Schistosoma mansoni is one of Digenea that infect human causing chronic
debilitating disease, schistomiasis. Although S. mansoni adults are living in
the blood stream (inferior mesenteric venous system), the cut section of
these vessels with living worms show no obvious immunological (inflammatory
cells) or hematological (clot) attack around parasites. It was hypothesized
that tegumental surface of schistosomes express proteins modulating
the local environment around them, preventing host defense response.
Here we have expressed an active schistosoma tegumental alkaline phosphatase
(SmAP) in Chinese hamster ovary (CHO). SmAP is a ~60 kDa
ecto-nucleotidase metalloenzyme- need divalent ions for fully efficiency at
pH 9. . We previously reported that living worms can cleave exogenous
adenosine monophosphate (AMP) to generate adenosine acting as a local
anti-inflammatory mediator. We show here that rSmAP can cleave AMP to
generate adenosine. In addition, it can catalyse nucleoside monophsphate
(CMP, GMP, and TMP) using the products as nutrients. Also, we show that
live schistosomes as well as rSmAP can cleave sphingosine-1-phosphate
(S1P) - lipid mediator released by platelet regulates lymphocyte trafficking,
and control platelet aggregationThis is the first demonstration of any pathogen
cleaving this key control molecule. This work reveals that the worms
using its tegumental SmAP to make less hostile surrounding area.