title: Vaccination directed against the human endogenous retrovirus-K (HERV-K) gag protein slows HERV-K gag expressing cell growth in a murine model system.
abstract: BACKGROUND
  Human endogenous retroviruses (HERVs) are remnants of ancestral infections and chromosomally integrated in all cells of an individual, are transmitted only vertically and are defective in viral replication. However enhanced expression of HERV-K accompanied by the emergence of anti-HERV-K-directed immune responses has been observed inter-alia in HIV-infected individuals and tumor patients. Therefore HERV-K might serve as a tumor-specific antigen or even as a constant target for the development of an HIV vaccine.
  
  
  RESULTS
  To verify our hypothesis, we tested the immunogenicity of HERV-K Gag by using a recombinant vaccinia virus (MVA-HKcon) expressing the HERV-K Gag protein and established an animal model to test its vaccination efficacy. Murine renal carcinoma cells (Renca) were genetically altered to express E. coli beta-galactosidase (RLZ cells) and the HERV-K Gag protein (RLZ-HKGag cells). Subcutaneous application of RLZ-HKGag cells into syngenic BALB/c mice resulted in the formation of local tumors in MVA vaccinated mice. MVA-HKcon vaccination reduced the tumor growth. Furthermore, intravenous injection of RLZ-HKGag cells led to the formation of pulmonary metastases. Vaccination of tumor-bearing mice with MVA-HKcon drastically reduced the number of pulmonary RLZ-HKGag tumor nodules compared to vaccination with wild-type MVA.
  
  
  CONCLUSIONS
  The data demonstrate that HERV-K Gag is a useful target for vaccine development and might offer new treatment opportunities for cancer patients.
authors.forename: Benjamin
authors.initials: B
authors.lastname: Kraus
authors.forename: Katrin
authors.initials: K
authors.lastname: Fischer
authors.forename: Katja
authors.initials: K
authors.lastname: Sliva
authors.affiliation: Paul-Ehrlich-Institut, Department of Virology, Paul-Ehrlich-Straße 51-59, Langen 63225, Germany. schba@pei.de.
authors.forename: Barbara S
authors.initials: BS
authors.lastname: Schnierle
mesh_terms: D000818:Animals; D019496:Cancer Vaccines / Q000008:administration & dosage / Q000276:immunology*; D049109:Cell Proliferation; D020077:Endogenous Retroviruses / Q000276:immunology*; D005260:Female; D015683:Gene Products, gag / Q000276:immunology*; D051379:Mice; D009369:Neoplasms / Q000276:immunology; D014611:Vaccination / Q000379:methods*; D014765:Viral Vaccines / Q000008:administration & dosage / Q000276:immunology*
chemical_list: D019496:Cancer Vaccines; D015683:Gene Products, gag; D014765:Viral Vaccines