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Published on: October 30, 2018
Protective immunity by DNA vaccine against Micropterus salmoides rhabdovirus
Bin Yang1, Zi-Rao Guo1, Zhao Zhao1
1College of Animal Science and Technology, Northwest A&F University, Yangling, China.
Abstract:
Micropterus salmoides rhabdovirus (MSRV) is one of the common pathogens in the largemouth bass industry, which can cause lethal diseases in juvenile fish and enormous economic losses. To establish effective means to prevent MSRV infection, the pcDNA3.1-G plasmid containing the MSRV glycoprotein gene was successfully constructed and intramuscularly injected into the largemouth bass to evaluate the immune responses and protective effects in our study. As the results showed, the serum antibody levels of the fish vaccinated with different doses of pcDNA3.1-G were significantly higher compared with the control groups (PBS and pcDNA3.1). Meanwhile, the immune parameters (acid phosphatase and alkaline phosphatase) were also significantly up-regulated. Several immune-related genes (IgM, IL-8, IL-12p40 and CD40) were expressed in the pcDNA3.1-G groups at higher levels than in the control groups, which indicated that strong immune responses were induced. Besides, the survival percentages of fish in the control groups (PBS and pcDNA3.1) and pcDNA3.1-G groups (2.5, 5, 10 and 20 μg/fish) at 14 days after challenge experiment with MSRV were 0%, 0%, 6.1%, 15.2%, 29.0% and 48.5% respectively. This study indicated that pcDNA3.1-G was a prospective DNA vaccine candidate against MSRV-induced mortality.
Insights
A DNA vaccine using the Micropterus salmoides rhabdovirus (MSRV) glycoprotein gene shows promise for protecting largemouth bass. Vaccination significantly boosted immune responses and increased fish survival rates against MSRV infection.
Area of Science:
- Aquaculture
- Fish immunology
- Vaccine development
Background:
- Micropterus salmoides rhabdovirus (MSRV) causes lethal diseases in juvenile largemouth bass, leading to significant economic losses in the aquaculture industry.
- Effective prevention strategies are crucial for mitigating MSRV-induced mortality and protecting fish stocks.
Purpose of the Study:
- To evaluate the immune responses and protective efficacy of a pcDNA3.1-G plasmid-based DNA vaccine against MSRV in largemouth bass.
- To determine the optimal dosage of the DNA vaccine for inducing robust immunity.
Main Methods:
- Construction of the pcDNA3.1-G plasmid containing the MSRV glycoprotein gene.
- Intramuscular injection of largemouth bass with varying doses of pcDNA3.1-G, PBS, or pcDNA3.1 as controls.
- Assessment of serum antibody levels, immune parameters (acid and alkaline phosphatase), and expression of immune-related genes (IgM, IL-8, IL-12p40, CD40).
- Challenge experiment with MSRV to determine survival rates post-vaccination.
Main Results:
- Vaccination with pcDNA3.1-G significantly increased serum antibody levels and up-regulated immune parameters compared to control groups.
- Expression of key immune-related genes (IgM, IL-8, IL-12p40, CD40) was notably higher in fish vaccinated with pcDNA3.1-G.
- Survival rates after MSRV challenge increased with higher pcDNA3.1-G doses, reaching 48.5% at 20 μg/fish, while control groups showed 0% survival.
Conclusions:
- The pcDNA3.1-G DNA vaccine effectively induces strong immune responses in largemouth bass against MSRV.
- pcDNA3.1-G demonstrates significant potential as a candidate DNA vaccine for preventing MSRV-induced mortality in aquaculture settings.
