Construction of an Adenovirus Vaccine Expressing the Cross-reactive Antigen AMA1 for Neospora caninum and Toxoplasma gondii and Its Immune Response in an Animal Model

We aimed to construct an adenovirus expressing a cross-reactive fragment of the apical membrane antigen 1 (AMA1) antigen and evaluated the concomitant immune response in BABL/c mice, allowing protection against N. caninum and T. gondii infection.
The study was conducted in Agricultural College of Yanbian University, Yanji, Jilin, China In 2015-2016. Primers were designed using the AMA1 gene sequences of N. caninum (AB265823.1) and T. gondii (AF010264.1). After linearization of the plasmid ADV4-NcAMA1 and the framework plasmid pacAd5, a total of 293T cells were co-transfected and Ad5-NcAMA1 recombinant adenovirus were packed. BALB/c mice were inoculated. Simultaneously serum IgG antibody levels and IFN-γand IL-4 cytokine levels were determined by ELISA. After immunization three times in two weeks, each group of BABL/c mice were divided into two groups, respectively given intraperitoneal inoculation by the Neospora tachyzoite and Toxoplasma tachyzoite. Then we observed the clinical symptoms and statistical survival rate of mice.
The level of IgG in BABL/c mice immunized with Ad5-NcAMA1 was significantly increased when compared with that of pVAX1-NcAMA1 and PBS groups (P The adenovirus vaccineAd5-NcAMA1 could provide protective immunity against N. caninum and T. gondii infection.