Characterization of TsDAF-21/HSP90 protein from the parasitic nematode Trichinella spiralis

The Tsdaf-21 cDNA was cloned into pET-32a and subsequently expressed in Escherichia coli. The recombinant protein TsDAF-21 was purified and evaluated as an antigen in Western blot. The serum from mouse 14, 21, and 28 days after being infected with Trichinella spiralis recognized rTsDAF-21, but the serum from mouse 7 days post infection of T. spiralis could not react with rTsDAF-21. It implied that the antibody of TsDAF-21 did appear in the host 14 days after infection of T. spiralis. Western blot analysis revealed that the expression of TsDAF-21 in the muscle larvae incubated at room temperature for 8 h and at 37 °C for 4 and 8 h was increased compared to the muscle larvae incubated at 4 °C for 4 and 8 h. The results imply that the expression of TsDAF-21 could be induced at high temperature, not by the cold stress. The expression of TsDAF-21 could be attenuated under the different concentrations of geldanamycin (GA) treatment. Western blot showed that the expression of TsDAF-21 was reduced in the muscle larvae of T. spiralis treated with GA compared to Ampicillin and Gentamycin sulfate treated as control, and this inhibition effect was GA dependent. Other antibiotic treatments did not show any inhibition effects. Immunolocalization showed that TsDAF-21 was expressed in the different stages of T. spiralis including newborn larvae, muscle larvae, and adult worms. TsDAF-21 was mostly localized in nuclei of the cells in the worm. These results suggest that the expression of TsDAF-21 could be induced by the heat stress and attenuated by GA treatment, and TsDAF-21 might be a diagnostic marker for Trichinellosis.