Construction And Immunogenicity Assessment Of A Plasmid DNA Encoding Infectious Canine Hepatitis Virus

DNA vaccine is a new generation vaccine emerged in the early of 1990s and it has shown a great potential on the prevention and cure about a wide variety of diseases. DNA vaccine has some characteristics such as eliciting both cellular and humoral immune responses more completely than conventional vaccination and has the advantage of standardization easily. With the development of the promising technology, more and more nucleic acid vaccines, involving the prevention of animal infectious diseases, come into being. Because DNA vaccine seemed to be a promising novel approach for vaccination against canine infectious diseases, the DNA vaccine of pVAX1-CpG-Loop against hepatitis contagiosa canis virus was constructed and the immune efficiency was evaluated. Additionally, the monoclonal antibodies against the Loop of the virus were developed.Hepatitis contagiosa canis was caused by hepatitis contagiosa canis virus, which is called Canine adenovirus (CAV) and belong to one number of adenovirus family. Hepatitis contagiosa canis virus have a powerful pathogenicity and its morphous and structure were studied thoroughly. Canine adenovirus (CAV) distributes worldwide and harm on canine and other fur animal cultivation. CAV was composed 2 different types, CAV-1 and CAV-2. CAV-1, which called ICHV, can cause hepatitis contagiosa canis and bear and fox encephalitis. Loop1 and Loop2 are epitopes of hepatitis contagiosa canis that can make virus neutralization. Loop1 and Loop2 were cloned respectively from hepatitis contagiosa canis virus, the fused gene Loop (Loop1-Loop2) was obtained and cloned into pVAX1-CpG vector. The protein expression of pVAX1-CpG-loop in B16 melanoma cells was detected by Western blot. The immune effiency of pVAX1-CpG-loop in mice was evaluated by ELISA and FACS. We found that vaccination with pVAX1-CpG-loop in mice resulted in both cellular and humoral immune responses were induced in overall mice and the IgG titer in combined immunization group was the highest. pET28a-Loop was constructed , Loop protein and monoclonal antibodies, 2-7F9,2-1B1,which were against Loop and can make virus neutralization, were obtained respectively. These results indicated that the availability of the DNA vaccine and antibodies can provide a technique platform for treatment of hepatitis contagiosa canis.