POPLINE Document Number: 141255
Author(s):
Hagen HE
Klager SL
Williams GT
Source citation:
Tropical Medicine and International Health, 1998 Dec;3(12):945-50.
Abstract:
While the blackflies' innate immune system is unable to encapsulate and melanize intruding parasites, blackflies are nonetheless capable of killing and clearing Onchocerca microfilariae. Using the bovine species Onchocerca ochengi as a model for human onchocerciasis, the authors have been investigating the immune response of Simulium damnosum s.l., the main vector of human onchocerciasis in sub-Saharan Africa. The parasite is naturally transmitted by S. damnosum s.l. and occurs throughout the cattle-breeding areas of Africa. This study explored how to kill Onchocerca parasites inside the vector and the hypothesis that apoptosis is one of the main causes of death among Onchocerca parasites in the vector insect. The injection of female S. damnosum s.l. with 5 microfilariae of noncryopreserved microfilariae of O. ochengi and the protease inhibitors z-VAD.fmk and boc-D.fmk led to significantly increased survival of the parasites. Subsequent in situ apoptosis detection assays demonstrated that in the case of boc-D.fmk, enhanced survival was due to a diminished apoptosis level of the microfilariae in vivo. Additional assays using O. ochengi microfilariae coinjected with serine protease inhibitors into S. damnosum s.l. revealed that certain serine protease inhibitors can reduce the level of apoptosis. Study findings clearly demonstrate that apoptosis is involved in eliminating Onchocerca parasites in blackflies.
Keywords:
United KingdomIndex page
Research Report
Onchocerciasis
Immunity
Developed Countries
Europe, Western
Europe
Parasitic Diseases
Diseases
Immune System
Physiology
Biology