Enhancement of sindbis virus self-replicating RNA vaccine potency by targeting antigen to endosomal/lysosomal compartments

Hum Gene Ther. 2001 Feb 10;12(3):235-52. doi: 10.1089/10430340150218387.

Abstract

Self-replicating RNA vaccines (RNA replicons) have emerged as an attractive approach for tumor immunotherapy. RNA replicons do not integrate into host chromosomes, eliminating the concern for oncogenicity associated with a DNA vaccine. In this study, we used human papillomavirus type 16 (HPV-16) E7 as a model antigen and evaluated E7-specific immunity generated by a Sindbis virus self-replicating RNA vector, SIN-rep5. Three different constructs were created to target E7 antigen to different cellular localizations: (1) E7, a cytosolic/nuclear protein; (2) Sig/E7, a secretory protein; (3) Sig/E7/LAMP-1, in which we linked the transmembrane and cytoplasmic regions of the lysosome-associated membrane protein 1 (LAMP-1) to E7 protein to target E7 to the endosomal/lysosomal compartment. We found that the RNA replicon vaccine containing the Sig/E7/LAMP-1 fusion gene generated the highest E7-specific T cell-mediated immune responses and antitumor effects relative to RNA vaccines containing either wild-type E7 or Sig/E7. Our in vitro studies demonstrated that E7 antigen from Sig/E7/LAMP-1 RNA replicon-transfected apoptotic cells can be taken up by bone marrow-derived dendritic cells (DCs) and presented more efficiently through the MHC class I pathway than wild-type E7 RNA replicon-transfected apoptotic cells. Furthermore, our data revealed that CD8(+) T cells, CD4(+) T cells, and NK cells were important for the antitumor effects generated by Sig/E7/LAMP-1 RNA vaccination. These results indicate that targeting antigen to the endosomal/lysosomal compartment via fusion to LAMP-1 may greatly enhance the potency of self-replicating RNA vaccines.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Animals
  • Antigens, CD / genetics
  • Apoptosis
  • Bone Marrow Cells / metabolism
  • CD4-Positive T-Lymphocytes / metabolism
  • CD8-Positive T-Lymphocytes / metabolism
  • Cancer Vaccines*
  • Cell Line
  • Cell Membrane / metabolism
  • Cricetinae
  • DNA*
  • Dendritic Cells / metabolism
  • Endosomes / immunology*
  • Enzyme-Linked Immunosorbent Assay
  • Female
  • Flow Cytometry
  • Genes, MHC Class I
  • Humans
  • In Situ Nick-End Labeling
  • Killer Cells, Natural / metabolism
  • Lysosomal Membrane Proteins
  • Lysosomes / immunology*
  • Membrane Glycoproteins / genetics
  • Mice
  • Mice, Inbred C57BL
  • Neoplasms / therapy
  • Oncogene Proteins, Viral / genetics
  • Oncogene Proteins, Viral / immunology
  • Papillomavirus E7 Proteins
  • Phagocytosis
  • Plasmids / metabolism
  • Sindbis Virus / genetics*
  • Spleen / cytology
  • T-Lymphocytes, Cytotoxic / metabolism
  • Time Factors
  • Transfection
  • Vaccines, DNA / immunology*

Substances

  • Antigens, CD
  • Cancer Vaccines
  • Lysosomal Membrane Proteins
  • Membrane Glycoproteins
  • Oncogene Proteins, Viral
  • Papillomavirus E7 Proteins
  • Vaccines, DNA
  • oncogene protein E7, Human papillomavirus type 16
  • DNA