副猪嗜血杆菌血清4、13和14型TbpA对豚鼠的交互免疫保护性

Protective effects of Haemophilus parasuis serotype 4, 13 and 14 TbpA on cross-immunity in guinea pigs

【背景】副猪嗜血杆菌(Haemophilusparasuis,HPS)是猪革拉瑟氏病(Gl?sser?sdisease)的病原体,目前在对该病的防控中,由于长期使用抗生素产生的耐药性以及灭活疫苗缺乏交互免疫保护力,亟待寻求新的方法来解决这一问题。【目的】探究不同血清型HPS转铁结合蛋白A(TbpA)对豚鼠的交互免疫保护性,为进一步用仔猪开展相关研究奠定基础。【方法】采用HPS血清型4、13和14型重组TbpA以0.1mg/只、经2次间隔期为20d的免疫后,检测豚鼠血清IgG抗体和细胞因子(IL-2、IL-5、IL-8、IFN-γ、MCP-1、TNF-α)水平;以HPS血清型4、13和14型菌株5 LD50剂量腹腔攻毒,检查病理组织学变化及其免疫保护率。【结果】HPS血清型4、13和14型重组TbpA均能诱导豚鼠产生较高水平的特异性抗体IgG,并使细胞因子显著升高。HPS血清型4、13和14型重组TbpA在免疫后均能对豚鼠产生交互免疫保护,其中HPS血清型13型TbpA免疫组的交互免疫保护率最高,对血清型4、14型HPS均为50.0%,对相同血清型HPS的免疫保护率也最高,达到83.3%,病理组织学检查显示与HPS血清型4、14型TbpA免疫组相比,13型TbpA免疫组的组织切片病理变化与攻毒对照组之间差异更明显。【结论】HPS血清型4、13和14型TbpA均能诱导豚鼠的体液免疫和相关细胞因子的分泌,产生交互免疫保护力,其中HPS血清型13型Tbp A的交互免疫保护力最强,可作为一种新的疫苗候选抗原。

[Background] Haemophilus parasuis(HPS) is the pathogen of Gl?sser?s disease. Currently in the prevention and control of the disease, due to antibiotic resistance and the lack of cross-immunity protection of inactivated vaccines, new methods are urgently needed to solve this problem. [Objective] The aim of this study was to explore the cross-immunoprotective properties of different serotype HPS transferrin-binding protein A(TbpA) in guinea pigs for further research in piglets. [Methods] Recombinant TbpA of HPS serotypes 4, 13 and 14 were immunized at 0.1 mg with 20-day interval and then detected the serum antibody(IgG) and cytokines(IL-2, IL-5, IL-8, IFN-γ, MCP-1 and TNF-α) by ELISA. HPS-BZ, HPS-LJ3 and HPS-SZ strains were dosed at 5 LD50 by intraperitoneal injection. Then, the pathological changes and immune protection rate were examined. [Results] Recombinant TbpA of HPS serotypes 4, 13 and 14 could induce high levels of antibody(IgG) and cytokines, and provide cross-immunity protection to guinea pigs. Among them, the HPS serotype 13 TbpA immunization group had the highest cross-immunity protection rate, both serotype 4 and 14 HPS were 50.0%, and the highest immune protection rate against the same serotype HPS was 83.3%. The pathological examination showed that compared with HPS serotype 4 and 14 TbpA immunization group, the difference between the pathological changes of HPS serotype 13 TbpA immunization group and the challenge control group was more significant. [Conclusion] Recombinant TbpA of HPS serotypes 4, 13 and 14 can induce the humoral and cellular immune responses in guinea pigs, among which HPS serotype 13 TbpA has the strongest cross-immunity protection and can be used as a new vaccine candidate antigen.