Toxoplasmosis is an important zoonotic disease caused by that can infect almost all warm-blooded animals worldwide, including humans. The high prevalence of infection and its ability to cause serious harm to humans and animals, especially immunodeficient individuals, make it a key public health issue. Accurate diagnostic tools with high sensitivity are needed for controlling infection. In the current study, we compared the performance of recombinant SAG2, GRA6, and GRA7 in ELISA for the serological diagnosis of infection in cats. We further investigated the antigenicity of recombinant dense granule protein 3 (rGRA3), rGRA5, rGRA8, and rSRS29A expressed in a plant-based, cell-free expression system for detecting antibodies in -infected cats. In summary, our data suggest that GRA7 is more sensitive than the other two antigens for the serodiagnosis of infection in cats, and GRA3 expressed in the cell-free system is also a priming antigen in serological tests for detecting infection in cats.