Chuang Shu-Chun, Huang Wan-Ling, Kau Sau-Wei, Yang Yun-Pei, Yang Chung-Da
Department of Physiology, College of Medicine, Kaohsiung Medical University, No. 100, Shih-Chuan 1st Road, Kaohsiung 807, Taiwan.
Graduate Institute of Animal Vaccine Technology, National Pingtung University of Science and Technology, No. 1, Shuefu Road, Neipu, Pingtung 912, Taiwan.
Vaccines (Basel). 2014 May 14;2(2):380-96. doi: 10.3390/vaccines2020380.
Outer membrane proteins, such as glyceraldehyde-3-phosphate dehydrogenase (GAPDH), are considered immunodominant antigens for eliciting protective immunity against Vibrio harveyi, the main etiological agent of vibriosis in fish. Cationic antimicrobial peptides (AMPs), such as pleurocidin (PLE), play important roles in activating and recruiting immune cells, thereby contributing to subsequent innate and adaptive immune responses. In the present study, we aimed to use PLE peptide as a potent adjuvant to improve the immunogenicity of V. harveyi recombinant GAPDH (rGAPDH). In order to prepare a controlled-release vaccine, PLE peptide and rGAPDH protein were simultaneously encapsulated into polymeric microparticles made from the biodegradable poly(lactide-co-glycolide) (PLG) polymer. The resulting PLG-encapsulated PLE plus rGAPDH (PLG-PLE/rGAPDH) microparticles, 3.21-6.27 μm in diameter, showed 72%-83% entrapment efficiency and durably released both PLE and rGAPDH for a long 30-day period. Following peritoneal immunization in grouper (Epinephelus coioides), PLG-PLE/rGAPDH microparticles resulted in significantly higher (p < 0.05, nested design) long-lasting GAPDH-specific immunity (serum titers and lymphocyte proliferation) than PLG-encapsulated rGAPDH (PLG-rGAPDH) microparticles. After an experimental challenge of V. harveyi, PLG-PLE/rGAPDH microparticles conferred a high survival rate (85%), which was significantly higher (p < 0.05, chi-square test) than that induced by PLG-rGAPDH microparticles (67%). In conclusion, PLE peptide exhibits an efficacious adjuvant effect to elicit not only improved immunity, but also enhanced protection against V. harveyi in grouper induced by rGAPDH protein encapsulated in PLG microparticles.
外膜蛋白，如甘油醛-3-磷酸脱氢酶（GAPDH），被认为是引发针对哈维氏弧菌（鱼类弧菌病的主要病原体）的保护性免疫的免疫显性抗原。阳离子抗菌肽（AMPs），如杀鲇素（PLE），在激活和招募免疫细胞方面发挥重要作用，从而促进随后的先天免疫和适应性免疫反应。在本研究中，我们旨在使用PLE肽作为强效佐剂来提高哈维氏弧菌重组GAPDH（rGAPDH）的免疫原性。为了制备控释疫苗，将PLE肽和rGAPDH蛋白同时封装到由可生物降解的聚（丙交酯-共-乙交酯）（PLG）聚合物制成的聚合物微粒中。所得直径为3.21 - 6.27μm的PLG包裹的PLE加rGAPDH（PLG-PLE/rGAPDH）微粒显示出72% - 83%的包封效率，并在长达30天的时间内持续释放PLE和rGAPDH。在石斑鱼（斜带石斑鱼）腹腔免疫后，PLG-PLE/rGAPDH微粒产生的GAPDH特异性免疫（血清滴度和淋巴细胞增殖）显著高于（p < 0.05，嵌套设计）PLG包裹的rGAPDH（PLG-rGAPDH）微粒，且持续时间更长。在对哈维氏弧菌进行实验性攻击后，PLG-PLE/rGAPDH微粒赋予了较高的存活率（85%），这显著高于（p < 0.05，卡方检验）PLG-rGAPDH微粒诱导的存活率（67%）。总之，PLE肽表现出有效的佐剂作用，不仅能提高免疫，还能增强由PLG微粒包裹的rGAPDH蛋白诱导的石斑鱼对哈维氏弧菌的保护作用。
