Increased antigen presentation efficiency by coupling antigens to MHC class I trafficking signals

J Immunol. 2008 Jan 1;180(1):309-18. doi: 10.4049/jimmunol.180.1.309.


Genetic modification of vaccines by linking the Ag to lysosomal or endosomal targeting signals has been used to route Ags into MHC class II processing compartments for improvement of CD4+ T cell responses. We report in this study that combining an N-terminal leader peptide with an MHC class I trafficking signal (MITD) attached to the C terminus of the Ag strongly improves the presentation of MHC class I and class II epitopes in human and murine dendritic cells (DCs). Such chimeric fusion proteins display a maturation state-dependent subcellular distribution pattern in immature and mature DCs, mimicking the dynamic trafficking properties of MHC molecules. T cell response analysis in vitro and in mice immunized with DCs transfected with Ag-encoding RNA showed that MITD fusion proteins have a profoundly higher stimulatory capacity than wild-type controls. This results in efficient expansion of Ag-specific CD8+ and CD4+ T cells and improved effector functions. We used CMVpp65 and NY-ESO-1 Ags to study preformed immune responses in CMV-seropositive individuals and cancer patients. We show that linking these Ags to the MITD trafficking signal allows simultaneous, polyepitopic expansion of CD8+ and CD4+ T cells, resulting in distinct CD8+ T cell specificities and a surprisingly broad and variable Ag-specific CD4+ repertoire in different individuals.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Animals
  • Antigen Presentation*
  • Antigens / genetics
  • Antigens / immunology
  • Antigens / metabolism*
  • Antigens, Neoplasm / genetics
  • Antigens, Neoplasm / immunology
  • Antigens, Neoplasm / metabolism
  • CD4-Positive T-Lymphocytes / immunology
  • CD8-Positive T-Lymphocytes / immunology
  • Dendritic Cells / immunology
  • Dendritic Cells / transplantation
  • Epitopes / immunology
  • Histocompatibility Antigens Class I / genetics
  • Histocompatibility Antigens Class I / immunology
  • Histocompatibility Antigens Class I / metabolism*
  • Humans
  • Membrane Proteins / genetics
  • Membrane Proteins / immunology
  • Membrane Proteins / metabolism
  • Mice
  • Mice, Inbred Strains
  • Molecular Sequence Data
  • Phosphoproteins / genetics
  • Phosphoproteins / immunology
  • Phosphoproteins / metabolism
  • Protein Sorting Signals* / genetics
  • Protein Transport
  • Recombinant Fusion Proteins / genetics
  • Recombinant Fusion Proteins / immunology
  • Recombinant Fusion Proteins / metabolism*
  • Transfection
  • Vaccination*
  • Viral Matrix Proteins / genetics
  • Viral Matrix Proteins / immunology
  • Viral Matrix Proteins / metabolism


  • Antigens
  • Antigens, Neoplasm
  • CTAG1B protein, human
  • Epitopes
  • Histocompatibility Antigens Class I
  • Membrane Proteins
  • Phosphoproteins
  • Protein Sorting Signals
  • Recombinant Fusion Proteins
  • Viral Matrix Proteins
  • cytomegalovirus matrix protein 65kDa