Purification and characterization of a Schistosoma mansoni host-derived enzyme

What is it about?

The paper reports on the purification and characterization of an enzyme previously reported in tegument / detergent extracts of Schistosoma mansoni adult worms that were recovered from infected mice and not found in other extracts of the parasite, although in small amount in extracts of whole adult worms. Interestingly, the enzyme in a detergent extract of adult worms appears similar with an enzyme in mouse blood. Hence, it was described as a host-derived enzyme taken up by the parasite to enable its survival in the blood vessels of mice where it resides. Also previously, the enzyme was observed to display a chymotrypsin-like activity by its ability to hydrolyse the chromogenic substrates (NAPBNE and fast blue salt). However, this report which demonstrates the methods of purification and subsequent analysis by tandem mass spectrometry identified the enzyme as a carboxylesterase (CES). Furthermore, the use of biochemical and immunological techniques as well as bioinformatic tools enabled the characterization of the enzyme as a CES. The uptake of this CES by S. mansoni adult worms from mouse blood could serve useful physiological and immune evasive purposes to enable its survival.

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Why is it important?

The uptake of the enzyme by S. mansoni in mouse could serve several physiological and immune evasive purposes to enhance its survival, such as masking surface antigens to avoid the activation of antibodies, enable easy passage through the blood vessels of mouse where it resides. As the search for alternative drugs or vaccine for schistosomiasis continues, an enzyme such as this that plays important role(s) in parasite establishment and survival in its mammalian hosts could be harnessed as a drug target and/or vaccine candidate to prevent pathology caused by the parasite. The paper demonstrates a simple method of protein purification for identification by mass spectrometry, the use of biochemical and immunological methods as well as bioinformatic tools for protein characterization.