RESUMEN
BACKGROUND: During the last two decades research on animal filarial parasites, especially Onchocerca ochengi, infecting cattle in savanna areas of Africa revealed that O. ochengi as an animal model has biological features that are similar to those of O. volvulus, the aetiological agent of human onchocerciasis. There is, however, a paucity of biochemical, immunological and pathological data for O. ochengi. Galectins can be generated by parasites and their hosts. They are multifunctional molecules affecting the interaction between filarial parasites and their mammalian hosts including immune responses. This study characterized O. ochengi galectin, verified its immunologenicity and established its immune reactivity and that of Onchocerca volvulus galectin. RESULTS: The phylogenetic analysis showed the high degree of identity between the identified O. ochengi and the O. volvulus galectin-1 (ß-galactoside-binding protein-1) consisting only in one exchange of alanine for serine. O. ochengi galectin induced IgG antibodies during 28 days after immunization of Wistar rats. IgG from O. ochengi-infected cattle and O. volvulus-infected humans cross-reacted with the corresponding galectins. Under the applied experimental conditions in a cell proliferation test, O. ochengi galectin failed to significantly stimulate peripheral blood mononuclear cells (PBMCs) from O. ochengi-infected cattle, regardless of their parasite load. CONCLUSION: An O. ochengi galectin gene was identified and the recombinantly expressed protein was immunogenic. IgG from Onchocerca-infected humans and cattle showed similar cross-reaction with both respective galectins. The present findings reflect the phylogenetic relationship between the two parasites and endorse the appropriateness of the cattle O. ochengi model for O. volvulus infection research.
Asunto(s)
Galectinas/administración & dosificación , Galectinas/genética , Inmunoglobulina G/sangre , Leucocitos Mononucleares/inmunología , Onchocerca/inmunología , Animales , Bovinos , Clonación Molecular/métodos , Femenino , Galectinas/inmunología , Perfilación de la Expresión Génica , Proteínas del Helminto/administración & dosificación , Proteínas del Helminto/genética , Proteínas del Helminto/inmunología , Humanos , Inmunización , Leucocitos Mononucleares/parasitología , Onchocerca/genética , Filogenia , Ratas , Ratas Wistar , Proteínas Recombinantes/administración & dosificación , Proteínas Recombinantes/inmunología , Análisis de Secuencia de ADNRESUMEN
Cycloviruses, small ssDNA viruses of the Circoviridae family, have been identified in the cerebrospinal fluid from symptomatic human patients. One of these species, cyclovirus-Vietnam (CyCV-VN), was shown to be restricted to central and southern Vietnam. Here we report the detection of CyCV-VN species in stool samples from pigs and humans from Africa, far beyond their supposed limited geographic distribution.
