Abstract:Objective:To clone and express the rhoptry protein 18(ROP18) from tachyzoites of the RH strain of T.gondii and establish methods to determine and locate the expression of ROP18 in T.gondii. Methods: The gene fragment of ROP18 was amplified by PCR from the cDNA of T.gondii RH strain and cloned into pET-28a(+) vector. The recombinant ROP18 was expressed in E.coil Rosetta strain and purified by cutting the gel slices with KCl stain. AntiROP18 polyclonal antibody was produced in rabbit. The ROP18 in T.gondii was determined and located by Western blotting and indirect immunofluorescence assay (IFA) respectively. Results: The recombinant and its polyclonal antibody were obtained. The specific band of ROP18 in T.gondii was detected using polyclonal antibody by Western blotting. The ROP18 was distributed in the rhoptry of T.gondii by IFA. Conclusion: Western blotting and IFA could detect and locate ROP18 expression using anti-ROP18 polyclonal antibody. It will facilitate the study of the biological functions of ROPs.