Prediction results of Th cell epitopes of TgIMP1.

<div><p><i>Toxoplasma gondii</i> (<i>T</i>. <i>gondii</i>) is widely spread around the world, which can cause serious harm to immunosuppressed patients. Currently, the commercial test kits are poor at assessing <i>T</i>. <i>gondii</i> infection and vaccine effectiveness, making an urgent need to exploit effective enzyme-linked immunosorbent assay with great performance to compensate for this deficiency. Here, the TgIMP1 recombinant protein was expressed in <i>E</i>. <i>coli</i> BL(21) cells. The TgIMP1 was purified with affinity chromatography and the reactivity was retained with anti-TgIMP1 antibodies. The TgIMP1 was then used to develop an indirect ELISA (IMP1-iELISA) and the reaction conditions of IMP1-iELISA were optimized. As a result, the cut-off value was determined to be 0.2833 by analyzing the OD<sub>450nm</sub> values of forty <i>T</i>. <i>gondii</i>-negative sera. The coefficient of variation of 6 <i>T</i>. <i>gondii</i>-positive sera within and between runs were both less than 10%. The IMP1-iELISA was non-cross-reactive with the sera of cytomegalovirus, herpes virus, rubella virus, <i>Cryptosporidium</i> spp., <i>Theileria</i> spp., <i>Neospora</i> spp. and <i>Plasmodium</i> spp.. Furthermore, the sensitivity and specificity of IMP1-iELISA were 98.9% and 96.7%, respectively, based on testing 150 serum samples. The results suggest that this IMP1-iELISA is specific, sensitive, repeatable and can be applied to the detection of T. gondii infections in the medical and health industries.</p></div>