Construction of a fusion gene encoding h1a-spaO of Salmonella paratyphi A and analysis of immuno-protective effects of the recombinant protein
10.3760/cma.j.issn.0254-5101.2014.09.010
- VernacularTitle:甲型副伤寒沙门菌 h1 a-spaO 融合基因构建及其表达产物免疫保护作用
- Author:
Lei JIN
;
Jinqin JIANG
;
Jiaqi FANG
;
Xu′ai LIN
;
Jie YAN
;
Aihua SUN
;
- Publication Type:Journal Article
- Keywords:
Salmonella paratyphi A;
h1a-spaO fusion gene;
Recombinant expression;
Immunoge-nicity;
Immunoprotection
- From:Chinese Journal of Microbiology and Immunology
2014;(9):702-706
- CountryChina
- Language:Chinese
-
Abstract:
Objective To construct a fusion gene (h1a-spaO) encoding H1a-SpaO protein of Sal-monella paratyphi A ( S.paratyphi A) and to express it in prokaryotic expression system , then to further ana-lyze the immunoprotective effects of the expressed protein rH 1a-SpaO.Methods The h1a-spaO fusion gene formed from separate h1a and spaO genes was amplified by PCR using flexible peptide sequence-containing linking primers and then sequenced after T-A cloning.A prokaryotic expression system for expressing h1a-spaO fusion gene was constructed by using the genetic engineering technique .The expressed protein rH1a-SpaO was examined by SDS-PAGE.The antigenicity and immunoreactivity of rH1a-SpaO protein were deter-mined by Western blot assay .The ability of rH1a-SpaO antiserum agglutinating S.paratyphi A strains was detected by micro-Widal′s test.The immunoprotective effects of rH 1a-SpaO against the lethal dose challenge of S.paratyphi A strains were analyzed in a mouse model and that were compared with those by using equal dose of individual recombinant protein H1a and SpaO (rH1a and rSpaO) as the immunogens, respectively. Results The h1a-spaO fusion gene was 100%identical with the individual h1a or spaO gene in nucleotide and amino acid sequences .The constructed prokaryotic expression system could express the recombinant pro-tein rH1a-SpaO with an advantage of high efficiency .rH1a-SpaO protein was able to react with rH 1a or rSpaO antiserum.Moreover, rH1a-SpaO antiserum also could efficiently recognize rH 1a and rSpaO as well as agglutinate Salmonella paratyphi A strains by binding with H-antigen.The immunoprotective rate (93.3%) in mice pre-immunized with 100 μg of rH1a-SpaO protein was significantly higher than that in those pre-immunized with equal dose of rH1a (60.0%) protein or rSpaO protein(53.3%) (P<0.05).Conclusion The recombinant fusion protein rH 1a-SpaO showed more stronger immunoprotective function than the individ-ual rH1a or rSpaO protein , which could be used as an effective antigen for the development of bi -valent para-typhoid A vaccine or typhoid/paratyphoid capsular polysaccharide-protein combined vaccine .
