Bowden R A, Cloeckaert A, Zygmunt M S, Dubray G
Laboratoire de Pathologie Infectieuse et Immunologie, Institut National de la Recherche Agronomique, Nouzilly, France.
J Med Microbiol. 1998 Jan;47(1):39-48. doi: 10.1099/00222615-47-1-39.
The antibody response specific to the 25-kDa major outer-membrane protein (Omp25) of Brucella melitensis expressed in Escherichia coli was assessed in BALB/c mice. Groups of mice were immunised and boosted either with sonicated E. coli carrying plasmid pAC2533-E. coli (pAC2533)-expressing the gene coding for Omp25 (omp25 gene) of B. melitensis, or with E. coli carrying plasmid pUC19-E. coli (pUC19). One control group received saline. The evolution of antibody responses was investigated by indirect ELISA with whole rough (R) B. melitensis H38 cells as antigen. Serum antibody titres of mice immunised with E. coli (pAC2533) were appreciably higher than those of mice immunised with E. coli (pUC19). The specificity to Omp25 of murine antibodies induced by E. coli (pAC2533) was demonstrated by SDS-PAGE and immunoblotting of five B. melitensis strains. Binding of antibody in E. coli (pAC2533) immune sera to the surface of B. melitensis strains differing in their smooth lipopolysaccharide (S-LPS) expression was also studied by whole-cell ELISA and by flow cytometry. Antibody reactivity to R and smooth-rough (S-R) was much stronger than that to smooth (S) B. melitensis strains, indicating a much better accessibility of Omp25 to antibody on strains lacking or expressing less O-polysaccharide on their surface. The antibodies to Omp25 were predominantly of IgG2a isotype. The capacity of E. coli (pAC2533) to induce protective immune responses against four challenge strains of B. melitensis was further evaluated in mice. Significant reductions in splenic infections, in comparison with mice immunised with E. coli (pUC19) and unimmunised (saline injection) mice, were observed in R B. melitensis B115, S-R B. melitensis EP and S B. melitensis H38 infected mice. Protection against S B. melitensis 16M was not significant. The data from the present study, together with previous results, suggest that humoral immunity against probably conformational, well-exposed epitopes of the Omp25 could contribute to protective mechanisms against B. melitensis infection in mice.
在BALB/c小鼠中评估了对在大肠杆菌中表达的羊种布鲁氏菌25 kDa主要外膜蛋白（Omp25）的特异性抗体反应。将小鼠分组，分别用携带表达羊种布鲁氏菌Omp25编码基因（omp25基因）的质粒pAC2533 - 大肠杆菌（pAC2533）的超声破碎大肠杆菌免疫并加强免疫，或用携带质粒pUC19 - 大肠杆菌（pUC19）的大肠杆菌免疫并加强免疫。一个对照组接受生理盐水。通过以全粗糙（R）羊种布鲁氏菌H38细胞为抗原的间接ELISA研究抗体反应的演变。用大肠杆菌（pAC2533）免疫的小鼠的血清抗体滴度明显高于用大肠杆菌（pUC19）免疫的小鼠。通过对5株羊种布鲁氏菌菌株进行SDS - PAGE和免疫印迹，证明了由大肠杆菌（pAC2533）诱导的鼠抗体对Omp25的特异性。还通过全细胞ELISA和流式细胞术研究了大肠杆菌（pAC2533）免疫血清中的抗体与光滑脂多糖（S - LPS）表达不同的羊种布鲁氏菌菌株表面的结合。抗体对R和光滑 - 粗糙（S - R）菌株的反应性比对光滑（S）羊种布鲁氏菌菌株的反应性强得多，这表明在表面缺乏或表达较少O - 多糖的菌株上，Omp25更容易被抗体识别。针对Omp25的抗体主要是IgG2a同种型。进一步在小鼠中评估了大肠杆菌（pAC2533）诱导针对4株羊种布鲁氏菌攻击菌株的保护性免疫反应的能力。在感染粗糙羊种布鲁氏菌B115、光滑 - 粗糙羊种布鲁氏菌EP和光滑羊种布鲁氏菌H38的小鼠中，与用大肠杆菌（pUC19）免疫的小鼠和未免疫（注射生理盐水）的小鼠相比，脾脏感染明显减少。对光滑羊种布鲁氏菌16M的保护作用不显著。本研究的数据与先前的结果表明，针对Omp25可能的构象性、暴露良好的表位的体液免疫可能有助于小鼠抵抗羊种布鲁氏菌感染的保护机制。
