Despite effective
chemotherapy,
schistosomiasis remains a major public health problem in the developing world, with at least 200 million active
infections resulting in significant morbidity. Rapid
reinfection after treatment, accompanied by extensive residual morbidity, mandates alternative control strategies, including
vaccine development.
Paramyosin, a myofibrillar
protein found only in invertebrates, has been widely studied as a
vaccine candidate for both Schistosoma mansoni and Schistosoma japonicum. Recently, we demonstrated that Th2-biased immune responses to
paramyosin are associated with resistance to
reinfection with S. japonicum in humans; however, challenges in the pilot-scale production of schistosome
paramyosin have hampered further studies of this promising
vaccine candidate. Here we report a method for the pilot-scale expression and purification of recombinant S. japonicum
paramyosin (rSj97). rSj97 was extracted from Escherichia coli inclusion bodies and purified with sequential
anion-exchange,
hydroxyapatite, and size exclusion chromatography. The purified rSj97 was >95% pure as judged by
sodium dodecyl sulfate-
polyacrylamide gel electrophoretic analysis and was free of significant
endotoxin contamination. We demonstrate that, like native
paramyosin, rSj97 adopts an alpha-helical coiled-coil tertiary structure and binds
immunoglobulin and
collagen. Naïve mice infected with S. japonicum produce anti-rSj97
immunoglobulin G (
IgG)
antibodies as early as 4 weeks postinfection, while sera collected from S. japonicum-infected individuals contain anti-rSj97
IgE antibodies. Our method for pilot-scale production of recombinant full-length
paramyosin will facilitate preclinical evaluation of
paramyosin as a
vaccine for
schistosomiasis.