Dash P, Sahoo P K, Gupta P K, Garg L C, Dixit A
Fish Health Management Division, Central Institute of Freshwater Aquaculture, Kausalyaganga, Bhubaneswar 751002, India.
Fish Health Management Division, Central Institute of Freshwater Aquaculture, Kausalyaganga, Bhubaneswar 751002, India.
Fish Shellfish Immunol. 2014 Aug;39(2):512-23. doi: 10.1016/j.fsi.2014.06.007. Epub 2014 Jun 14.
Despite the importance and success of developing a candidate vaccine against Aeromonas hydrophila infection in fish, little is known about the molecular mechanisms of the vaccine-induced immunoprotection in Indian major carp, Labeo rohita, primarily due to lack of information on most of the immune related genes of the species. In this study, a novel candidate antigen recombinant outer membrane protein R (rOmpR) of A. hydrophila was evaluated as a vaccine candidate along with a modified adjuvant formulation. Protective efficacy of the rOmpR immunization was assessed in terms of survival against A. hydrophila challenge as well as modulation of immune response in vaccinated fish after 1, 3, 6, 12, 24, 72 h and 10 days post-injection (using immune gene expression analysis) and 10, 28, 56 and 140 days post-injection (serum immune parameter analysis). The generated immune response was compared with a formalin-killed A. hydrophila antigen preparation using mineral oil only and modified adjuvant alone. We report a variable up-regulation of the immune-related genes viz., lysozyme G, complement factor 4, immunoglobulin M, β2-microglobulin, major histocompatibility complex I and II, and interleukin-1β in anterior kidney and spleen tissues at early time points post-immunization in all the groups, when compared to the control fish. The vaccinated fish also showed an increase in serum natural hemolysin titer, lysozyme and myeloperoxidase activities, and antibody titer irrespective of vaccine formulations as compared to control fish on days 10, 28 and 56. However, the increase in the serum parameters was more pronounced on day 140 in rOmpR-modified adjuvant injected group, indicating the modulatory role of this new vaccine formulation. Upon challenge with live A. hydrophila on days 56 and 140 post-immunization, significantly reduced percent mortality was noted in the group immunized with modified adjuvant based rOmpR vaccine formulation. Taken together, our results suggest that rOmpR along with modified adjuvant could potentially be used as a vaccine formulation to handle A. hydrophila infection on a long-term basis.
尽管开发针对鱼类嗜水气单胞菌感染的候选疫苗具有重要意义且取得了成功，但对于印度主要鲤鱼（印度鲤）中疫苗诱导免疫保护的分子机制却知之甚少，这主要是由于该物种大多数免疫相关基因的信息匮乏。在本研究中，对嗜水气单胞菌的一种新型候选抗原重组外膜蛋白R（rOmpR）以及一种改良佐剂配方进行了疫苗候选评估。通过免疫后1、3、6、12、24、72小时和10天（使用免疫基因表达分析）以及免疫后10、28、56和140天（血清免疫参数分析）时，针对嗜水气单胞菌攻击的存活率以及接种疫苗鱼免疫反应的调节，评估了rOmpR免疫的保护效果。将产生的免疫反应与仅使用矿物油的福尔马林灭活嗜水气单胞菌抗原制剂以及单独的改良佐剂进行了比较。我们报告，与对照鱼相比，在免疫后的早期时间点，所有组的前肾和脾脏组织中免疫相关基因即溶菌酶G、补体因子4、免疫球蛋白M、β2-微球蛋白、主要组织相容性复合体I和II以及白细胞介素-1β均有不同程度的上调。与对照鱼相比，在第10、28和56天，接种疫苗的鱼无论疫苗配方如何，血清天然溶血素滴度、溶菌酶和髓过氧化物酶活性以及抗体滴度均有所增加。然而，在rOmpR-改良佐剂注射组中，血清参数在第140天的增加更为明显，表明这种新疫苗配方的调节作用。在免疫后第56天和140天用活嗜水气单胞菌攻击后，基于改良佐剂的rOmpR疫苗配方免疫组的死亡率显著降低。综上所述，我们的结果表明，rOmpR与改良佐剂一起有可能长期用作应对嗜水气单胞菌感染的疫苗配方。
