Determination of antigenic properties of VirB9, a protein of type Ⅳ secretion system of Brucella
10.3760/cma.j.issn.2095-4255.2013.03.007
- VernacularTitle:布鲁杆菌Ⅳ型分泌系统蛋白VirB9免疫原性检测
- Author:
Jin-ming, FAN
;
Fa-xing, WANG
;
Bo, ZHANG
;
Ling, JIANG
;
Bei, LI
- Publication Type:Journal Article
- Keywords:
Brucella;
Type Ⅳ secretion system;
Immunogenicity;
Vaccine
- From:Chinese Journal of Endemiology
2013;(3):263-266
- CountryChina
- Language:Chinese
-
Abstract:
Objective To detect the immunogenicity of VirB9,a protein of type Ⅳ secretion system of Brucella.Methods Full length VirB9 gene was cloned into plasmid pET32a and expressed in Escherichia (E.) coli BL21 (DE3).Expression of recombinant protein was induced by isopropyl beta-D-thiogalactopyranoside (IPTG) and the recombinant fusion protein was purified by affinity chromatography on Ni2+-conjugated chelateing sepharose.The purity of the purified protein was ascertained by sodium dodecyl sulfate polyacrylamide gel electrophoresis(SDSPAGE) and the concentration was measured by bicinchoninic acid (BCA) protein assay kit.Animal model was established by immunizing BAL B/c mice with live vaccine strain S19 of Brucella and the mice immunized with phosphate buffered saline (PBS) as control.The blood of immunized mice was acquired after 4 weeks.Antibody against VirB9 in S19 immunized mice was detected by Rose Bengal plate agglutination test and serum tube agglutination test; IgG antibody titers against VirB9 in immunized mice were determined by enzyme linked immunosorbent assay(ELISA).At the 35th day,the immunized mice and control mice were killed and spleens were collected.The splenocytes were harvested and stimulated with each of VirB9,concanvalin A(ConA) or medium in triplicate.Production of gamma interferon (IFN-γ) was determined by enzyme-linked immunospot assay (Elispot).Results The full length of VirB9 gene was cloned into pET32a.The recombinant VirB9 protein was expressed at 43 × 103 in relative molecular mass and the purity of the purified recombinant VirB9 protein was above 97％ in SDS-PAGE and the concentration was 1.6 g/L in BCA protein assay.The antibody of VirB9 was detected in all S19 immunized mice but not PBS immunized mice by Rose Bengal plate agglutination test.The antibody titer in all S19 immunized mice was ＞ 1 ∶ 800 or ＞ 1 ∶ 3200 by tube agglutination test and ELISA,respectively.Meanwhile,the protein stimulated stronger IFN-γresponse in immunized mice than that in the control mice(147 cells Vs 38 cells).Conclusion VirB9 can stimulate humoral and cellular immunity and it might be an appropriate target for developing subunit vaccine against Brucella.
