Presentation of an influenza nucleoprotein epitope incorporated into the H-2Db signal sequence requires the transporter-associated with antigen presentation.
In an effort to optimize the formation of peptide-specific CTL target structures in the context of plasmid DNA immunization, a strategy was developed to couple the biosynthesis of a class I heavy chain with its optimal binding epitope. Specifically, a cDNA expression vector was constructed with the influenza nucleoprotein epitope NP366-74 incorporated into the signal sequence of its restriction element H-2Db. Transporter associated with Ag presentation-expressing murine cell lines P815 (H-2d) and BW5147 (H-2k) transfected with this modified heavy chain expressed normal levels of plasmid-encoded Db at the cell surface, and were lysed by NP366-74-specific CTL. These results indicate that the modified signal sequence was successfully delivered to the endoplasmic reticulum, and the epitope within it processed for T cell recognition. In contrast, T2 cells, which lack the TAP transporter, when transfected with the same vector were not lysed by NP366-74 CTL, and exhibited an Ag-processing-defective phenotype. Thus, these data, which indicate TAP-dependent presentation of an optimal CTL epitope located in a signal sequence, challenge the effectiveness of Ag processing in the endoplasmic reticulum.
Uger
R A
RA
Department of Immunology, Medical Sciences Building, University of Toronto, Canada.
Barber
B H
BH
D000071181:ATP Binding Cassette Transporter, Subfamily B, Member 2; D018528:ATP-Binding Cassette Transporters / Q000276:immunology*; D000595:Amino Acid Sequence; D000818:Animals; D017951:Antigen Presentation / Q000276:immunology*; D000939:Epitopes / Q000276:immunology*; D006183:H-2 Antigens / Q000276:immunology*; D064532:Histocompatibility Antigen H-2D; D051379:Mice; D008810:Mice, Inbred C57BL; D008969:Molecular Sequence Data; D009975:Orthomyxoviridae / Q000276:immunology*; D021382:Protein Sorting Signals / Q000276:immunology*; D011994:Recombinant Proteins / Q000276:immunology; D014407:Tumor Cells, Cultured; D014758:Viral Core Proteins / Q000276:immunology*
D000071181:ATP Binding Cassette Transporter, Subfamily B, Member 2; D018528:ATP-Binding Cassette Transporters; D000939:Epitopes; D006183:H-2 Antigens; D064532:Histocompatibility Antigen H-2D; D021382:Protein Sorting Signals; D011994:Recombinant Proteins; C073119:TAP1 protein, human; C486171:Tap1 protein, mouse; D014758:Viral Core Proteins