The present invention disclosed a pharmaceutical composition for treating Toxoplasma gondii infection comprising novel plant-derived chimeric antibodies. Besides, the present invention also disclosed a method of producing the novel plant-derived chimeric antibodies. The plant-derived chimeric antibodies can be generated rapidly from a phage display antibody library and expressed in plants as a cost-effective antibody production platform. These novel plant-derived chimeric antibodies are suitable for the development of plant-derived immunotherapeutic interventions against toxoplasmosis.