Immunohistological studies on Onchocerca volvulus paramyosin.

Paramyosin is a muscular protein exclusively found in invertebrate species, which has been proposed as a vaccine candidate against infections with Schistosoma mansoni and Brugia malayi. Here, we report the studies on the distribution of Onchocerca volvulus paramyosin, designated OvPmy, in different O. volvulus stages by immunohistochemistry using rabbit antibodies raised against the recombinant OvPmy protein as well as the induction of the human humoral immune response to OvPmy. To conduct the studies, OvPmy was expressed in Escherichia coli as a fusion protein to raise the rabbit antibodies. The recombinant OvPmy was tested in immunoblots using sera from individuals living in an area hyperendemic for onchocerciasis in Liberia, West Africa. The antibodies used here localised paramyosin exclusively in the muscle tissue of O. volvulus as well as Onchocerca ochengi. No extracellular compartments, such as the cuticle or the lumina of the pseudocoeloma cavity, were labelled; however, labelling was seen in microfilarial fragments taken up by host immune cells, such as giant cells. It was recognised by anti-paramyosin antibodies of a group of onchocerciasis patients.