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Oxidation of defined antigens allows protein unfolding and increases both proteolytic processing and exposes peptide epitopes which are recognized by specific T cells
Author(s) -
Eugenio CarrascoMarín,
Jesús E. Paz-Miguel,
Paz López-Mato,
Carmen Álvarez-Domínguez,
Francisco Leyva-Cobián
Publication year - 1998
Publication title -
immunology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.297
H-Index - 133
eISSN - 1365-2567
pISSN - 0019-2805
DOI - 10.1046/j.1365-2567.1998.00618.x
Subject(s) - antigen processing , antigen , biochemistry , chemistry , epitope , antigen presentation , biology , cytotoxic t cell , in vitro , immunology
The participation of oxidative mechanisms in major histocompatibility complex (MHC) class II‐restricted antigen presentation was studied in vitro . In general, antigen processing is inhibited when peritoneal macrophages (MØ) are incubated with scavengers of reactive oxygen intermediates (ROI): mannitol (an ·OH scavenger), dimethylurea (DMTU, which reacts with H 2 O 2 and HOCl) and NCO‐700 (an epoxysuccinic acid derivative which inhibits oxidant production by activated phagocytes and can scavenge reactive oxygen species in both NaOCl and hypoxanthine (XOD) systems). However, neither rotenone and antimycins (inhibitors of O−2 production at the NADH dehydrogenase and ubiquinone–cytochrome b regions, respectively) nor aminoguanidine (an inducible nitric oxide synthase inhibitor) impaired antigen presentation, thus indirectly discarding the participation of mitochondrial oxidation and reactive nitrogen intermediates (RNI) in antigen processing. ROI scavengers do not inhibit the MHC class II‐restricted presentation of antigens that need processing but have their disulphide bonds reduced. It can be shown that oxidation of protein antigens (either by chlorination or performic acid treatment) allow protein unfolding and enhance both processing and exposure of immunogenic epitopes to specific T cells.