RESUMO
Immunofluorescence on live Dictyocaulus viviparus parasites revealed a significant antibody response by vaccinated and patently infected bovine hosts to the sheath of infective larvae (L3), a structure which is generally thought to be shed from the parasite surface prior to invasion of host tissue. In contrast, surface-exposed antigens of the adult, egg and pulmonary L1 stages were recognized only by serum antibody from calves exposed to a patient lungworm infection. Radioiodination of sheathed L3 identified a restricted set of components while a more complex pattern of labelled material was observed with adult parasites. Many more components of adult worms were labelled by the Bolton-Hunter than by the Iodogen reagent, probably reflecting the more penetrative labelling propensities of the former. Stage-specificity of surface-associated antigens of adult parasites was demonstrated by their immunoprecipitation by antibody from patently-infected, but not from vaccinated, calves. There was no in vitro release of the major iodinatable surface-associated antigens of adult parasites not any binding of antibody raised against adult excretory-secretory (ES) products to the surface of living adult worms, suggesting that surface components do not contribute to adult ES products in this species. Antibody responses to the surface of adults, L1 and eggs were specific to patently-infected animals and may provide a useful indicator of exposure to patent infection.
Assuntos
Antígenos de Helmintos/imunologia , Antígenos de Superfície/análise , Doenças dos Bovinos/imunologia , Infecções por Dictyocaulus/imunologia , Dictyocaulus/imunologia , Pneumopatias Parasitárias/veterinária , Animais , Anticorpos Anti-Helmínticos/imunologia , Bovinos , Doenças dos Bovinos/prevenção & controle , Dictyocaulus/crescimento & desenvolvimento , Dictyocaulus/efeitos da radiação , Eletroforese em Gel de Poliacrilamida , Feminino , Imunofluorescência , Cobaias , Pneumopatias Parasitárias/imunologia , Pneumopatias Parasitárias/prevenção & controle , Coelhos , Vacinação/veterináriaRESUMO
In the lungworm-endemic areas of Kashmir, 6-10 week old lambs of Karnah and Kashmir Merino breeds were vaccinated with two doses of 50 kR gamma-irradiated larvae of Dictyocaulus filaria, given a month apart. Assessed on the basis of reduced prevalence and significantly lower faecal larval output over an eight-month observation period, vaccinated lambs showed a high degree of resistance to naturally acquired D. filaria infection. The results also show that vaccination against D. filaria provided some degree of protection against infection with other lungworm species.
