[Effects of Schistosoma japonicum heat-shock protein 40 on macrophage activation]

To clone and express heat-shock protein 40 gene of Schistosoma japonicum (SjHSP40) and analyze its effect on macrophage activation.

The fragment of gene encoding SjHSP40 was amplified by PCR. The gene was sub-cloned into the prokaryotic expression vector pGEX-6P-1. The recombinant plasmid pGEX-6P-1-SjHSP40 was transformed into E. coli BL21 (DE3) and induced with IPTG. The recombinant protein was purified with Glutathione-Sepharose 4B resin and analyzed by SDS-PAGE and Western-blot. The fusion protein of GST-SjHSP40 was loaded to the macrophage cell-line RAW264.7 for 48 h. Following that, the surface molecules of the macrophages were analyzed by flow cytometry.

DNA sequencing showed that the recombinant plasmid, pGEX-6P-1-SjHSP40, was successfully constructed. The fusion protein of GST-SjHSP40 was induced, purified and specifically recognized by anti-GST antibody. Compared to GST and medium control groups, this fusion protein significantly induced the expression of co-stimulatory molecules (CD40, CD80, and CD86) and MHC-II on the surface of the macrophages.

SjHSP40 significantly up-regulates the expression of co-stimulatory molecules and MHC-II on the surface of the macrophages. These data indicate that SjHSP40 may initiate macrophage activation.