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Identification of HLA-A2-restricted CD8(+) cytotoxic T cell responses in primary biliary cirrhosis: T cell activation is augmented by immune complexes cross-presented by dendritic cells.

Kita H, Lian ZX, Van de Water J, He XS, Matsumura S, Kaplan M, Luketic V, Coppel RL, Ansari AA, Gershwin ME - J. Exp. Med. (2002)

Bottom Line: Very limited information on autoantigen-specific cytotoxic T lymphocyte (CTL) responses is available compared with autoreactive CD4(+) T cell responses.Furthermore, using soluble PDC-E2 complexed with either PDC-E2-specific human monoclonal antibody or affinity-purified autoantibodies against PDC-E2, the generation of PDC-E2-specific CTLs, occurred at 100-fold and 10-fold less concentration, respectively, compared with soluble antigen alone.The finding that autoantigen-immune complexes can not only cross-present but also that presentation of the autoantigen is of a higher relative efficiency, for the first time defines a unique role for autoantibodies in the pathogenesis of an autoimmune disease.

View Article: PubMed Central - PubMed

Affiliation: Division of Rheumatology, Allergy and Clinical Immunology, University of California at Davis School of Medicine, Davis, CA 95616, USA.

ABSTRACT
Primary biliary cirrhosis (PBC) is characterized by an intense biliary inflammatory CD4(+) and CD8(+) T cell response. Very limited information on autoantigen-specific cytotoxic T lymphocyte (CTL) responses is available compared with autoreactive CD4(+) T cell responses. Using peripheral blood mononuclear cells (PBMCs) from PBC, we identified an HLA-A2-restricted CTL epitope of the E2 component of pyruvate dehydrogenase (PDC-E2), the immunodominant mitochondrial autoantigen. This peptide, amino acids 159-167 of PDC-E2, induces specific MHC class I-restricted CD8(+) CTL lines from 10/12 HLA-A2(+) PBC patients, but not controls, after in vitro stimulation with antigen-pulsed dendritic cells (DCs). PDC-E2-specific CTLs could also be generated by pulsing DCs with full-length recombinant PDC-E2 protein. Furthermore, using soluble PDC-E2 complexed with either PDC-E2-specific human monoclonal antibody or affinity-purified autoantibodies against PDC-E2, the generation of PDC-E2-specific CTLs, occurred at 100-fold and 10-fold less concentration, respectively, compared with soluble antigen alone. Collectively, these data demonstrate that autoantibody, helper, and CTL epitopes all contain a shared peptide sequence. The finding that autoantigen-immune complexes can not only cross-present but also that presentation of the autoantigen is of a higher relative efficiency, for the first time defines a unique role for autoantibodies in the pathogenesis of an autoimmune disease.

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Induction of PD5-specific CTL lines with peptide, exogenous rPDC-E2 protein, or rPDC-E2 complexed with specific Abs. The cytotoxicity of CTL lines generated with the different Ags was tested against autologous BCL targets loaded with PD5 or control peptide at an E/T ratio of 40. (A) PBMCs from patient PBC10 were cocultured for 12 d with APCs loaded with rPDC-E2 protein or PD5 peptide at serial concentrations as indicated. (B) PBMCs from patient PBC9 were cocultured for 12 d with APCs loaded with serial concentrations of rPDC-E2 protein (as indicated) mixed with either human anti–PDC-E2 mAb, a control mAb, control ICs, or F(ab)′2 fragment of the human anti–PDC-E2 mAb. (C) PBMCs from patient PBC11 were cocultured for 12 d with APCs loaded with serial concentrations of rPDC-E2 protein (as indicated) mixed with affinity purified autoAbs from PBC sera or control Abs.
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fig4: Induction of PD5-specific CTL lines with peptide, exogenous rPDC-E2 protein, or rPDC-E2 complexed with specific Abs. The cytotoxicity of CTL lines generated with the different Ags was tested against autologous BCL targets loaded with PD5 or control peptide at an E/T ratio of 40. (A) PBMCs from patient PBC10 were cocultured for 12 d with APCs loaded with rPDC-E2 protein or PD5 peptide at serial concentrations as indicated. (B) PBMCs from patient PBC9 were cocultured for 12 d with APCs loaded with serial concentrations of rPDC-E2 protein (as indicated) mixed with either human anti–PDC-E2 mAb, a control mAb, control ICs, or F(ab)′2 fragment of the human anti–PDC-E2 mAb. (C) PBMCs from patient PBC11 were cocultured for 12 d with APCs loaded with serial concentrations of rPDC-E2 protein (as indicated) mixed with affinity purified autoAbs from PBC sera or control Abs.

Mentions: To determine if exogenous PDC-E2 protein can induce CTL lines specific for the MHC class I–restricted epitope PD5, PBMCs from three PBC patients (PBC9, PBC10, and PBC11) were cocultured with APCs loaded with rPDC-E2 protein or the PD5 peptide at various concentrations. CTL assays were performed against autologous BCLs targets loaded with either the PD5 peptide or a control peptide. CTL lines with PD5-specific cytotoxicity were consistently generated from each of the three PBC patients when PBMCs were stimulated with APCs loaded with PD5 peptide at concentrations >0.1 μM. However, when rPDC-E2 protein was used instead, PD5-specific CTL lines could only be generated when the PDC-E2 protein was added at the highest concentration (10 μM). Representative results of patient PBC10 is shown in Fig. 4 A. These data suggest that APCs exogenously pulsed with the soluble PDC-E2 protein, can still process and present the peptide by the MHC-class I molecule but at a relatively inefficient level.


Identification of HLA-A2-restricted CD8(+) cytotoxic T cell responses in primary biliary cirrhosis: T cell activation is augmented by immune complexes cross-presented by dendritic cells.

Kita H, Lian ZX, Van de Water J, He XS, Matsumura S, Kaplan M, Luketic V, Coppel RL, Ansari AA, Gershwin ME - J. Exp. Med. (2002)

Induction of PD5-specific CTL lines with peptide, exogenous rPDC-E2 protein, or rPDC-E2 complexed with specific Abs. The cytotoxicity of CTL lines generated with the different Ags was tested against autologous BCL targets loaded with PD5 or control peptide at an E/T ratio of 40. (A) PBMCs from patient PBC10 were cocultured for 12 d with APCs loaded with rPDC-E2 protein or PD5 peptide at serial concentrations as indicated. (B) PBMCs from patient PBC9 were cocultured for 12 d with APCs loaded with serial concentrations of rPDC-E2 protein (as indicated) mixed with either human anti–PDC-E2 mAb, a control mAb, control ICs, or F(ab)′2 fragment of the human anti–PDC-E2 mAb. (C) PBMCs from patient PBC11 were cocultured for 12 d with APCs loaded with serial concentrations of rPDC-E2 protein (as indicated) mixed with affinity purified autoAbs from PBC sera or control Abs.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC2196012&req=5

fig4: Induction of PD5-specific CTL lines with peptide, exogenous rPDC-E2 protein, or rPDC-E2 complexed with specific Abs. The cytotoxicity of CTL lines generated with the different Ags was tested against autologous BCL targets loaded with PD5 or control peptide at an E/T ratio of 40. (A) PBMCs from patient PBC10 were cocultured for 12 d with APCs loaded with rPDC-E2 protein or PD5 peptide at serial concentrations as indicated. (B) PBMCs from patient PBC9 were cocultured for 12 d with APCs loaded with serial concentrations of rPDC-E2 protein (as indicated) mixed with either human anti–PDC-E2 mAb, a control mAb, control ICs, or F(ab)′2 fragment of the human anti–PDC-E2 mAb. (C) PBMCs from patient PBC11 were cocultured for 12 d with APCs loaded with serial concentrations of rPDC-E2 protein (as indicated) mixed with affinity purified autoAbs from PBC sera or control Abs.
Mentions: To determine if exogenous PDC-E2 protein can induce CTL lines specific for the MHC class I–restricted epitope PD5, PBMCs from three PBC patients (PBC9, PBC10, and PBC11) were cocultured with APCs loaded with rPDC-E2 protein or the PD5 peptide at various concentrations. CTL assays were performed against autologous BCLs targets loaded with either the PD5 peptide or a control peptide. CTL lines with PD5-specific cytotoxicity were consistently generated from each of the three PBC patients when PBMCs were stimulated with APCs loaded with PD5 peptide at concentrations >0.1 μM. However, when rPDC-E2 protein was used instead, PD5-specific CTL lines could only be generated when the PDC-E2 protein was added at the highest concentration (10 μM). Representative results of patient PBC10 is shown in Fig. 4 A. These data suggest that APCs exogenously pulsed with the soluble PDC-E2 protein, can still process and present the peptide by the MHC-class I molecule but at a relatively inefficient level.

Bottom Line: Very limited information on autoantigen-specific cytotoxic T lymphocyte (CTL) responses is available compared with autoreactive CD4(+) T cell responses.Furthermore, using soluble PDC-E2 complexed with either PDC-E2-specific human monoclonal antibody or affinity-purified autoantibodies against PDC-E2, the generation of PDC-E2-specific CTLs, occurred at 100-fold and 10-fold less concentration, respectively, compared with soluble antigen alone.The finding that autoantigen-immune complexes can not only cross-present but also that presentation of the autoantigen is of a higher relative efficiency, for the first time defines a unique role for autoantibodies in the pathogenesis of an autoimmune disease.

View Article: PubMed Central - PubMed

Affiliation: Division of Rheumatology, Allergy and Clinical Immunology, University of California at Davis School of Medicine, Davis, CA 95616, USA.

ABSTRACT
Primary biliary cirrhosis (PBC) is characterized by an intense biliary inflammatory CD4(+) and CD8(+) T cell response. Very limited information on autoantigen-specific cytotoxic T lymphocyte (CTL) responses is available compared with autoreactive CD4(+) T cell responses. Using peripheral blood mononuclear cells (PBMCs) from PBC, we identified an HLA-A2-restricted CTL epitope of the E2 component of pyruvate dehydrogenase (PDC-E2), the immunodominant mitochondrial autoantigen. This peptide, amino acids 159-167 of PDC-E2, induces specific MHC class I-restricted CD8(+) CTL lines from 10/12 HLA-A2(+) PBC patients, but not controls, after in vitro stimulation with antigen-pulsed dendritic cells (DCs). PDC-E2-specific CTLs could also be generated by pulsing DCs with full-length recombinant PDC-E2 protein. Furthermore, using soluble PDC-E2 complexed with either PDC-E2-specific human monoclonal antibody or affinity-purified autoantibodies against PDC-E2, the generation of PDC-E2-specific CTLs, occurred at 100-fold and 10-fold less concentration, respectively, compared with soluble antigen alone. Collectively, these data demonstrate that autoantibody, helper, and CTL epitopes all contain a shared peptide sequence. The finding that autoantigen-immune complexes can not only cross-present but also that presentation of the autoantigen is of a higher relative efficiency, for the first time defines a unique role for autoantibodies in the pathogenesis of an autoimmune disease.

Show MeSH
Related in: MedlinePlus