RESUMEN
Scientists, for a variety of reasons, need to carry out in vivo research. Since experiments that require the use of adult animals pose various logistical, economical and ethical issues, the use of embryonic and larval forms of some organisms are potentially attractive alternatives. Early life stages are appealing because, in general, large numbers of individuals can be maintained in relatively simple housing, minimising costs, and their use involves fewer legal formalities. With this succinct review, we aim to provide an overview of different biological issues that have been successfully explored with the help of eggs, embryos and larvae from the frog, zebrafish and chicken.
Asunto(s)
Modelos Animales , Proyectos de Investigación , Animales , Embrión de Pollo/citología , Embrión de Pollo/fisiología , Pollos/fisiología , Embrión no Mamífero/citología , Embrión no Mamífero/fisiología , Femenino , Salud , Vivienda para Animales , Humanos , Larva/citología , Larva/crecimiento & desarrollo , Larva/fisiología , Modelos Biológicos , Óvulo/citología , Óvulo/fisiología , Reproducción , Retina/citología , Retina/fisiología , Ciencia/métodos , Especificidad de la Especie , Pez Cebra/embriología , Pez Cebra/fisiologíaRESUMEN
BACKGROUND: Parasitic worms induce a strong, polarized T(H)2-type immune response. The kinetics of gastrointestinal nematode-induced T(H)2-type responses, especially in the context of primary infection, have been extensively studied in experimental infection models but not in human subjects. OBJECTIVE: We sought to determine the kinetics of basophil sensitization in subjects infected with Necator americanus during the first 12 weeks after infection. METHODS: Thirty nonasthmatic subjects with allergic rhinoconjunctivitis were randomized in a double-blind manner to cutaneous administration of either 10 hookworm infective larvae or histamine placebo. Blood samples were taken at regular intervals for 12 weeks, and basophil activation was determined in whole blood by measuring CD63 and CD203c levels on stimulation with N americanus excretions/secretions. Parasite-specific immunoglobulin responses were assessed by means of ELISA and Western blotting. RESULTS: Median values reflecting basophil activation (CD203c/CD63 double-positive cells) in the excretion/secretion-stimulated infected group steadily increased after week 4, consistently achieving statistical significance compared with the placebo group between 6 and 12 weeks after infection. Only parasite-specific IgM levels increased significantly during this period, whereas total and parasite-specific IgE levels did not differ between groups. CONCLUSION: Basophils are sensitized early in the context of a low-dose primary infection with N americanus in the absence of measurable total and specific IgE serum level increase.