Evaluation Of The Immune Response Elicited By Multi-antigenic DNA Vaccine Expressing SAG1, ROP2 And GRA2 Against Toxoplasma Gondii

The parasite Toxoplasma gondii can infect most mammals and birds,sometimes causing severe pathology.Previous studies have reported that multi-antigenic vaccines were more effective than single-antigenic vaccine.It was also reported that the a single-gene vaccine with SAG1 or ROP2,GRA2 could only produce partial protection against Toxoplasma gondii.In this study,we constructed a multi-antigenic DNA vaccine containing SAG1,ROP2 and GRA2,and evaluated its immune response.We used IL-12 as an adjuvant to enhance the immune response.We immunized BALB/c mice intramuscularly.After immunization,we evaluated the immune response using lymphocyte proliferation assay,cytokine and antibody measurements.The results showed that the group immunized with pcDNA3.1-SAG1-ROP2-GRA2 produced high Th1 immune response compared to other groups immunized with double-gene plasmid,empty plasmid or phosphate buffered saline,respectively.Moreover,the co-immunization with IL-12 genes enhanced the immune response significantly and prolonged survival time.The current study showed that multi-antigenic DNA with IL-12 produced potent,effective and long-term protection against T.gondii challenge.