title: Enhanced delivery of exogenous peptides into the class I antigen processing and presentation pathway.
abstract: Current immunization strategies, using peptide or protein antigens, generally fail to elicit cytotoxic-T-lymphocyte responses, since these antigens are unable to access intracellular compartments where loading of major histocompatibility complex class I (MHC-I) molecules occurs. In an attempt to circumvent this, we investigated whether the GM1 receptor-binding B subunit of Escherichia coli heat-labile toxin (EtxB) could be used to deliver class I epitopes. When a class I epitope was conjugated to EtxB, it was delivered into the MHC-I presentation pathway in a GM1-binding-dependent fashion and resulted in the appearance of MHC-I-epitope complexes at the cell surface. Importantly, we show that the efficiency of EtxB-mediated epitope delivery could be strikingly enhanced by incorporating, adjacent to the class I epitope, a 10-amino-acid segment from the C terminus of the DNA polymerase (Pol) of herpes simplex virus. The replacement of this 10-amino-acid segment by a heterologous sequence or the introduction of specific amino acid substitutions within this segment either abolished or markedly reduced the efficiency of class I epitope delivery. If the epitope was extended at its C terminus, EtxB-mediated delivery into the class I presentation pathway was found to be completely dependent on proteasome activity. Thus, by combining the GM1-targeting function of EtxB with the 10-amino-acid Pol segment, highly efficient delivery of exogenous epitopes into the endogenous pathway of class I antigen processing and presentation can be achieved.
authors: Department of Pathology & Microbiology, School of Medical Sciences, University of Bristol, Bristol BS8 1TD, United Kingdom.
authors: Lolke
authors: L
authors: De Haan
authors: Arron R
authors: AR
authors: Hearn
authors: A Jennifer
authors: AJ
authors: Rivett
authors: Timothy R
authors: TR
authors: Hirst
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D017951:Antigen Presentation / Q000276:immunology*; D001427:Bacterial Toxins / Q000276:immunology*; D002460:Cell Line; D003432:Cross-Linking Reagents; D003546:Cysteine Endopeptidases / Q000276:immunology; D004259:DNA-Directed DNA Polymerase / Q000276:immunology; D011992:Endosomes / Q000276:immunology; D004768:Enterotoxins / Q000276:immunology*; D018984:Epitopes, T-Lymphocyte / Q000276:immunology*; D029968:Escherichia coli Proteins; D005090:Exodeoxyribonucleases / Q000276:immunology; D006056:Golgi Apparatus / Q000276:immunology; D015395:Histocompatibility Antigens Class I / Q000276:immunology*; D051379:Mice; D008810:Mice, Inbred C57BL; D008969:Molecular Sequence Data; D009097:Multienzyme Complexes / Q000276:immunology; D019590:Nucleocapsid Proteins; D009698:Nucleoproteins / Q000276:immunology; D010047:Ovalbumin / Q000276:immunology; D010455:Peptides / Q000276:immunology; D046988:Proteasome Endopeptidase Complex; D016601:RNA-Binding Proteins; D011956:Receptors, Cell Surface / Q000276:immunology; D013388:Succinimides / Q000276:immunology; D013602:T-Lymphocytes, Cytotoxic / Q000276:immunology*; D014758:Viral Core Proteins / Q000276:immunology; D014764:Viral Proteins
chemical_list: D001427:Bacterial Toxins; D003432:Cross-Linking Reagents; D004768:Enterotoxins; D018984:Epitopes, T-Lymphocyte; D029968:Escherichia coli Proteins; D015395:Histocompatibility Antigens Class I; D009097:Multienzyme Complexes; C048842:NP protein, Influenza A virus; D019590:Nucleocapsid Proteins; D009698:Nucleoproteins; D010455:Peptides; D016601:RNA-Binding Proteins; D011956:Receptors, Cell Surface; D013388:Succinimides; D014758:Viral Core Proteins; D014764:Viral Proteins; C034993:ganglioside receptor; C032138:N-(gamma-maleimidobutyryloxy)succinimide; D010047:Ovalbumin; C027538:heat-labile enterotoxin, E coli; D004259:DNA-Directed DNA Polymerase; D005090:Exodeoxyribonucleases; C043417:DNA polymerase, Simplexvirus; D003546:Cysteine Endopeptidases; D046988:Proteasome Endopeptidase Complex