Identification of the main epitope on human cytochrome P450 IID6 recognized by anti-liver kidney microsome antibody

Guéguen, M.; Boniface, Odile; Bernard, Olivier; Clerc, François; Cartwright, Terence; Álvarez, Fernando

doi:10.1016/0896-8411(91)90180-k

Cited by 70 publications

(61 citation statements)

References 13 publications

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“…With this approach, we were able to confirm both existence and recognition frequency of the previously described epitopes. In agreement with Yamamoto et al (12), we found that CYP2D6 [253][254][255][256][257][258][259][260][261][262][263][264][265][266][267][268][269][270][271][272] , encompassing the hitherto considered main epitope (10), was recognized by 85% of our patients with LKM1 AIH and by only 1 of 10 LKM1-positive HCV-infected patients.…”

Section: Discussionsupporting

confidence: 76%

“…In each plate, two wells were used as blanks, in which serum and peptide were omitted, and two additional wells were used for a positive and a negative control. The positive control consisted of an LKM1-positive serum (titer 1/5120), which in preliminary experiments was shown to react with CYP2D6 253-272 , containing a previously described immunodominant epitope (10). A randomly generated scrambled control peptide incubated with serum from a healthy individual was used as negative control.…”

Section: Elisamentioning

confidence: 99%

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Cytochrome P4502D6193–212: A New Immunodominant Epitope and Target of Virus/Self Cross-Reactivity in Liver Kidney Microsomal Autoantibody Type 1-Positive Liver Disease

Kerkar

Choudhuri

et al. 2003

The Journal of Immunology

196

143

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Cytochrome P4502D6 (CYP2D6), target of liver kidney microsomal autoantibody type 1 (LKM1), characterizes autoimmune hepatitis type 2 (AIH2) but is also found in patients with chronic hepatitis C virus (HCV) infection. To provide a complete linear epitope B cell map of CYP2D6, we tested peptides spanning the entire sequence of CYP2D6. In addition to confirming previously described antigenic sites, we identified four new epitopes (193–212, 238–257, 268–287, and 478–497). CYP2D6193–212 is immunodominant and was the target of 12 of 13 (93%) patients with AIH2 and 5 of 10 (50%) HCV/LKM1-positive patients. Because LKM1 is present in both AIH2 and a viral infection, we tested whether Abs to CYP2D6193–212 arise through cross-reactive immunity between virus and self. We identified a hexameric sequence “RLLDLA” sharing 5 of 6 aa with “RLLDLS” of HCV2985–2990 and all 6 aa with CMV130–135. Of 17 CYP2D6193–212-reactive sera, 11 (7 AIH and 4 HCV) reacted by ELISA with the HCV homologue, 8 (5 AIH and 3 HCV) with the CMV homologue, and 8 (5 AIH and 3 HCV) showed double reactivity. Autoantibody binding to CYP2D6193–212 was inhibited by preincubation with HCV2977–2996 or CMV121–140. Recombinant HCV-nonstructural protein 5 and CMV-UL98 proteins also inhibited Ab binding to CYP2D6193–212. Affinity-purified CYP2D6193–212-specific Ab inhibited the metabolic activity of CYP2D6. The demonstrated similarity and cross-reactivity between CYP2D6193–212 and two unrelated viruses suggests that multiple exposure to viruses mimicking self may represent an important pathway to the development of autoimmunity.

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Section: Discussionsupporting

confidence: 76%

Section: Elisamentioning

confidence: 99%

Cytochrome P4502D6193–212: A New Immunodominant Epitope and Target of Virus/Self Cross-Reactivity in Liver Kidney Microsomal Autoantibody Type 1-Positive Liver Disease

Kerkar

Choudhuri

et al. 2003

The Journal of Immunology

196

143

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“…The best test to differentiate between LKM1 antibodies from AIH-2 patients and from HCVinfected patients would be a test which uses immunogenic sites recognized exclusively by AIH-2 sera. For example, this test could be an ELISA using the synthetic peptide representing the main P450IID6 antigenic site (aa 262-269) as antigen for LKM1 antibodies in serum from AIH-2 patients [15][16][17], which is very infrequently recognized by LKM1 /HCV sera [28] Eventually, synthetic peptides representing P450IID6 sequences aa 373-389 and 410-429, only recognized by some AIH patients' sera, could be added [17].…”

Section: Discussionmentioning

confidence: 99%

“…The main immunogenic site on P450IID6 recognized by LKM1 /HCV ÿ sera from patients with AIH-2 was found to be localized between aa 262 and 269, which is in the P450IID6 region containing the LKM1 /HCV immunogenic sites [15][16][17]. The aim of the present study was to identify specific antigenic sites on the P450IID6 molecule.…”

Section: Introductionmentioning

confidence: 90%

Study of the B cell response to cytochrome P450IID6 in sera from chronic hepatitis C patients

Parez

Herzog

Jacqz-Aigrain

et al. 1996

Clinical and Experimental Immunology

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SUMMARYSome patients with chronic hepatitis C develop liver/kidney microsome type 1 antibodies. Some of these autoantibodies are directed against the cytochrome P450IID6. The aim of this study was to characterize the immunogenic sites on the P450IID6 molecule recognized by autoantibodies from individuals infected with the hepatitis C virus. Serum from 24 patients with markers of hepatitis C infection and liver/kidney microsome type 1 antibodies were tested by immunoblotting with human liver microsomal proteins. Eight of them with anti-P450IID6 antibodies were tested with synthetic peptides representing P450IID6 putative immunogenic sites and for their capacity to inhibit in vitro P450IID6 enzymatic activity. Anti-P450IID6 antibodies in the sera of chronic hepatitis C patients were of IgG subclass 1 and in one patient also of IgM type. These sera recognized different P450IID6 peptide sequences consisting of amino acids (aa) 200-214 and aa 271-339. The synthetic peptide between aa 321 and 339 appears to represent the main antigenic site. Five out of eight anti-P450IID6 positive sera were also able to inhibit P450IID6 enzymatic activity in vitro at a dilution of 1 : 100. The anti-P450IID6 autoimmune response in chronic hepatitis C patients is polyclonal, probably inducible, and maintained by the liberation of P450IID6 by hepatocyte lysis. The characterization of the P450IID6 immunogenic site recognized by patients with hepatitis C infection may enable a specific test to be designed to identify those patients with autoimmune hepatitis type 2.

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“…The major epitopes recognized by LKM-1 antibody were reported to span amino acids 257-269 and 321-351 of CYP2D6. 6,16,17) Peptides 246-281 and 284-391 in this study include these regions. Peptide 284-391 was recognized by both HCV-negative and positive sera but Table 2) was used at 1000-fold dilution.…”

Section: Comparison Of Immunoreactivity Of Lkm-1 Serum With Hcv-positmentioning

confidence: 99%

A New Epitope of CYP2D6 Recognized by Liver Kidney Microsomal Autoantibody from Japanese Patients with Autoimmune Hepatitis

Imaoka

Obata

Hiroi

et al. 2005

Biological & Pharmaceutical Bulletin

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Autoantibodies to liver-kidney microsomes (LKM) were first characterized by immunofluorescence microscopy using rat liver and kidney sections.1) These autoantibodies have been classified into three groups (anti-LKM-1, 2, and 3) according to differences in immnofluorescent staining patterns.1-3) Anti-LKM-1 is found in a subgroup of patients with autoimmune hepatitis (AIH) II and the presence of LKM-1 antibodies is one of the most important criteria for the diagnosis of AIH-II. But anti-LKM-1 is not completely specific to AIH-II. LKM-1 antibody is also produced in the course of chronic hepatitis (CH) C and is detected in about 2-10% of CHC patients. 4,5) In the case of AIH-II, there is no evidence of HCV infection. The pathological profile of AIH-II is quite different from that of CHC. Patients with AIH-II are young and responsive to immunosuppressive drugs. In contrast, patients with CHC tend to be older and have different pathological conditions. Manns et al. 6) suggested that molecular mimicry between the LKM-1 antigen and CHC viral antigen causes LKM-1 antibody to be produced in CHC patients and the presence of LKM-1 antibody does not affect the clinical and biochemical profiles of CHC. In Japan, patients with AIH-II are very rare while there are many patients with CHC, implying that LKM-1-positive patients with CHC outnumber those with AIH-II. 7) Therefore, it is very important to detect AIH-II specifically.The major autoantigen for LKM-1 has been identified as CYP2D6 which is an isoform of cytochrome P450s and has an important role in the metabolism of many drugs in the liver. 8,9) The mechanism of production of LKM-1 antibodies remains unclear but ethnic differences among patients with AIH-II may provide a clue.10) CYP2D6 reveals extensive genetic polymorphism and catalytic activity toward a range of drugs. About 10% of Caucasians have a complete deletion of the CYP2D6 gene but less than 1% of Japanese have such a mutation. 11,12) In Japan, patients with AIH-II are very rare. 7)There may be a relationship between genetic polymorphisms in CYP2D6 and AIH-II in Japanese. 10) LKM-1 antibody recognition sites has been identified in the internal amino acid sequence in CYP2D6. The sequence 257-269 of CYP2D6 was found to be the core of an immunodominant epitope recognized by most anti-LKM-1. 6,9) The antibody also recognizes the amino acid sequences 196-218 and 321-351. 9,13) The antibody from CHC also recognizes some of these sequences.In this study, we systemically investigated epitopes of CYP2D6 recognized specifically by LKM-1 antibody but not CHC antibody to develop a method of distinguishing LKM-1 antibody from CHC antibody. A full-length CYP2D6 was expressed in Escherichia coli and purified. CYP2D6 was digested by several proteases. The resulting peptides were separated by HPLC and each peptide fragment was reacted with LKM-1 and CHC antibodies. The sequence of each peptide was determined and a specific epitope for LKM-1 antibody was identified. MATERIALS AND METHODSPatient Sera Sera were collected from p...

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Identification of the main epitope on human cytochrome P450 IID6 recognized by anti-liver kidney microsome antibody

Cited by 70 publications

References 13 publications

Cytochrome P4502D6193–212: A New Immunodominant Epitope and Target of Virus/Self Cross-Reactivity in Liver Kidney Microsomal Autoantibody Type 1-Positive Liver Disease

Cytochrome P4502D6193–212: A New Immunodominant Epitope and Target of Virus/Self Cross-Reactivity in Liver Kidney Microsomal Autoantibody Type 1-Positive Liver Disease

Study of the B cell response to cytochrome P450IID6 in sera from chronic hepatitis C patients

A New Epitope of CYP2D6 Recognized by Liver Kidney Microsomal Autoantibody from Japanese Patients with Autoimmune Hepatitis

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