布鲁氏菌S2Δbp26缺失株的构建与生物学特性

Construction and biological characterization of Brucella S2Δbp26

摘要:

目的 研发一种安全、有效且可鉴别的新型疫苗。方法 以S2作为亲本株，利用同源重组技术构建S2Δbp26基因缺失株，并对缺失菌株的稳定性、安全性和有效性进行全面评价。结果 构建了S2Δbp26缺失株，该缺失株在体外连续传代20代后其表型和基因型均未发生改变。小鼠和豚鼠的安全性试验结果表明，缺失株在生物安全性方面与S2疫苗株无显著差异。不同代次的S2Δbp26缺失株和S2亲本株接种豚鼠后，每克脾脏分菌数量均小于2×10⁵个，表明该缺失株毒力较低。残余毒力试验数据表明，接种缺失株的小鼠半数痊愈时间比S2亲本株更短。同时，免疫S2Δbp26菌株的小鼠可以成功抵御2×10⁵ CFU/只剂量的M28野毒株攻毒。结论 本研究构建的S2Δbp26基因缺失株展现出优异的安全性和免疫保护力，为布鲁氏菌病可鉴别诊断疫苗的研发提供了技术储备。

关键词:布鲁氏菌;疫苗;S2Δbp26;生物学特性

Abstract:

Objective To develop a safe, effective, and identifiable new vaccine.Methods The gene deletion strain S2Δbp26 was constructed by homologous recombination with S2 as the parental strain. The stability, safety, and efficacy of S2Δbp26 were then evaluated.Results The phenotype and genotype of S2Δbp26 did not change after 20 successive passages in vitro. The experiments in mice and guinea pigs showed that there was no difference in biosafety between S2Δbp26 and S2. The bacterial load was less than 2×10⁵ CFU per gram of spleen in guinea pigs inoculated with S2Δbp26 at different passages and S2, which suggested that the virulence of the mutant strain was attenuated. The mice inoculated with S2ΔBP26 had a shorter 50% recovery time than those inoculated with S2. Meanwhile, the mice immunized with S2Δbp26 could successfully resist the challenge with M28 wild-type strain at a dose of 2×10⁵ CFU/mouse.Conclusion S2Δbp26 was successfully constructed, with excellent safety and immunoprotective capacity, which provided technical reserves for the development of identifiable vaccines for brucellosis.

Key words:Brucella;vaccine;S2Δbp26;biological characterization