Definition of Haptens Derived from Sulfamethoxazole: In Vitro and in Vivo.
Chem Res Toxicol
; 32(10): 2095-2106, 2019 10 21.
Article
em En
| MEDLINE
| ID: mdl-31468968
ABSTRACT
Hypersensitivity reactions occur frequently in patients upon treatment with sulfamethoxazole (SMX). These adverse effects have been attributed to nitroso sulfamethoxazole (SMX-NO), the reactive product formed from auto-oxidation of the metabolite SMX hydroxylamine. The ability of SMX-NO to prime naïve T-cells in vitro and also activate T-cells derived from hypersensitive patients has illustrated that T-cell activation may occur through the binding of SMX-NO to proteins or through the direct modification of MHC-bound peptides. SMX-NO has been shown to modify cysteine residues in glutathione, designer peptides, and proteins in vitro; however, the presence of these adducts have not yet been characterized in vivo. In this study a parallel in vitro and in vivo analysis of SMX-NO adducts was conducted using mass spectrometry. In addition to the known cysteine adducts, multiple SMX-NO-derived haptenic structures were found on lysine and tyrosine residues of human serum albumin (HSA) in vitro. On lysine residues two haptenic structures were identified including an arylazoalkane adduct and a Schiff base adduct. Interestingly, these adducts are labile to heat and susceptible to hydrolysis as shown by the presence of allysine. Furthermore, SMX-modified HSA adducts were detected in patients on long-term SMX therapy illustrated by the presence of an arylazoalkane adduct derived from a proposed carboxylic acid metabolite of SMX-NO. The presence of these adducts could provide an explanation for the immunogenicity of SMX and the strong responses to SMX-NO observed in T-cell culture assays. Also, the degradation of these adducts to allysine could lead to a stress-related innate immune response required for T-cell activation.
Texto completo:
1
Base de dados:
MEDLINE
Assunto principal:
Sulfametoxazol
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Linfócitos T
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Haptenos
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Compostos Nitrosos
Tipo de estudo:
Etiology_studies
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Incidence_studies
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Observational_studies
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Prognostic_studies
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Risk_factors_studies
Limite:
Humans
Idioma:
En
Ano de publicação:
2019
Tipo de documento:
Article