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Intramuscular injection of plasmid DNA expressing mRNA7 coding the nucleocapsid protein of JHMV partially protected
1Department of Veterinary Radiology, Rakuno Gakuen University, Ebetsu, Japan.
Abstract:
We constructed a plasmid expressing mRNA7 coding the nucleocapsid (N) protein of JHM strain of mouse hepatitis virus (JHMV) under the control of Rous sarcoma virus LTR, referred to as pRSV-mRNA7. When C57BL/6 mice injected intramuscularly (i.m.) with control plasmid DNA which contained no viral sequence were infected with JHMV, necrotic figures of neural cells and diffuse immersion of lymphatic cells in the pedunculus cerebri were observed. In the hypothalamus, vascular cuffing consisting of lymphatic cells was observed. In contrast, no histological change was observed throughout these areas of the brains in the JHMV-infected mice after injection with pRSV-mRNA7. These results showed that the injection with plasmid DNA expressing mRNA7 of JHMV partially protected mice against acute infection with JHMV in the brain. The plasmid DNA was i.m. injected into mice and the cytolytic activity of spleen cells from the mice was assessed by 51Cr-release assay. The spleen cells from the mice administrated with pRSV-mRNA7 showed a significant level of cytolytic activities against the transfected cells expressing the viral N protein even though the spleen cells were not cocultivated with stimulator cells. When the spleen cells from administrated mice with pRSV-mRNA7 were cocultivated with stimulator cells, higher cytolytic activity was observed against the transfected cells, compared with the activity without stimulation.
Insights
DNA vaccination with a plasmid expressing the JHMV nucleocapsid (N) protein protected mice against JHMV-induced brain disease. This approach stimulated spleen cell activity against virus-infected cells.
Area of Science:
- Virology
- Immunology
- Neuroscience
Background:
- Mouse hepatitis virus (JHMV) causes acute brain infections.
- Understanding protective immune responses is crucial for developing JHMV therapies.
Purpose of the Study:
- To evaluate the protective effect of DNA vaccination targeting the JHMV nucleocapsid (N) protein.
- To assess the immune response induced by the DNA vaccine.
Main Methods:
- Constructed a plasmid (pRSV-mRNA7) expressing JHMV N protein mRNA.
- Administered plasmid DNA intramuscularly to C57BL/6 mice.
- Infected mice with JHMV and assessed brain pathology.
- Measured spleen cell cytolytic activity using 51Cr-release assay.
Main Results:
- DNA vaccination with pRSV-mRNA7 significantly reduced JHMV-induced neuropathology.
- Spleen cells from vaccinated mice exhibited significant cytolytic activity against JHMV N protein-expressing cells.
- Vaccination enhanced spleen cell responses, particularly when co-cultured with stimulator cells.
Conclusions:
- DNA vaccine expressing JHMV N protein offers partial protection against JHMV-induced brain infection.
- The vaccine elicits a cell-mediated immune response targeting virus-infected cells.