Action of cyclosporin A on the tapewormsHymenolepis microstoma, H. diminutaandMesocestoides corti in vivo

Abstract

SUMMARYThein vivoactivity of two cyclosporins, cyclosporin A (CsA) and a non-immunosuppressive derivative of dihydrocylosporin A (DHCsA-d) against three tapeworms,Hymenolepis microstoma, H. diminutaandMesocestoides corti, has been assessed. CsA reversibly reduced the dry weight ofH. microstomain the mouse, briefly delayed oviposition and had a statistically significant effect on worm numbers recovered. Oral and subcutaneous treatments of both CsA and DHCsA-d were effective in reducing worm weight; juvenile worms were most susceptible but worms of all ages responded to drug by a dramatic reduction in weight from which they recovered. Multiple courses of CsA were no more active than single courses of treatment but dose response suggested that a threshold level of drug was necessary to evoke activity. By contrast,H. diminutain the rat was completely unaffected by CsA but no explanation for the differences in drug response by these two closely related helminths is forthcoming.Mesocestoides cortiresponded reversibly to CsA in the mouse by a reduction in asexual proliferation of both liver and peritoneal cavity tetrathyridia. The data presented argue in favour of a range of anti-parasitic activities by cyclosporins but the details of the various putative modes of action remain to be defined.