Onchocerca volvulus: Immunolocalization of the extracellular CuZn superoxide dismutase using antibodies raised against a 15-mer epitope of this enzyme

The study describes the immunohistological localization of the extracellula r CuZn superoxide dismutase (SOD2) in the parasitic nematode Onchocerca vol vulus. Using specific antiserum raised against a 15-amino-acid peptide from the N-terminal region of the mature protein, this enzyme is detected prima rily in the intestinal epithelium of the adult worms and to a lesser extent in the muscle cells of the uterine wall. A blocking experiment with the SO D2 peptide reduced the staining significantly, confirming specificity. The localization profile of SOD2 correlates extremely well with the localizatio n of iron deposits in the gut and uterine muscle cells of adult O. volvulus . The detection of SOD2 in the functional intestine of O. volvulus, togethe r with the evidence that it is a secreted protein, indicates that this enzy me in parasitic nematodes is in a position to interact with host molecules. It also demonstrates the accessibility of the the parasite enzyme to an in hibitor or blocking antibody. (C) 1999 Academic Press.