United States Department of Agriculture, Agricultural Research Service, Aquatic Animal Health Research Unit, 990 Wire Road, Auburn, AL, 36832-4352, USA.
United States Department of Agriculture, Agricultural Research Service, Aquatic Animal Health Research Unit, 990 Wire Road, Auburn, AL, 36832-4352, USA.
Fish Shellfish Immunol. 2019 Nov;94:308-317. doi: 10.1016/j.fsi.2019.08.071. Epub 2019 Aug 28.
The channel catfish (Ictalurus punctatus) immune response against Ichthyophthirius multifiliis (Ich) after vaccination using plasmid DNA vaccines pcDNA3.1-IAg52a and pcDNA3.1-IAg52b, encoding Ich immobilization antigen genes was studied. Parasite infection level, serum anti-Ich antibodies level, fish mortality after theront challenge, and immune-related gene expression were measured. After in vitro transfection of walking catfish gill cells (G1b) with both pcDNA3.1-IAg52a and pcDNA3.1-IAg52b, antigens IAG52A and IAG52B were detected. During the vaccination trial, 76-fold increase in the Iag52b gene expression was observed in the vaccinated fish group h4 post vaccination. Administration of DNA vaccines by IM injection induced significant gene up-regulation in the head kidney, including immunoglobulin M (IgM), cluster of differentiation 4 (CD4), major histocompatibility I (MHC I), and T cell receptor α (TcR-α) from h4 to d5 post immunization. Fish vaccinated with DNA vaccines or theronts showed increased gene expression of the cytokine interferon (IFN-γ), complement component 3 (C3), and toll-like receptor-1 (TLR-1). Anti-Ich antibodies were detected in fish received pcDNA3.1-IAg52a, pcDNA3.1-IAg52b and the combination of both vaccines d10 post vaccination. Fish vaccinated with pcDNA3.1-IAg52b showed mild parasite infection level, partial survival (20%) and longer mean day to death (MDD) after theront challenge. By contrast, a heavy parasite load, 0% survival and short MDD were observed in the sham vaccinated control fish that received pcDNA3.1 (plasmid without genes encoding Ich immobilization antigen). Further research is needed to improve DNA vaccines for Ich that can induce strong protective immunity in fish. Suggested studies include improved transfection efficiency, use of appropriate adjuvants and including additional parasite antigen genes in the plasmid.
本研究旨在探讨质粒 DNA 疫苗 pcDNA3.1-IAg52a 和 pcDNA3.1-IAg52b （编码 Ich 固定抗原基因）对斑点叉尾鮰（Ictalurus punctatus）针对 Ichthyophthirius multifiliis （Ich）的免疫反应。测量了寄生虫感染水平、血清抗 Ich 抗体水平、经游仆虫挑战后的鱼死亡率以及免疫相关基因的表达。在体外转染行走猫鱼鳃细胞（G1b）后，检测到抗原 IAG52A 和 IAG52B。在疫苗接种试验中，在接种后 h4 时，接种组鱼的 Iag52b 基因表达增加了 76 倍。通过 IM 注射给药 DNA 疫苗诱导了头肾中免疫球蛋白 M（IgM）、分化簇 4（CD4）、主要组织相容性 I（MHC I）和 T 细胞受体 α（TcR-α）的显著基因上调，从 h4 到 d5 免疫后。用 DNA 疫苗或游仆虫接种的鱼显示细胞因子干扰素（IFN-γ）、补体成分 3（C3）和 Toll 样受体 1（TLR-1）的基因表达增加。在接种 pcDNA3.1-IAg52a、pcDNA3.1-IAg52b 和两种疫苗组合后的 d10 检测到抗 Ich 抗体。接种 pcDNA3.1-IAg52b 的鱼显示轻度寄生虫感染水平、部分存活（20%）和游仆虫挑战后平均死亡日（MDD）延长。相比之下，在接受 pcDNA3.1（无编码 Ich 固定抗原基因的质粒）的假疫苗接种对照组中观察到寄生虫负荷重、零存活率和短 MDD。需要进一步研究以提高可在鱼类中诱导强烈保护免疫的 Ich DNA 疫苗。建议的研究包括提高转染效率、使用适当的佐剂以及在质粒中包含其他寄生虫抗原基因。
