Human anti-endoplasmic reticulum antibodies in sera of patients with halothane-induced hepatitis are directed against a trifluoroacetylated carboxylesterase. Proc Natl Acad Sci USA

Laboratory of Chemical Pharmacology, National Heart, Lung and Blood Institute, Bethesda, MD 20892.
Proceedings of the National Academy of Sciences (Impact Factor: 9.67). 02/1989; 86(1):322-6. DOI: 10.1073/pnas.86.1.322
Source: PubMed


Previous studies have demonstrated that patients with halothane-induced hepatitis have serum antibodies that are directed against novel liver microsomal neoantigens and have suggested that these neoantigens may play an immunopathological role in development of the patients' liver damage. These investigations have further revealed that the antibodies are directed against distinct polypeptide fractions (100 kDa, 76 kDa, 59 kDa, 57 kDa, 54 kDa) that have been covalently modified by the reactive trifluoroacetyl halide metabolite of halothane. In this paper, the trifluoroacetylated (TFA) 59-kDa neoantigen (59-kDa-TFA) recognized by the patients' antibodies was isolated from liver microsomes of halothane-treated rats by chromatography on an immunoaffinity column of anti-TFA IgG. Antibodies were raised against the 59-kDa-TFA protein and were used to purify the native protein from liver microsomes of untreated rats. Based upon its apparent monomeric molecular mass, NH2-terminal amino acid sequence, catalytic activity, and other physical properties, the protein has been identified as a previously characterized microsomal carboxylesterase (EC A similar strategy may be used to purify and characterized neoantigens associated with other drug toxicities that are believed to have an immunopathological basis.

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Available from: Brian Michael Martin, Apr 02, 2014
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    • "Metabolites have also been implicated in adverse effects [e.g., the quinone-imine metabolite of acetaminophen (Manyike et al., 2000) and trifluoroacetyl chloride of halothane (Satoh et al., 1989)]. "
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    • "Ample evidence suggests that halothane hepatitis is caused by an immune reaction against endogenous proteins that have been covalently modified by the trifluoroacetyl chloride (TFA) metabolite of halothane (Kenna et al., 1988;Pohl, 1990). Sera from patients afflicted with halothane hepatitis contain specific antibodies recognizing TFA-modified liver proteins (Vergani et al., 1980;Satoh et al., 1989). TFA-protein adducts have also been detected in liver biopsies obtained from halothane hepatitis patients (Pohl et al., 1989). "
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    ABSTRACT: Immune-mediated adverse drug reactions (IADRs) represent a significant problem in clinical practice and drug development. Studies of the underlying mechanisms of IADRs have been hampered by the lack of animal models. Halothane causes severe allergic hepatitis with clinical features consistent with an IADR. Our ultimate goal is to develop a mouse model of halothane hepatitis. Evidence suggests that adaptive immune responses targeting liver protein adducts of the reactive metabolite (trifluoroacetyl (TFA)) play an important role in the pathogenesis. The present study demonstrated that the combination of an anti-CD40 antibody (Ab) and a Toll-like receptor (TLR) agonist served as a potent adjuvant in generating TFA-specific T cell responses in mice. Both CD4(+) and CD8(+) subsets of T cells were activated and the TFA-specific responses were detected not only in the spleen but also in the liver of mice immunized with mouse serum albumin adducts of TFA (TFA-MSA) plus the combined CD40/TLR agonist. Whereas all three TLR agonists examined were effective in eliciting TFA-specific immune responses in BALB/cByJ mice, only polyI:C was effective in DBA/1 mice and none of the TLR agonists could aid the generation of TFA-specific T cells in C57BL/6J mice. This result, combined with our previous finding that BALB/cByJ mice were the most susceptible to halothane-induced acute liver injury, provides the basis for employing this strain in future studies. Collectively, our data demonstrated the successful completion of a crucial first step in the development of a murine model of halothane hepatitis.
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    • "Among structurally similar anesthetics, which include halothane, isoflurane, and desflurane, the likelihood of causing IDR appears to correlate with the degree of reactive metabolite formation. Twenty percent of halothane is metabolized to trifloroacetyl chloride (TFA), and it is associated with the highest incidence of allergic hepatitis compared with isoflurane and desflurane, which are metabolized to TFA to much lesser degrees (Njoku et al. 1997; Satoh et al. 1989; Vergani et al. 1980). The sites of reactive metabolite formation often correlate with the major tissue targets of IDR. "
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