Construction of eukaryotic expression plasmid encoding Fba protein of group A streptococcus and elicitation of immune responses by it / 中国免疫学杂志

ABSTRACT

Objective:To construct eukaryotic expression plasmid ecording a novel surface protein Fba of GAS, and to explore its impact on host immune responses.Methods:Fba gene was amplified by PCR using strain SSI-9 (GAS M1 serotype isolates) as the template, then cloned into pcDNA3.1 for constructing eukaryotic expression plasmid pcDNA3.1/fba and sequenced. Female CD1 mice were randomly individed into 6 groups, and immunized respectively with Fba protein, M protein, pcDNA3.1/fba + Fba protein, pcDNA3.1/fba, pcDNA3.1 and PBS as control. Blood was obtained from the mice and specific antibody of IgG was detected by ELISA. Spleen cells were assessed with lymphocyte proliferation assays.CD4+T cell and CD8+T cell were detected by flow cytometry (FCM). Assay results were analyzed with SPSS10.0.Results:The IgG against Fba protein kept hightest levels in group immunized with Fba protein. The levels of lymphocyte proliferation, CD4+, CD8+T cell were significantly high in the group pcDNA3.1/fba. Conclusion:(1) Just as M protein, the antibody to Fba protein could be efficiently induced by immunization with Fba protein, which showed that Fba protein was hopefully to be a candidate protein for vaccine against GAS.(2) Eukaryotic expression plasmid pcDNA3.1/fba was successfully constructed and this recombinant plasmid could efficiently induce antibody and CD4+ T cell for againsting GAS.