RESUMO
The limitations associated with the use of anthelmintic drugs in the control of gastrotintestinal nematodosis, such as the emergence of anthelmintic resistance, have stimulated the study of the immunological control of many parasites. In the case of Haemonchus contortus, several vaccination trials using native and recombinant antigens have been conducted. A group of antigens with demonstrated immunoprotective value are cathepsin B - like proteolytic enzymes of the cysteine proteinase type. These enzymes, which have been observed in both excretory-secretory products and somatic extracts of H. contortus, may vary among different geographic isolates and on strains isolated from different hosts, or even from the same host, as has been demonstrated in some comparative studies of genetic variability. In the present study, we evaluated the genetic variability of the worms that fully developed their endogenous cycle in immunised sheep and goat in order to identify the alleles of most immunoprotective value. To address these objectives, groups of sheep and goats were immunised with PBS soluble fractions enriched for cysteine proteinases from adult worms of H. contortus from either a strain of H. contortus isolated from goats of Gran Canaria Island (SP) or a strain isolated from sheep of North America (NA). The results confirmed the immunoprophylactic value of this type of enzyme against haemonchosis in both sheep and goats in association with increased levels of specific IgG. The genetic analysis demonstrated that the immunisation had a genetic selection on proteinase-encoding genes. In all the immunised animals, allelic frequencies were statistically different from those observed in non-immunised control animals in the four analysed genes. The reduction in the allelic frequencies suggests that parasites expressing these proteases are selectively targeted by the vaccine, and hence they should be considered in any subunit vaccine approach to control haemonchosis in small ruminants.
Assuntos
Cisteína Proteases/genética , Cisteína Proteases/imunologia , Haemonchus/enzimologia , Haemonchus/genética , Alelos , Animais , Anticorpos Anti-Helmínticos/análise , Antígenos/genética , Antígenos/farmacologia , Sequência de Bases , Catepsina B/farmacologia , DNA de Helmintos/genética , DNA Espaçador Ribossômico/genética , Feminino , Frequência do Gene , Variação Genética , Doenças das Cabras/sangue , Doenças das Cabras/imunologia , Doenças das Cabras/parasitologia , Cabras , Hemoncose/sangue , Hemoncose/imunologia , Hemoncose/prevenção & controle , Hemoncose/veterinária , Haemonchus/imunologia , Masculino , Polimorfismo Conformacional de Fita Simples , Vacinas Protozoárias/química , Vacinas Protozoárias/isolamento & purificação , Ovinos , Doenças dos Ovinos/sangue , Doenças dos Ovinos/imunologia , Doenças dos Ovinos/parasitologiaRESUMO
A preliminary analysis of the significance of genetic diversity in cysteine proteinase genes has been performed simultaneously in sheep and goats, with regard to the immunological control using these enzymes against haemonchosis. For this purpose, we have studied the cross-immunoprotective effect of cysteine protease-enriched protein fractions (CPFs) in adult worms of two Haemonchus contortus strains from North America and Spain that are adapted to sheep and goats, respectively. Previous genetic analysis of cysteine proteinase genes in both strains has shown that some of loci are polymorphic and these differences are translated into changes in the amino acid sequences. However, our results show that CPFs from H. contortus adult worms have a protective effect against the parasite in both sheep and goats. These results are similar regardless of whether they were obtained from sheep or goat-adapted H. contortus strains, which could be very important in case H. contortus CPFs were commercially used in different countries, as vaccines to prevent the negative effects of this parasite. Interestingly, this experimental inoculation of both species with a heterologous strain of H. contortus contributes to the idea shown in previous studies about how difficult is the interpretation and the comparison of vaccination where strains not adapted to a specific host are used. Therefore, the challenger of using heterologous strains could provide similar results to those observed in immunised animals. This study suggests the possibility of exploring the mechanisms involved in natural protection against non-adapted strains, in order to develop strategies to control haemonchosis.
Assuntos
Cisteína Proteases/metabolismo , Doenças das Cabras/parasitologia , Hemoncose/veterinária , Haemonchus/enzimologia , Doenças dos Ovinos/parasitologia , Animais , Ácidos Cicloexanocarboxílicos/sangue , Fezes/parasitologia , Regulação Enzimológica da Expressão Gênica , Variação Genética , Doenças das Cabras/sangue , Cabras , Hemoncose/sangue , Hemoncose/parasitologia , Masculino , Contagem de Ovos de Parasitas , Ovinos , Doenças dos Ovinos/sangueRESUMO
La trombocitopenia inducida por heparina se presenta con relativa frecuencia en el escenario clinico, en especial en el subgrupo de pacientes con enfermedad cardiovascular. En los ultimos años se han caracterizado los eventos involucrados en su fisiopatologia y se han desarrollado nuevas tecnicas para el diagnostico de laboratorio, todo esto orientado a lograr un diagnostico precoz y un manejo adecuado de esta patologia. La mejor estrategia terapeutica aun esta. por definir ya que hasta el momento no existe ningun anticoagulante ideal que pueda ser utilizado como alternativa a la heparina en pacientes con trombocitopenia inducida por heparina aunque recientemente se han utilizado con exito los inhibidores directos de la trombina. Se presenta una revision de los aspectos clinicos, de diagnostico y tratamiento de la trombocitopenia inducida por heparina, hacienda énfasis en el programado para cirugia cardiaca