Previous or ongoing schistosome infections do not compromise the efficacy of the attenuated cercaria vaccine

T M Kariuki, G J Van Dam, A M Deelder, I O Farah, D S Yole, R A Wilson, P S Coulson

Research output: Contribution to journalArticlepeer-review

Abstract

A current or previous schistosome infection might compromise the efficacy of a schistosome vaccine administered to humans. We have therefore investigated the influence of infection on vaccination, using the baboon as the model host and irradiated Schistosoma mansoni cercariae as the vaccine. Protection, determined from worm burdens in test and controls, was not diminished when vaccination was superimposed on a chronic infection, nor was it diminished when it followed a primary infection terminated by chemotherapy. Protection was also assessed indirectly based on fecal egg output and circulating antigen levels, as would be the case in human vaccine trials. In almost all instances, these methods overestimated protection, sometimes with discrepancies of > 20%. The overwhelming immune response to egg deposition in infected animals made it difficult to discern a contribution from vaccination. Nevertheless, the well-documented immunomodulation of immune responses that follows egg deposition did not appear to impede the protective mechanisms elicited by vaccination with attenuated cercariae.

Original languageEnglish
Pages (from-to)3979-3986
Number of pages8
JournalInfection and Immunity
Volume74
Issue number7
DOIs
Publication statusPublished - Jul 2006

Keywords

  • CIRCULATING ANODIC ANTIGEN
  • BABOON PAPIO-ANUBIS
  • IMMUNE-RESPONSES
  • PROTECTIVE IMMUNITY
  • MANSONI INFECTION
  • RESISTANCE
  • EXPOSURES
  • PROTEOME
  • SENEGAL
  • SINGLE

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