title: [Escherichia coli heat-labile enterotoxin B subunit enhances the immune response against canine parvovirus VP2 in mice immunized by VP2 DNA vaccine].
abstract: OBJECTIVE
  To investigate the effect of Escherichia coli heat-labile enterotoxin (LT) B subunit (LTB) gene on canine parvovirus (CPV) VP2 gene vaccine.
  
  
  METHODS
  The LTB gene was amplified by PCR from genomic DNA of E. coli 44815 strain. The VP2-70 fragment (210 bp) encoding major epitope of VP2 (70 amino acids) was amplified by PCR from a plasmid encoding VP2 gene. VP2-70 and LTB genes were inserted into the eukaryotic vector to construct VP2-70 gene,LTB gene and VP2-70-LTB fused gene vectors. The mice were immunized with VP2-70 vector, VP2-70-LTB fused vector, or VP2-70 vector plus LTB vector, respectively. The antibody titers at the different time were measured by using ELISA method. The spleen lymphocyte proliferation activity was analyzed by 3-(4, 5-Dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide (MTT) assay.
  
  
  RESULTS
  The sequence of VP2-70 and LTB genes was identified. The recombinant VP2-70 and LTB proteins could be expressed in HEK293T cells in a secretory manner. The mice immunized with VP2-70 vector, VP2-70-LTB vector or VP2-70 vector plus LTB vector could generate the specific antibody against VP2 protein. The antibody titer immunized with VP2-70-LTB vector reached 1:5120 at 35 d post immunization, significantly higher than that of other two groups (P < 0.01). For antibody isotype analysis, the IgG1 isotype antibody titers in all test groups were significantly higher than of IgG2a (P < 0.01). The high-level spleen lymphocyte stimulation index was observed in the three test groups under the stimulation with Con A, higher than that in control groups (P < 0.01).
  
  
  CONCLUSIONS
  LTB gene could enhance the humoral immune response of CPV VP2 gene vaccine in mice.
authors.affiliation: Department of Basic Veterinary Medicine, College of Animal Science and Technology, Agricultural University of Hebei, Baoding 071001, China. dongmeiyuqi@yahoo.com.cn
authors.forename: Dongmei
authors.initials: D
authors.lastname: Han
authors.forename: Fei
authors.initials: F
authors.lastname: Zhong
authors.forename: Xiujin
authors.initials: X
authors.lastname: Li
authors.forename: Wei
authors.initials: W
authors.lastname: Wang
authors.forename: Xingxing
authors.initials: X
authors.lastname: Wang
authors.forename: Sumin
authors.initials: S
authors.lastname: Pan
mesh_terms: D000818:Animals; D001427:Bacterial Toxins / Q000235:genetics / Q000276:immunology*; D036022:Capsid Proteins / Q000008:administration & dosage / Q000235:genetics / Q000276:immunology*; D004283:Dog Diseases / Q000276:immunology* / Q000517:prevention & control / Q000821:virology; D004285:Dogs; D004768:Enterotoxins / Q000235:genetics / Q000276:immunology*; D029968:Escherichia coli Proteins / Q000235:genetics / Q000276:immunology*; D007114:Immunization; D051379:Mice; D010322:Parvoviridae Infections / Q000276:immunology / Q000517:prevention & control / Q000662:veterinary* / Q000821:virology; D017993:Parvovirus, Canine / Q000276:immunology*; D011993:Recombinant Fusion Proteins / Q000008:administration & dosage / Q000235:genetics / Q000276:immunology; D014765:Viral Vaccines / Q000008:administration & dosage / Q000235:genetics / Q000276:immunology*
chemical_list: D001427:Bacterial Toxins; D036022:Capsid Proteins; D004768:Enterotoxins; D029968:Escherichia coli Proteins; D011993:Recombinant Fusion Proteins; D014765:Viral Vaccines; C027538:heat-labile enterotoxin, E coli