MOLECULAR CHARACTERIZATION AND LOCALIZATION OF AN ONCHOCERCA-VOLVULUSPI-CLASS GLUTATHIONE-S-TRANSFERASE

Glutathione S-transferases (GSTs) constitute a major mechanism in helm inth organisms and are regarded vaccine candidates against helminth in fections. Onchocerca volvulus glutathione-binding proteins were purifi ed from the aqueous soluble fraction of homogenised adult females by a ffinity chromatography on glutathione-agarose. The eluted proteins had a specific GST activity of 1.6 mu mol min(-1) mg(-1). Immunohistochem ical studies localised these antigens in the hypodermis, the wall of t he seminal receptacle and spermatozoa of adult worms. A lambda gt11 cl one was isolated from an expression library of O. volvulus by immunosc reening. Sequence analysis revealed that it encoded a pi-class GST wit h 60% identity with Caenorhabditis elegans and up to 45% identity with mammalian pi-class GSTs. Antibodies affinity selected with recombinan t GST demonstrated cross-reactivity between Litomosoides sigmodontis a nd O. volvulus GSTs.