development of 116 kda fraction for detecting experimental toxoplasma gondii infections in mice.

background: serological diagnosis of toxoplasma gondii infection using crude antigens may not be more accurate. to increase the diagnostic potency of anti-gens, isolation of their immunogenic fractions could be useful. the current re-search adopted to obtain an affinity isolated fraction from rh strain using cnbr sepharose 4b column coupled with infected mice sera helping in detec-tion of igm and igg of toxoplasmosis due to rh strain and other strains.  methods: the isolated fraction was characterized by sds-page. moreover, the diagnostic potency of the fraction was assessed by indirect elisa in mice experimentally infected with rh strain and two other local strains; one of sheep origin and the other of human origin. results: the fraction was found to be consisted of a single band of 116 kda compared with 17 bands ranged from 116 to 16 kda associated with crude ex-tract. the fraction proved potent diagnostic potentials of acute and chronic mice toxoplasmosis. where it was detected both igm and igg antibodies as early as two days and as late as 2 months post experimental infection with any of the three strains. the level of detected igm and igg by rh fraction was higher in mice infected with rh strain than with local strains except igm due to sheep strain parasite. conclusions: the 116 kda fraction of t. gondii tachyzoites can be considered as a candidate in improving of serodiagnosisof toxoplasma infections.