马链球菌马亚种MDMC-0316株主要毒力蛋白Eq5和IdeE2的免疫原性研究OA

This article was aimed to explore the potential of Eq5 and IdeE2 proteins from Streptococcus equi subsp.equi(SEE)strain MDMC-0316 as subunit vaccine targets,the eq5 and ideE2 genes were amplified by PCR,sequenced,fol lowed by immunoinformatic analysis of their corresponding amino acid sequences.The genes were cloned into the pET-28a vector for expression and purification.Purified proteins were used to immunize mice,and antibody titers along with cytokine levels were measured by ELISA.Simulated analysis results showed that both Eq5 and IdeE2 proteins exhibited good immunogenicity and strong stimula-tory effects on IL-2 and IFN-γ production.Immunization of mice with either protein induced high levels of IgG,and the D450nm values of the immune serum antibodies against Eq5 and IdeE2 were both greater than 1.0 at a titer of 1∶51 200.In the Eq5-immunized group,the concentrations of IL-2,IL-4,and IFN-γ were 61.8 pg/mL,105.8 pg/mL,and 151.3 pg/mL,respectively.In the IdeE2-immunized group,the levels were 89.1 pg/mL for IL-2,98.0 pg/mL for IL-4,and 173.5 pg/mL for IFN-γ.Compared with Eq5 protein,IdeE2 protein induced significantly higher production of IL-2 and IFN-γ,which is consistent with the predic-tions from the immunoinformatic analysis.This study provides candidate antigens for the development of a novel subunit vaccine against SEE.