Assessment of combined therapy of recombinant glutathione S-transferase 26 and praziquantel on immunoparasitological responses

Abstract

The present work was undertaken to improve the efficacy of praziquantel (PZQ, CAS 55268-74-1, EMBAY 8440) by its combination with the anti-fecundity vaccine, recombinant glutathione S-transferase 26 (rSm GST26). Five groups of mice were used. One group received multiple doses of rSm GST26 (1 microgram x 4) 2 days apart starting 7 days before infection. The second group received PZQ (2 x 500 mg/kg) 8 weeks post infection. The third group received combined therapy of PZQ and multiple rSm GST26 in the same doses and at the same previously mentioned timings. Infected untreated and multiple bacterial lysate treated groups served as respective controls. All animals from all groups were sacrificed 10 and 12 weeks post infection. Hepatic histopathology granuloma diameter, liver functions, parasitological and immunological parameters were studied. Multiple injections of rSm GST26 alone decreased worm count, number of eggs per female worm, viability of eggs, granuloma diameter and accelerated the ova destruction. Treatment with PZQ alone induced incomplete eradication of worms, moderate reduction in granuloma diameter, decreased number of ova per g tissue and normalized the liver function. Combined therapy with rSmGST26 and PZQ showed dual effects as evident by the complete eradication of worms, pronounced reduction in the number of ova per g tissue, acceleration of egg destruction, marked reduction in granuloma diameter and amelioration of egg-induced pathology with increase in anti-GST immunoglobulin G.