title: Immune responses in wild-type mice against prion proteins induced using a DNA prime-protein boost strategy.
abstract: OBJECTIVE
  To break immune tolerance to prion (PrP) proteins using DNA vaccines.
  
  
  METHODS
  Four different human prion DNA vaccine candidates were constructed based on the pcDNA3.1 vector: PrP-WT expressing wild-type PrP, Ubiq-PrP expressing PrP fused to ubiquitin, PrP-LII expressing PrP fused to the lysosomal integral membrane protein type II lysosome-targeting signal, and PrP-ER expressing PrP locating the ER. Using a prime-boost strategy, three-doses of DNA vaccine were injected intramuscularly into Balb/c mice, followed by two doses of PrP protein. Two weeks after the last immunization, sera and spleens were collected and PrP-specific humoral and cellular immune responses evaluated by ELISA and ELISPOT tests.
  
  
  RESULTS
  Higher levels of serum PrP antibodies were detected in mice vaccinated using the strategy of DNA priming followed by protein boosting. Of these, WT-PrP, Ubiq-PrP, and PrP-LII induced significantly higher humoral responses. ELISPOT tests showed markedly increased numbers of IFN-γ-secreting T cells in mice vaccinated using the strategy of DNA priming followed by protein boosting after stimulation with recombinant PrP23-90 and PrP23-231. PrP-ER induced the strongest T-cell response.
  
  
  CONCLUSIONS
  Prion vaccines can break tolerance to PrP proteins and induce PrP-specific humoral and cellular immune responses.
authors: State Key Laboratory for Infectious Disease Prevention and Control, National Institute for Viral Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing 102206, China.
authors: YanLing
authors: Y
authors: Han
authors: Yuan
authors: Y
authors: Li
authors: Juan
authors: J
authors: Song
authors: Ying
authors: Y
authors: Wang
authors: Qi
authors: Q
authors: Shi
authors: Cao
authors: C
authors: Chen
authors: BaoYun
authors: B
authors: Zhang
authors: Yan
authors: Y
authors: Guo
authors: ChaoPing
authors: C
authors: Li
authors: Jun
authors: J
authors: Han
authors: XiaoPing
authors: X
authors: Dong
mesh_terms: D000818:Animals; D000906:Antibodies / Q000276:immunology; D016466:CHO Cells; D019556:COS Cells; D002522:Chlorocebus aethiops; D006224:Cricetinae; D003412:Cricetulus; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D006367:HeLa Cells; D006801:Humans; D007108:Immune Tolerance; D007371:Interferon-gamma / Q000276:immunology; D052119:Lysosomal-Associated Membrane Protein 2 / Q000235:genetics / Q000276:immunology; D051379:Mice; D008807:Mice, Inbred BALB C; D010446:Peptide Fragments / Q000276:immunology; D011328:Prions / Q000235:genetics / Q000276:immunology*; D018000:Receptors, Peptide / Q000235:genetics / Q000276:immunology; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000276:immunology; D011994:Recombinant Proteins / Q000276:immunology; D014162:Transfection; D025801:Ubiquitin / Q000235:genetics / Q000276:immunology; D019444:Vaccines, DNA
chemical_list: D000906:Antibodies; C064459:KDEL receptor; D052119:Lysosomal-Associated Membrane Protein 2; D010446:Peptide Fragments; D011328:Prions; D018000:Receptors, Peptide; D011993:Recombinant Fusion Proteins; D011994:Recombinant Proteins; D025801:Ubiquitin; D019444:Vaccines, DNA; C428437:prion protein (23-231); D007371:Interferon-gamma