H-2Ld class I molecule protects an HIV N-extended epitope from in vitro trimming by endoplasmic reticulum aminopeptidase associated with antigen processing

• Published in: The Journal of immunology (1950) 2010-04, Vol.184 (7), p.3351-3355
• Main Authors: Infantes, Susana, Samino, Yolanda, Lorente, Elena, Jiménez, Mercedes, García, Ruth, Del Val, Margarita, López, Daniel
• Format: Article
• Language: English
• Subjects: Animals; Antigen Presentation - immunology; Cells, Cultured; Endoplasmic Reticulum - immunology; Endoplasmic Reticulum - metabolism; Epitopes, T-Lymphocyte - immunology; Epitopes, T-Lymphocyte - metabolism; H-2 Antigens - immunology; H-2 Antigens - metabolism; Histocompatibility Antigen H-2D; HIV Envelope Protein gp120 - immunology; HIV Envelope Protein gp120 - metabolism; Humans; Leucyl Aminopeptidase - immunology; Leucyl Aminopeptidase - metabolism; Mice; Recombinant Proteins - immunology; Recombinant Proteins - metabolism; Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization
• ISSN: 1550-6606
• DOI: 10.4049/jimmunol.0901560

In the classical MHC class I Ag presentation pathway, antigenic peptides derived from viral proteins by multiple proteolytic cleavages are transported to the endoplasmic reticulum lumen and are then exposed to ami-nopeptidase activity. In the current study, a long MHC class I natural ligand recognized by cytotoxic T lymphocytes was used to study the kinetics of degradation by aminopeptidase. The in vitro data indicate that this N-extended peptide is efficiently trimmed to a 9-mer, unless its binding to the MHC molecules protects the full-length peptide.