Expression and Purification of Recombinant ROP1 of Toxoplasma gondii in Bacteria

ABSTRACT

Toxoplasmosis is a worldwide-distributed infection which is mostly asymptomatic but can cause serious health problems in congenitally-infected newborns and immunecompromised individuals. Research is under- going both to improve toxoplasma serological tests, which play the main role in laboratory diagnosis of the infection, and develop an effective vaccine to prevent the infection. Some studies showed usefulness of rhoptry protein 1 [ROP1] antigen of Toxoplasma gondii [T. gondii] in serodiagnosis of the infection and induction of protective immunity. The purpose of this study was to produce recombinant ROP1 and evaluate its antigenicity against human in-fected sera. DNA encoding ROP1, amino acids 171 to 574, was obtained from T. goncff/RH strain by polymerase chain reaction amplification and cloned in probaryotic expression plasmid pET-15b. rROPl was expressed in Escherichia coli [E coli] and purified in a single step by immobilized metal ion affinity chromatography. DNA sequencing showed 99% similarity between the cloned sequence and the corresponding sequence in Gene bank. Results indicated the proper antigenicity of rROPl. Sera from Toxoplasma infected individuals specifically recognized rROPl in Western blotting. rROPl is antigenic toward human infected sera and can be used in studies for development of both a Toxoplasma serological test and a protective vaccine