protein arrays were evaluated both by visual inspection and a recently developed computer aided image analysis technique. By this computer aided image analysis technique we computed the intensity values for each peptide clone and each serum and calculated the area under the receiver operator characteristics curve (AUC) for each clone and the separation COPD sera versus control sera.

Results: By visual evaluation we detected 381 peptide clones that reacted with autoantibodies of COPD patients including 17 clones that reacted with more than 60% of the COPD sera and seven clones that reacted with more than 90% of the COPD sera. The comparison of COPD sera and controls by the automated image analysis system identified 212 peptide clones with informative AUC values. By in silico sequence analysis we found an enrichment of sequence motives previously associated with immunogenicity.

Conclusion: The identification of a rather complex humoral immune response in COPD patients supports the idea of COPD as a disease with strong autoimmune features. The identification of novel immunogenic antigens is a first step towards a better understanding of the autoimmune component of COPD.

Show MeSH
Related in: MedlinePlus