Identification of Toxoplasma gondii ROP4 and Enolase2 Proteins as Immunodominant Antigens in Sheep

Toxoplasma gondii is an important intracellular and obligatory protozoan that causes acute and chronic toxoplasmosis in warm-blooded hosts including sheep and humans. This infection can lead to stillbirth among pregnant women and ewes. Identification and detection of Toxoplasma gondii tachyzoites proteins especially antigenic and immunogenic proteins is crucial and essential for producing efficacious and potent drugs and vaccines against toxoplasmosis, and also for introducing efficient diagnostic markers. The aim of this study was to identify the antigenic and immunodominant immunogenic proteins of Toxoplasma gondii in sheep using immunoproteomic techniques.Thirty C57BL/6 mice (male, 5-7 weekly) were selected for providing Toxoplasma gondii tachyzoites. Proteins of tachyzoites were collected using sonication method and the concentration of the proteins was determined by Bradford method. On the other hand, ovine serum containing anti-Toxoplasma gondii antibodies was collected from 10 infected sheep. Then 2-DE-SDS-PAGE electrophoresis, western blotting and immune blotting techniques were carried out. Finally, it was specified and distinguished the spots which belonged to immunogenic and antigenic proteins on the gels, and the proteins were identified by mass spectrometry (MS/MS, MALDI-TOF/MS). The identified two proteins were enolase 2 and rhoptry protein 4 (ROP4).These immunodominant immunogenic and antigenic proteins have potential of being used as markers in serological diagnostic techniques and they may candidate vaccine against Toxoplasma gondii infection.