title: DNA vaccines targeting tumor antigens to B7 molecules on antigen-presenting cells induce protective antitumor immunity and delay onset of HER-2/Neu-driven mammary carcinoma.
abstract: OBJECTIVE
  Presentation of tumor antigens by professional antigen-presenting cells (APC) is critical for the induction of tumor-specific T-cell responses. To facilitate targeted delivery of tumor antigens to APC, we generated DNA vaccines that encode secreted fusion proteins consisting of the extracellular domain of CTLA-4 for binding to costimulatory B7 molecules on APC, fused to residues 1 to 222 of human ErbB2 (HER-2) or a corresponding 224 residues fragment of its rat homologue Neu.
  
  
  METHODS
  Induction of humoral and cellular immune responses and antitumoral activity of the DNA vaccines were tested in murine tumor models with transfected renal carcinoma cells expressing the respective antigens and in transgenic BALB-neuT mice developing spontaneous Neu-driven mammary carcinomas.
  
  
  RESULTS
  Vaccination of BALB/c mice with CTLA-4-ErbB2(222) plasmid DNA markedly improved tumor-free survival on challenge with ErbB2-expressing Renca cells in comparison with untargeted ErbB2(222), accompanied by induction of stronger ErbB2-specific antibody and CTL responses. Likewise, a CTLA-4 vaccine carrying the unrelated NY-ESO-1 cancer-germline antigen was more effective than untargeted NY-ESO-1 in the protection of mice from challenge with NY-ESO-1-expressing tumor cells. Importantly, antitumoral activity of such a CTLA-4 fusion vaccine could be reproduced in immunotolerant BALB-neuT mice, where a corresponding CTLA-4-Neu(224) DNA vaccine markedly delayed the onset of spontaneous Neu-driven mammary carcinomas.
  
  
  CONCLUSIONS
  Our results show that plasmid DNA vaccines for in vivo expression of tumor antigens targeted to APC induce potent immune responses and antitumoral activities, providing a rationale for further development of this approach for specific cancer immunotherapy.
authors.affiliation: Chemotherapeutisches Forschungsinstitut Georg-Speyer-Haus, Frankfurt am Main, Germany.
authors.forename: Arjen
authors.initials: A
authors.lastname: Sloots
authors.forename: Cristina
authors.initials: C
authors.lastname: Mastini
authors.forename: Florian
authors.initials: F
authors.lastname: Rohrbach
authors.forename: Robert
authors.initials: R
authors.lastname: Weth
authors.forename: Claudia
authors.initials: C
authors.lastname: Curcio
authors.forename: Ute
authors.initials: U
authors.lastname: Burkhardt
authors.forename: Elke
authors.initials: E
authors.lastname: Jäger
authors.forename: Guido
authors.initials: G
authors.lastname: Forni
authors.forename: Federica
authors.initials: F
authors.lastname: Cavallo
authors.forename: Winfried S
authors.initials: WS
authors.lastname: Wels
mesh_terms: D000818:Animals; D000938:Antigen-Presenting Cells / Q000276:immunology*; D015703:Antigens, CD / Q000276:immunology; D018122:B7-1 Antigen / Q000276:immunology*; D060908:CTLA-4 Antigen; D005260:Female; D008325:Mammary Neoplasms, Experimental / Q000276:immunology / Q000628:therapy*; D051379:Mice; D008807:Mice, Inbred BALB C; D008822:Mice, Transgenic; D018719:Erb-b2 Receptor Tyrosine Kinases / Q000276:immunology*; D019444:Vaccines, DNA / Q000008:administration & dosage / Q000627:therapeutic use*; D014614:Vaccines, Synthetic / Q000627:therapeutic use*
chemical_list: D015703:Antigens, CD; D018122:B7-1 Antigen; D060908:CTLA-4 Antigen; D018719:Erb-b2 Receptor Tyrosine Kinases; D019444:Vaccines, DNA; D014614:Vaccines, Synthetic; C556706:CTLA4 protein, human; C556707:Ctla4 protein, mouse; C556708:Ctla4 protein, rat