Single-walled carbon nanotubes enhance the immune protective effect of a bath subunit vaccine for pearl gentian grouper against Iridovirus of Taiwan.

Iridovirus of Taiwan (TGIV) has been threatening the grouper farming since 1997, effective prophylaxis method is urgently needed. Subunit vaccine was proved to be useful to against the virus. Bath is the simplest method of vaccination and easy to be administrated without any stress to fish. In this research, we constructed a prokaryotic expression vector of TGIV's major capsid protein (MCP) to acquire the vaccine. Single-walled carbon nanotubes (SWCNTs) were used as the carrier to enhance the protective effect of bath vaccination for juvenile pearl gentian grouper (bath with concentrations of 5, 10, 20 mg/L for 6 h). Virus challenge was done after 28 days. Survival rates were calculated after 14 days. The level of antibody, activities of related enzymes in serums and expression of immune-related genes in kidneys and spleens were test. The results showed that vaccine with SWCNTs as carrier induced a higher level of antibody than that without. In addition, the activities of related enzymes (acid phosphatase, alkaline phosphatase, superoxide dismutase) and the expression of immune-related genes (Mx1, IgM, TNFαF, Lysozyme, CC chemokine 1, IL1-ß, IL-8) had a significantly increase. What's more, higher survival rates (42.10%, 77.77%, 89.47%) were provided by vaccine with SWCNTs than vaccine without SWCNTs (29.41%, 38.09%, 43.75%). This study suggests that the protective effect of vaccine that against TGIV with the method of bath vaccination could be enhanced by SWCNTs and SWCNTs could be a potential carrier for other subunit vaccines.

Immune response and protective effect against spring viremia of carp virus induced by intramuscular vaccination with a SWCNTs-DNA vaccine encoding matrix protein.

To elicit the immune protective of vaccine against the highly contagious and pathogenic disease caused by spring viremia of carp virus (SVCV), a novel functionalized single-walled carbon nanotubes (SWCNTs) were applied as a delivery vehicle for DNA vaccine. In this study, we report a SWCNTs-DNA vaccine encoding matrix protein of SVCV which, when injected in the muscle at a dose of 10 µg SWCNTs-pcDNA-M vaccine, confers up to 51.3% protection against intraperitoneal challenge with SVCV. In addition, SWCNTs as a promising vehicle can enhance about 17.5% of the immune protective effect in SWCNTs-pcDNA-M vaccinated common carp compared with fish injected with naked pcDNA-M DNA vaccine. In addition, serum antibody production, none specific immunity parameters (complement activity, superoxide dismutase activity (SOD), acid phosphatase activity (ACP) and alkaline phosphatase activity (AKP)) and immune-related genes were used to verify the enhancement immune response induced in SWCNTs-pcDNA-M vaccinated fish, herein all these mentioned immune activities were significantly enhanced after immunization. Thereby, it is revealed that the M gene of SVCV could be used as an antigen for DNA vaccine constructs, and SWCNTs could be a candidate DNA vaccine carrier to enhance the immunological response against fish disease.