[Evaluating the immunogenicity for plasmid encoding GRA5 antigen of Toxoplasma gondii in BALB/c mice]

ABSTRACT

Severe or lethal damages of toxoplasmosis clearly indicate the need for the development of a more effective vaccine. Immunization with recombinant plasmid encoding protective proteins is a promising vaccination technique. Therefore, this study aimed to evaluate the immunization with plasmid encoding GRA5 antigen of Toxoplasma gondii in BALB/c mice. In this experimental study, three groups of BALB/c mice [n=10 in each group] were selected using simple random sampling. GRA5 gene was cloned into pcDNA3 plasmid and purified by plasmid purification kits and then the product was injected [IM]. To determine the status of cellular and hurnoral immunity, the 11-4, IFN- gamma and IgG; IgG2a, IgG subtypes were evaluated respectively using the ELISA-based assay. The group immunized with pcGRA5 indicated a significant augmented response in humoral and cellular immunity [P mean survival time for the experimental and control groups were 9 and 6 days, respectively. The immunized mice by pcGRA5 produce the higher titers of IFN-gamma indicated a Th1 response which is confirmed by the high level of lgG2a. Findings of this study demonstrate that GRA5 gene of T. gondii can be a potential vaccine candidate against the toxoplasmosis