title: Schistosoma mansoni: enhanced efficacy of praziquantel treatment in immune mice.
abstract: Naive CBA/Ca mice and CBA/Ca mice vaccinated 4 weeks previously with radiation-attenuated cercariae of Schistosoma mansoni were challenged with normal cercariae and then treated with 500 mg/kg body weight of Praziquantel (Pzq). The drug was administered intramuscularly or intradermally on day 1, but intramuscularly only on day 6. The results show clearly that in naive mice skin-stage larvae were susceptible to Pzq provided the drug was given intradermally on day 1. Lung worms were susceptible to Pzq given intramuscularly on day 6. Drug efficacy in naive mice is thus dependent upon treatment being given at the correct time and via the optimal route. The efficiency of Pzq treatment was enhanced in vaccinated mice, but was again affected by the treatment regime. Analysis of the data revealed a highly significant synergistic effect between drug treatment and vaccination when Pzq was given intramuscularly on day 6. Synergy was detectable but only marginally significant when the drug was administered intradermally on day 1, and could not be demonstrated when Pzq was given via the intramuscular route on day 1. These findings are discussed in the light of known sites and mechanisms of vaccine resistance in mice, as well as in relation to the mode of action of Pzq against schistosome parasites.
authors.affiliation: Division of Parasitology, National Institute for Medical Research, London, UK.
authors.forename: A
authors.initials: A
authors.lastname: Flisser
authors.forename: V S
authors.initials: VS
authors.lastname: Delgado
authors.forename: D J
authors.initials: DJ
authors.lastname: McLaren
mesh_terms: D000704:Analysis of Variance; D000818:Animals; D005260:Female; D007110:Immunity, Active; D008297:Male; D051379:Mice; D008808:Mice, Inbred CBA; D011223:Praziquantel / Q000008:administration & dosage / Q000627:therapeutic use*; D012550:Schistosoma mansoni / Q000187:drug effects* / Q000276:immunology; D012555:Schistosomiasis mansoni / Q000188:drug therapy* / Q000276:immunology / Q000469:parasitology; D013997:Time Factors; D014611:Vaccination
chemical_list: D011223:Praziquantel