Kennedy M J, Yancey R J, Sanchez M S, Rzepkowski R A, Kelly S M, Curtiss R
Animal Health Discovery Research, Veterinary Infectious Diseases Section, Pharmacia & Upjohn, Inc., Kalamazoo, Michigan 49001, USA.
Infect Immun. 1999 Sep;67(9):4628-36. doi: 10.1128/IAI.67.9.4628-4636.1999.
Six different isogenic Deltacya Deltacrp derivatives of a strain of Salmonella choleraesuis var. kunzendorf-chi3246 virulent for pigs were constructed by transposon-mediated deletion mutagenesis. These strains were evaluated for virulence and ability to elicit a protective immune response in young weaned pigs after oral administration and were compared to a commercially available vaccine which lacks the 50-kb virulence plasmid (vpl(-)). These derivatives were Deltacya Deltacrp vpl(+), Deltacya Deltacrp vpl(-), Deltacya Delta(crp-cdt) vpl(+), Deltacya Delta(crp-cdt) vpl(-), Deltacya Deltacrp pmi-3834 vpl(+), and Deltacya Delta(crp-cdt) pmi-3834. In experiments to evaluate safety, no significant adverse effects of any of the vaccine constructs were observed, except that two of the strains which carried the virulence plasmid (vpl(+)) caused a small, short-term elevation in maximum temperature compared to pretreatment temperature values. Orally immunized animals, except for those vaccinated with the Deltacya Deltacrp pmi-3834 vpl(+) strain or SC-54, developed significant serum antibody responses 21 days postvaccination as measured by enzyme-linked immunosorbent assay. No cell-mediated immune responses to heat-killed S. choleraesuis were noted at the same time point as measured with heat-killed bacteria as antigen in a lymphocyte proliferation assay. In an oral challenge exposure model with a highly virulent heterologous strain of S. choleraesuis, the Deltacya Deltacrp strains with deletions in pmi were not protective. As measured by morbidity scores, the responses to challenge of the pigs vaccinated with the other four Deltacya Deltacrp derivatives were significantly better than those of the nonvaccinated, challenged group. With the exception of temperature elevation and slight differences in diarrhea scores postchallenge, none of these strains differed significantly from each other in the other clinical parameters analyzed. While the commercial vaccine was protective by most of the parameters measured, it was not fully protective against challenge with virulent S. choleraesuis as judged by diarrhea scores and temperature elevation. Collectively, these data demonstrate that Deltacya Deltacrp derivatives, with or without the virulence plasmid but not with deletions in the pmi gene, are candidates for vaccines for protection against salmonellosis in pigs.
通过转座子介导的缺失诱变构建了猪霍乱沙门氏菌kunzendorf - chi3246毒株的六种不同的同基因Deltacya Deltacrp衍生物，该毒株对猪具有致病性。对这些菌株在口服给药后在幼龄断奶仔猪中的毒力和引发保护性免疫反应的能力进行了评估，并与一种缺乏50 kb毒力质粒（vpl(-)）的市售疫苗进行了比较。这些衍生物分别为Deltacya Deltacrp vpl(+)、Deltacya Deltacrp vpl(-)、Deltacya Delta(crp - cdt) vpl(+)、Deltacya Delta(crp - cdt) vpl(-)、Deltacya Deltacrp pmi - 3834 vpl(+)和Deltacya Delta(crp - cdt) pmi - 3834。在评估安全性的实验中，未观察到任何疫苗构建体有显著的不良反应，只是携带毒力质粒（vpl(+)）的两个菌株与预处理温度值相比，导致最高体温出现了小幅度的短期升高。口服免疫的动物，除了接种Deltacya Deltacrp pmi - 3834 vpl(+)菌株或SC - 54的动物外，在接种疫苗21天后通过酶联免疫吸附测定法检测到显著血清抗体反应。在淋巴细胞增殖试验中，以热灭活的猪霍乱沙门氏菌作为抗原，在同一时间点未观察到对热灭活细菌的细胞介导免疫反应。在一个用高致病性猪霍乱沙门氏菌异源菌株进行口服攻毒暴露模型中，pmi基因有缺失的Deltacya Deltacrp菌株没有保护作用。通过发病率评分衡量，接种其他四种Deltacya Deltacrp衍生物的猪对攻毒的反应明显优于未接种且受到攻毒的组。除了攻毒后体温升高和腹泻评分略有差异外，在分析的其他临床参数中，这些菌株彼此之间没有显著差异。虽然市售疫苗在大多数测量参数上具有保护作用，但根据腹泻评分和体温升高判断，它对高致病性猪霍乱沙门氏菌攻毒并未完全起到保护作用。总体而言，这些数据表明，有或没有毒力质粒但pmi基因无缺失的Deltacya Deltacrp衍生物是预防猪沙门氏菌病疫苗的候选物。
