Schistosome vaccine testing: lessons from the baboon model
Mem. Inst. Oswaldo Cruz
; 101(supl.1): 369-372, Oct. 2006. graf
Article
en En
| LILACS
| ID: lil-441277
Biblioteca responsable:
BR1.1
ABSTRACT
The high level of protection elicited in rodents and primates by the radiation-attenuated schistosome vaccine gives hope that a human vaccine relying on equivalent mechanisms is feasible. In humans, a vaccine would be undoubtedly administered to previously or currently infected individuals. We have therefore used the olive baboon to investigate whether vaccine-induced immunity is compromised by a schistosome infection. We showed that neither a preceding infection, terminated by chemotherapy, nor an ongoing chronic infection affected the level of protection. Whilst IgM responses to vaccination or infection were short-lived, IgG responses rose with each successive exposure to the vaccine. Such a rise was obscured by responses to egg deposition in already-infected animals. In human trials it would be necessary to use indirect estimates of infection intensity to determine vaccine efficacy. Using worm burden as the definitive criterion, we demonstrated that the surrogate measures, fecal eggs, and circulating antigens, consistently overestimated protection. Regression analysis of the surrogate parameters on worm burden revealed that the principal reason for overestimation was the threshold sensitivity of the assays. If we extrapolate our findings to human schistosomiasis mansoni, it is clear that more sensitive indirect measures of infection intensity are required for future vaccine trials.
Texto completo:
1
Colección:
01-internacional
Base de datos:
LILACS
Contexto en salud:
3_ND
Problema de salud:
3_helminthiasis
/
3_neglected_diseases
/
3_schistosomiasis
/
3_zoonosis
Asunto principal:
Schistosoma mansoni
/
Esquistosomiasis mansoni
/
Anticuerpos Antihelmínticos
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Vacunas Atenuadas
/
Antígenos Helmínticos
Tipo de estudio:
Prognostic_studies
Límite:
Animals
/
Humans
Idioma:
En
Revista:
Mem Inst Oswaldo Cruz
/
Mem. Inst. Oswaldo Cruz
/
Mem. Inst. Oswaldo Cruz (Online)
/
Memórias do Instituto Oswaldo Cruz (Impresso)
/
Proceedings of the Instituto Oswaldo Cruz
Asunto de la revista:
MEDICINA TROPICAL
/
PARASITOLOGIA
Año:
2006
Tipo del documento:
Article
/
Project document
País de afiliación:
Kenia
/
Reino Unido