Abstract: Objective  To screen the host cell proteins that can interact with Toxoplasma gondii ROP18 by using yeast two-Hybrid system.  Methods  The ROP18 gene fragments were amplified by RT-PCR from mRNA of T. gondii RH strain. The product of RT-PCR was digested with double restriction enzyme and was subcloned into the bait vector pGBKT7. The recombinant plasmid was transferred into yeast AH109 strain. Its toxicity and the autonomous activating activity were tested. The human fetal brain cDNA library was screened with pGBKT7-ROP1825-251aa as the bait plasmid by yeast two-hybrid system.  Results  The bait was constructed and AH109/PGBKT7-ROP18 showed an autonomous activity. The yeast strain AH109/pGBKT7-ROP1825-251aa line was then mated with the Mate & PlateTM Human Fetal Brain cDNA library. Using the selection procedures， eight novel host cell proteins were obtained： damage-specific DNA binding protein 1（DDB1）， torsin A interacting protein 1（TOR1AIP1）， integrin beta 1， solute carrier family 3 （SLC3A2）， tyrosylprotein sulfotransferase（TPST2）， OCIA domain containing 1（OCIAD1）， Der1-like domain family member 2（DERL2）, in addition to Homo sapiens activating transcription factor 6 beta（ATF6）.  Conclusion  Eight novel host cell proteins have been obtained via yeast two-hybrid system, which can interact with TgROP18.

Key words:  , Toxoplasma gondii；ROP1825-251aa；Yeast two-hybrid；Interaction；Host protein