NOD.c3c4 congenic mice develop autoimmune biliary disease that serologically and pathogenetically models human primary biliary cirrhosis

Primary biliary cirrhosis (PBC) is an autoimmune disease with a strong genetic component characterized by biliary ductular inflammation with eventual liver cirrhosis. The serologic hallmark of PBC is antimitochondrial antibodies that react with the pyruvate dehydrogenase complex, targeting the inner lipoyl domain of the E2 subunit (anti–PDC-E2). Herein we demonstrate that NOD.c3c4 mice congenically derived from the nonobese diabetic strain develop an autoimmune biliary disease (ABD) that models human PBC. NOD.c3c4 (at 9–10 wk, before significant biliary pathology) develop antibodies to PDC-E2 that are specific for the inner lipoyl domain. Affected areas of biliary epithelium are infiltrated with CD3+, CD4+, and CD8+ T cells, and treatment of NOD.c3c4 mice with monoclonal antibody to CD3 protects from ABD. Furthermore, NOD.c3c4-scid mice develop disease after adoptive transfer of splenocytes or CD4+ T cells, demonstrating a central role for T cells in pathogenesis. Histological analysis reveals destructive cholangitis, granuloma formation, and eosinophilic infiltration as seen in PBC, although, unlike PBC, the extrahepatic biliary ducts are also affected. Using a congenic mapping approach, we define the first ABD (Abd) locus, Abd1. These results identify the NOD.c3c4 mouse as the first spontaneous mouse model of PBC.

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PDC-E2, a Common Auto Antigen in Primary Biliary Cirrhosis (PBC) Is Also a Target of an Antibody Response in Patients Who Achieve Complete Remission after Donor Lymphocyte Infusion.

Blood ◽

10.1182/blood.v104.11.2121.2121 ◽

2004 ◽

Vol 104 (11) ◽

pp. 2121-2121

Author(s):

Roberto Bellucci ◽

Meagan Gallagher ◽

Hong-Nam Nguyen ◽

Edwin P. Alyea ◽

Emmanuel Zorn ◽

...

Keyword(s):

T Cell ◽

Primary Biliary Cirrhosis ◽

Antibody Response ◽

Pyruvate Dehydrogenase Complex ◽

Cdna Expression Library ◽

Biliary Cirrhosis ◽

Allogeneic Bone ◽

Antibody Reactivity ◽

Inner Lipoyl Domain ◽

Lipoyl Domain

Abstract The ability of donor lymphocyte infusions (DLI) to induce complete responses (CR) in patients with relapsed multiple myeloma (MM) following allogeneic bone marrow transplantation provides clear evidence of graft-versus-myeloma (GVM) immunity. To identify GVM associated target antigens, we previously screened an MM cDNA expression library with post DLI serum from 5 MM patients who achieved CR after DLI. One of the antigens identified in the screening was dihydrolipoamide acetyltranferase the E2 component of the pyruvate dehydrogenase complex (PDC-E2). Using a phage plate assay, antibody reactivity against PDC-E2 was found in 2 of 9 MM and 1 of 5 chronic myeloid leukemia (CML) patients who achieved a CR after DLI. No antibodies were found before DLI, in 20 normal donors, 10 patients who underwent T-cell depleted allogeneic BMT, 6 MM DLI non-responders and 20 patients with chronic GVHD. Primary biliary cirrhosis (PBC) is an autoimmune liver disease in which more than 80% of patients have autoantibodies against PDC-E2. In patients with PBC the major immunogenic epitope of PDC-E2 has been mapped to the region associated with the inner lipoyl domain. To better characterize the antibody response in MM patients who had a CR after DLI a GST-PDC-E2 fusion protein was purified and used to quantify the antibody response by ELISA. Using this sensitive assay we found 1 additional MM DLI responder who had antibody reactivity against PDC-E2. Analysis performed at serial time points after DLI showed that reactivity persisted for 1.5 and 3 years after DLI in two MM patients and 3 years after DLI in the CML DLI responder. To map the antibody response after DLI and compare this to antibody reactivity in patients with PBC, we synthesized a series of 85 overlapping peptides covering the entire length of PDC-E2 and analyzed the specificity of the antibody response by ELISA. Using this assay, post-DLI serum was found to be reactive against 4 peptides located in the E2 catalytic domain of PDC-E2 but no reactivity was detected against peptides located in the inner lipoyl domain of the protein, the region commonly recognized by auto-antibodies in PBC. Analysis of serial samples showed that the antibody response persisted against these peptides up to 2–3 years after DLI but no reactivity was found pre-DLI and in normal serum. In conclusion we show that PDC-E2, a common auto-antigen in the autoimmune disease PBC, is also the target of an antibody response in patients with MM and CML who achieve a CR after DLI. The antibody response found after DLI is directed against a different region of the protein. Further studies characterizing T cell epitopes in these patients are underway and they will help to better characterize the immune response against PDC-E2 in patients after DLI.

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Autoreactive liver-infiltrating T cells in primary biliary cirrhosis recognize inner mitochondrial epitopes and the pyruvate dehydrogenase complex

Journal of Hepatology ◽

10.1016/s0168-8278(05)80276-4 ◽

1993 ◽

Vol 18 (3) ◽

pp. 322-327 ◽

Cited By ~ 33

Author(s):

H. Löhr ◽

B. Fleischer ◽

G. Gerken ◽

S.J. Yeaman ◽

K.-H. Meyer zum Büschenfelde ◽

...

Keyword(s):

T Cells ◽

Primary Biliary Cirrhosis ◽

Pyruvate Dehydrogenase ◽

Pyruvate Dehydrogenase Complex ◽

Biliary Cirrhosis ◽

Dehydrogenase Complex

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HLA DRB4 0101-restricted immunodominant T cell autoepitope of pyruvate dehydrogenase complex in primary biliary cirrhosis: evidence of molecular mimicry in human autoimmune diseases.

Journal of Experimental Medicine ◽

10.1084/jem.181.5.1835 ◽

1995 ◽

Vol 181 (5) ◽

pp. 1835-1845 ◽

Cited By ~ 210

Author(s):

S Shimoda ◽

M Nakamura ◽

H Ishibashi ◽

K Hayashida ◽

Y Niho

Keyword(s):

T Cell ◽

Primary Biliary Cirrhosis ◽

Molecular Mimicry ◽

Cell Clone ◽

Pyruvate Dehydrogenase Complex ◽

Biliary Cirrhosis ◽

T Cell Clones ◽

Cell Clones ◽

T Cell Clone ◽

Lipoyl Domain

We established six T cell clones specific for pyruvate dehydrogenase complex (PDC)-E2 peptides from four different patients with primary biliary cirrhosis using 33 different peptides of 17-20 amino acid residues corresponding to human PDC-E2 as stimulating antigens. The minimal T cell epitopes of these six T cell clones were all mapped to the same region of the PDC-E2 peptide 163-176 (GDLLAEIETDKATI), which corresponds to the inner lipoyl domain of PDC-E2. The HLA restriction molecules for this epitope were all identified as HLA DRB4 0101. The common essential amino acids of this epitope for these T cell clones were E, D, and K at positions 170, 172, and 173, respectively; other crucial amino acids for this epitope differed in each T cell clone. In addition, the alanine-substituted peptides at positions 170 and 173, but not 172, inhibited the proliferation of all T cell clones induced by the original peptide of human PDC-E2 163-176, indicating that amino acid D at position 172 is a critical MHC-binding site for all T cell clones tested. Interestingly, all T cell clones reacted to PDC-E2 peptide 36-49 (GDLIAEVETDKATV), which corresponds to the outer lipoyl domain of human PDC-E2. Furthermore, one T cell clone cross-reacted with exogenous antigens such as Escherichia coli PDC-E2 peptide 31-44/134-147/235-248 (EQSLITVEGDKASM), which has an EXDK sequence. This is a definite demonstration of the presence of molecular mimicry at the T cell clonal level in human autoimmune diseases. It is also considered possible to design peptide-specific immunotherapy based on the findings of T cell autoepitopes in primary biliary cirrhosis.

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