title: Enhancement of sindbis virus self-replicating RNA vaccine potency by targeting antigen to endosomal/lysosomal compartments.
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.
authors.affiliation: Department of Pathology, Johns Hopkins Medical Institutions, Baltimore, MD 21205, USA.
authors.forename: W F
authors.initials: WF
authors.lastname: Cheng
authors.forename: C F
authors.initials: CF
authors.lastname: Hung
authors.forename: K F
authors.initials: KF
authors.lastname: Hsu
authors.forename: C Y
authors.initials: CY
authors.lastname: Chai
authors.forename: L
authors.initials: L
authors.lastname: He
authors.forename: M
authors.initials: M
authors.lastname: Ling
authors.forename: L A
authors.initials: LA
authors.lastname: Slater
authors.forename: R B
authors.initials: RB
authors.lastname: Roden
authors.forename: T C
authors.initials: TC
authors.lastname: Wu
mesh_terms: D000818:Animals; D015703:Antigens, CD / Q000235:genetics; D017209:Apoptosis; D001854:Bone Marrow Cells / Q000378:metabolism; D015496:CD4-Positive T-Lymphocytes / Q000378:metabolism; D018414:CD8-Positive T-Lymphocytes / Q000378:metabolism; D019496:Cancer Vaccines; D002460:Cell Line; D002462:Cell Membrane / Q000378:metabolism; D006224:Cricetinae; D004247:DNA; D003713:Dendritic Cells / Q000378:metabolism; D011992:Endosomes / Q000276:immunology*; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D005434:Flow Cytometry; D005805:Genes, MHC Class I; D006801:Humans; D020287:In Situ Nick-End Labeling; D007694:Killer Cells, Natural / Q000378:metabolism; D051907:Lysosomal Membrane Proteins; D008247:Lysosomes / Q000276:immunology*; D008562:Membrane Glycoproteins / Q000235:genetics; D051379:Mice; D008810:Mice, Inbred C57BL; D009369:Neoplasms / Q000628:therapy; D009856:Oncogene Proteins, Viral / Q000235:genetics / Q000276:immunology; D050725:Papillomavirus E7 Proteins; D010587:Phagocytosis; D010957:Plasmids / Q000378:metabolism; D012845:Sindbis Virus / Q000235:genetics*; D013154:Spleen / Q000166:cytology; D013602:T-Lymphocytes, Cytotoxic / Q000378:metabolism; D013997:Time Factors; D014162:Transfection; D019444:Vaccines, DNA / Q000276:immunology*
chemical_list: D015703:Antigens, CD; D019496:Cancer Vaccines; D051907:Lysosomal Membrane Proteins; D008562:Membrane Glycoproteins; D009856:Oncogene Proteins, Viral; D050725:Papillomavirus E7 Proteins; D019444:Vaccines, DNA; C059731:oncogene protein E7, Human papillomavirus type 16; D004247:DNA