Molecular and functional characterization of a mortalin-like protein from Schistosoma japonicum (SjMLP/hsp70) as a member of the HSP70 family

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• 作者：Sijie He ; Linlin Yang ; Zhiyue Lv ; Wei Hu ; Jianping Cao ; Jie Wei ; Xi Sun ; Jie Yang ; Huanqin Zheng and Zhongdao Wu
• 刊名：Parasitology Research
• 出版年：2010
• 出版时间：September 2010
• 年：2010
• 卷：107
• 期：4
• 页码：955-966
• 全文大小：646.7 KB

文摘

Schistosomes are the causative agent of schistosomiasis. The 70-kDa heat-shock proteins (HSP70) are considered the predominant HSP family and play a key regulatory role in parasite development and pathogenesis. Based on the published sequences in Genbank/EMBL, an open-reading frame (ORF) encoding 653 amino acids (XP_002581385.1) and belonging to the Schistosoma HSP70 protein family with a molecular weight of 71.49 kDa was identified by bioinformatic analysis. Since the sequence shared 77 % identity with the published full-length Homo sapiens HSP70 protein, it was named Schistosoma mortalin-like protein (MLP/Hsp70). Here, we report the molecular and functional characterization of the Schistosoma japonicum SjMLP/hsp70 as a member of the HSP70 family. The complete SjMLP/hsp70 coding sequence was amplified from a S. japonicum adult worm cDNA library by polymerase chain reaction (PCR) and subcloned into the pET28a expression vector. The purified recombinant protein, rSjMLP/hsp70, was identified as a member of 70-kDa HSP family by mass spectrometry and could be recognized by the S. japonicum-infected mouse serum. Reverse transcriptase polymerase chain reaction (RT-PCR) and western blotting analysis revealed that SjMLP/hsp70 was widely expressed in the eggs, cercariae, schistosomula, and adult worms of S. japonicum. A thermotolerance assay showed that rSjMLP/hsp70 could protect Escherichia coli cells from heat damage. This chaperone-like activity was demonstrated by full-length SjMLP/hsp70. The detection of specific antibody levels by indirect enzyme-linked immunosorbent assay and IFN-γ secretion of splenocytes by ELISpot assay suggested that mice immunized with SjMLP/hsp70 were able to elicit Th1-type bias immune response. The challenge-protective experiment showed that DNA vaccine of SjGST combined with SjMLP/hsp70 could induce a 31.31 % reduction of worm burden and 58.59 % reduction of egg burden in intestinal tissue of immunized mice. Our results imply that SjMLP/hsp70 has a potential adjuvant function and might be a vaccine candidate for schistosomiaisis, which is the first report of the expression and preliminary characterization analysis of this molecule.