Center for Comparative Medicine and Translational Research, Department of Molecular Biomedical Sciences, College of Veterinary Medicine, North Carolina State University, Raleigh, North Carolina, USA.
Appl Environ Microbiol. 2011 Sep;77(18):6587-96. doi: 10.1128/AEM.05153-11. Epub 2011 Jul 22.
Display of heterologous antigens on the cell surface is considered a useful technique for vaccine delivery by recombinant lactobacilli. In this study, two recombinant Lactobacillus acidophilus derivatives displaying Salmonella flagellin (FliC) were constructed using different anchor motifs. In one instance, the FliC protein was fused to the C-terminal region of a cell envelope proteinase (PrtP) and was bound to the cell wall by electrostatic bonds. In the other case, the same antigen was conjugated to the anchor region of mucus binding protein (Mub) and was covalently associated with the cell wall by an LPXTG motif. These two recombinant L. acidophilus cell surface displays resulted in dissimilar maturation and cytokine production by human myeloid dendritic cells. The surface-associated antigen was highly sensitive to simulated gastric and small intestinal juices. By supplementation with bicarbonate buffer and soybean trypsin inhibitor, the cell surface antigen was protected from proteolytic enzymes during gastric challenge in vitro. The protective reagents also increased the viability of the L. acidophilus cells upon challenge with simulated digestive juices. These results demonstrate the importance of protecting cells and their surface-associated antigens during oral immunization.
在细胞表面展示异源抗原被认为是利用重组乳杆菌进行疫苗传递的一种有用技术。在这项研究中，使用不同的锚定基序构建了两种展示沙门氏菌鞭毛蛋白（FliC）的重组嗜酸乳杆菌衍生物。在一种情况下，FliC 蛋白与细胞周质蛋白酶（PrtP）的 C 末端区域融合，并通过静电键结合到细胞壁上。在另一种情况下，相同的抗原与粘蛋白结合蛋白（Mub）的锚定区域缀合，并通过 LPXTG 基序与细胞壁共价结合。这两种重组嗜酸乳杆菌细胞表面展示导致人髓样树突状细胞的成熟和细胞因子产生不同。表面相关抗原对模拟胃液和小肠液高度敏感。通过补充碳酸氢盐缓冲液和大豆胰蛋白酶抑制剂，在体外进行胃挑战时，细胞表面抗原可免受蛋白水解酶的侵害。保护试剂还增加了在模拟消化液攻击下嗜酸乳杆菌细胞的活力。这些结果表明在口服免疫期间保护细胞及其表面相关抗原的重要性。
