Doggett T A, Jagusztyn-Krynicka E K, Curtiss R
Department of Biology, Washington University, St. Louis, Missouri 63130.
Infect Immun. 1993 May;61(5):1859-66. doi: 10.1128/iai.61.5.1859-1866.1993.
In this study, we used a vaccine strain of Salmonella typhimurium to express antigenic determinants of the SpaA antigen of Streptococcus sobrinus, which is involved in the caries-forming process. We cloned either a single repeat (pYA2901) or three tandem repeats (pYA2905) of the 0.48-kb fragment of the spaA gene, which codes for an important component of the SpaA protein, plus a 1.2-kb minor antigenic determinant and measured the resulting immune responses to SpaA in orally immunized BALB/c mice. The single or triple repeat of the spaA gene fragment was inserted into the Asd+ vector pYA292 and was transformed into the S. typhimurium delta cya delta crp vaccine strain chi 4072 containing delta asd in the chromosome. Female BALB/c mice were then orally immunized with two doses of the S. typhimurium containing either of the two SpaA constructs, and the immune responses to the expressed SpaA protein were assessed. Significant serum immunoglobulin G (IgG) anti-SpaA titers were detected in mice immunized with chi 4072(pYA2905) but not chi 4072(pYA2901). Salivary anti-SpaA IgA titers were minimal and were only detected in mice immunized with S. typhimurium expressing the SpaA encoded by pYA2905. Intestinal anti-SpaA IgA titers, however, were detected in both groups of mice, particularly in mice immunized with chi 4072(pYA2905). An oral booster 26 weeks after the initial series of immunizations resulted in increased serum IgG titers in both chi 4072(pYA2901)- and chi 4072(pYA2905)-immunized animals, particularly in the chi 4072(pYA2905)-immunized animals. No anamnestic IgA response was detected in the saliva following the booster immunization.
在本研究中，我们使用鼠伤寒沙门氏菌疫苗株来表达参与龋齿形成过程的远缘链球菌SpaA抗原的抗原决定簇。我们克隆了spaA基因0.48 kb片段的单个重复序列（pYA2901）或三个串联重复序列（pYA2905），该片段编码SpaA蛋白的一个重要组分，外加一个1.2 kb的次要抗原决定簇，并检测了经口服免疫的BALB/c小鼠对SpaA产生的免疫反应。将spaA基因片段的单个或三个重复序列插入Asd+载体pYA292，并转化到染色体中含有Δasd的鼠伤寒沙门氏菌ΔcyaΔcrp疫苗株chi 4072中。然后用含有两种SpaA构建体之一的鼠伤寒沙门氏菌对雌性BALB/c小鼠进行两剂口服免疫，并评估对表达的SpaA蛋白的免疫反应。在用chi 4072（pYA2905）免疫的小鼠中检测到了显著的血清抗SpaA免疫球蛋白G（IgG）滴度，但在用chi 4072（pYA2901）免疫的小鼠中未检测到。唾液抗SpaA IgA滴度极低，仅在免疫了表达由pYA2905编码的SpaA的鼠伤寒沙门氏菌的小鼠中检测到。然而，在两组小鼠中均检测到肠道抗SpaA IgA滴度，尤其是在用chi 4072（pYA2905）免疫的小鼠中。在初次免疫系列26周后进行口服加强免疫，导致在chi 4072（pYA2901）免疫和chi 4072（pYA2905）免疫的动物中血清IgG滴度均升高，尤其是在chi 4072（pYA2905）免疫的动物中。加强免疫后在唾液中未检测到回忆性IgA反应。
