title: Insights into the biological features of the antigenic determinants recognized by four monoclonal antibodies in redia and adult stages of the liver fluke Fasciola hepatica.
abstract: Fasciola hepatica is a digenean trematode which infects a wide variety of domestic animals and also humans. Previous studies have demonstrated that four monoclonal antibodies (Mabs) against the total extract of F. hepatica redia (named as 1E4, 6G11, 4E5 and 4G11) also recognized the excretion - secretion antigens (ES Ag) of adult parasites, which is a biologically-relevant mixture of molecules with functional roles during infection and immune evasion on definitive hosts. In the present report we describe the partial characterization of the epitopes recognized by these Mabs by heat treatment, mercaptoethanol reduction, pronase proteolysis and sodium peryodate oxidation, which suggested their predominant protein and conformational nature. Also, a comparative study using immunodetection assays on crude extracts and on histological sections of both rediae and adults of F. hepatica were performed to explore the expression pattern of the antigenic determinants in these developmental stages. From these experiments it was found that the Mabs reacted most likely with the same proteins of approximately 64 and 105 kDa present on both rediae and adult's extracts. However, the 1E4, 6G11 and 4E5 Mabs also recognized other molecules of the total extract of F. hepatica adults, a fact that constitutes an evidence of the antigenic variation between both stages and points at a certain biological relevance of the recognized antigenic determinants. Immunolocalization studies on histological sections revealed that all Mabs reacted with the tegument of F. hepatica in both rediae and adults stages, while the epitopes recognized by 1E4, 6G11 and 4E5 antibodies were also preferentially localized in the intestinal caeca and in different organs of the reproductive system of adult specimens. The immunogenicity of these antigenic determinants, their conserved status among different stages of the life cycle of F. hepatica and their presence in both tegument and ES Ag of adult parasites, are suitable features that suggest their potential use for developing an epitope-based vaccine for fasciolosis control.
authors.affiliation: Vicedirección de Investigaciones en Parasitología, Instituto de Medicina Tropical "Pedro Kourí", La Habana, Cuba. Electronic address: annia@ipk.sld.cu.
authors.forename: Annia
authors.initials: A
authors.lastname: Alba
authors.affiliation: Vicedirección de Investigaciones en Parasitología, Instituto de Medicina Tropical "Pedro Kourí", La Habana, Cuba.
authors.forename: Jorge
authors.initials: J
authors.lastname: Sánchez
authors.affiliation: Vicedirección de Investigaciones en Parasitología, Instituto de Medicina Tropical "Pedro Kourí", La Habana, Cuba.
authors.forename: Hilda
authors.initials: H
authors.lastname: Hernández
authors.affiliation: Departamento de Anatomía Patológica, Centro de Investigaciones Clínico Quirúrgicas, La Habana, Cuba.
authors.forename: Maryani
authors.initials: M
authors.lastname: Mosqueda
authors.affiliation: Departamento de Anatomía Patológica, Centro de Investigaciones Clínico Quirúrgicas, La Habana, Cuba.
authors.forename: Suanel Y
authors.initials: SY
authors.lastname: Rodríguez
authors.affiliation: Departamento de Anatomía Patológica, Instituto de Medicina Tropical "Pedro Kourí", La Habana, Cuba.
authors.forename: Virginia
authors.initials: V
authors.lastname: Capó
authors.affiliation: Laboratorio de Anticuerpos Monoclonales, Vicepresidencia de Investigaciones, Instituto Finlay, La Habana, Cuba.
authors.forename: Oscar
authors.initials: O
authors.lastname: Otero
authors.affiliation: Departamento de Anatomía Patológica, Centro de Investigaciones Clínico Quirúrgicas, La Habana, Cuba.
authors.forename: Carlos
authors.initials: C
authors.lastname: Alfonso
authors.affiliation: Vicedirección de Investigaciones en Parasitología, Instituto de Medicina Tropical "Pedro Kourí", La Habana, Cuba.
authors.forename: Ricardo
authors.initials: R
authors.lastname: Marcet
authors.affiliation: Vicedirección de Investigaciones en Parasitología, Instituto de Medicina Tropical "Pedro Kourí", La Habana, Cuba.
authors.forename: Jorge
authors.initials: J
authors.lastname: Sarracent
mesh_terms: D000818:Animals; D000911:Antibodies, Monoclonal / Q000276:immunology*; D000940:Antigenic Variation / Q000502:physiology; D000939:Epitopes / Q000737:chemistry / Q000276:immunology* / Q000378:metabolism; D005210:Fasciola hepatica / Q000187:drug effects / Q000276:immunology*; D007150:Immunohistochemistry; D008623:Mercaptoethanol / Q000494:pharmacology; D051379:Mice; D010084:Oxidation-Reduction; D010504:Periodic Acid / Q000494:pharmacology; D011402:Pronase / Q000378:metabolism; D013696:Temperature
chemical_list: D000911:Antibodies, Monoclonal; D000939:Epitopes; D010504:Periodic Acid; D008623:Mercaptoethanol; C009288:metaperiodate; D011402:Pronase
keywords: Antigenic variation; Epitope characterization; Fasciola hepatica; Monoclonal antibody; Rediae