production of mag1 antigen of toxoplasma gondii in escherichia coli

introduction : toxoplasmosis is a parasitic infection caused by the protozoan toxoplasma gondii it leads to serious medical problems in congenitally-infected and immunocompromised individuals, while it is quite harmless in immunocompetent individuals. toxoplasma tissue cyst matrix protein (mag1) induces early humoral and cell-mediated immune responses. previous studies suggested recombinant mag1 as a promising antigen for serodiagnosis of toxoplasma infection. a dna fragment encoding mag1, comprising amino acids 50 to 207, was amplified from t . gondii rh strain and cloned in prokaryotic expression plasmid pet-15b(+). the cloned dna fragment was sequenced and showed 100% similarity with the published sequences available in genbank database. recombinant mag1 was expressed in escherichia coli, and was highly purified in a single step by immobilized metal ion affinity chromatography. in western blot analysis, purified protein showed a much stronger reactivity with sera from patients with acute toxoplasma infection, compared to those with chronic infection. mag1 protein, in combination with other acute-phase markers might be useful in discriminating acute/reactivated toxoplasma infections from chronic forms. j med microbiol infec dis, 2014, 1 (2): 5 pages.