Epitope selection in major histocompatibility complex class I-mediated pathway is affected by the intracellular localization of an antigen

Eur J Immunol. 1997 Feb;27(2):347-53. doi: 10.1002/eji.1830270202.

Abstract

We analyzed the mode of antigen presentation of an endogenous antigen localized in the cytoplasm or in the mitochondria. Pseudomonas aeruginosa PAO leucine-, isoleucine-, valine-binding protein (LIVAT-BP) encoded by the braC gene was used as a model antigen. Using mouse BALB/3T3 cells, we established two LIVAT-BP transfectants by transfection of a plasmid harboring the intact braC or braC gene fused with the mitochondrial transport signal derived from the yeast COXIV gene. One of the resulting transfectants, BC-15, expressed LIVAT-BP in the cytoplasm, while YZ-710 cells expressed LIVAT-BP in the mitochondria. The splenic effector cells derived from BALB/c mice primed with BC-15 cells exhibited cytotoxic T lymphocyte (CTL) activity against BC-15 cells, but not against YZ-710 cells, whereas splenic effector cells primed with YZ-710 cells exhibited CTL activity against YZ-710 cells, but not against BC-15 cells. Neither group of splenic effector cells showed CTL activity against parental BALB/3T3 cells. These CTL belonged to the CD8+ alphabeta T cell subset. Furthermore, we observed that the CTL activity against t BC-15 cells or YZ-710 cells was blocked with anti-H2-K(d) mAb, but not with anti-H2-D(d) or H2-L(d) mAb. The CTL against BC-15 or YZ-710 cells could kill parental BALB/3T3 cells in the presence of peptides produced by alkali lysis of the LIVAT-BP, suggesting that these CTL indeed recognized the peptide(s) derived from LIVAT-BP. We determined that the epitope for the CTL against BC-15 cells was QYGEGIATEV, corresponding to residues 162-171, and that the epitope recognized by the CTL against YZ-710 cells was GYKLIFRTI, corresponding to residues 123-131 of LIVAT-BP, respectively. Thus, we show here that epitope selection for MHC class I expression is affected by the intracellular localization of the antigenic protein.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • 3T3 Cells
  • Amino Acid Sequence
  • Animals
  • Antigen Presentation / immunology*
  • Bacterial Proteins*
  • Carrier Proteins / immunology*
  • Cytoplasm / ultrastructure
  • Epitopes / immunology*
  • Female
  • H-2 Antigens / genetics*
  • Mice
  • Mice, Inbred BALB C
  • Mitochondria / ultrastructure
  • Molecular Sequence Data
  • T-Lymphocytes, Cytotoxic / immunology
  • T-Lymphocytes, Cytotoxic / ultrastructure*
  • Transfection / genetics

Substances

  • Bacterial Proteins
  • Carrier Proteins
  • Epitopes
  • H-2 Antigens
  • LIVAT-BP protein, Pseudomonas aeruginosa