title: Isolation and partial characterization of an immunogenic antigen of Giardia lamblia.
abstract: Humoral and cellular immune responses play an important role during Giardia lamblia infection. Several Giardia proteins have been identified as immunogenic antigens based on their elicited humoral immune response. Poorly is known about Giardia antigens that stimulate a cellular immune response. The main purpose of this study was to isolate and partial characterize an immunogenic antigen (5G8) of G. lamblia. The 5G8 protein was isolated from G. lamblia trophozoite lysates by affinity chromatography using moAb 5G8-coupled CNBr-Sepharose. The isolated protein was analysed by electrospray tandem mass spectrometry (ESI-MS/MS), and by diverse bioinformatics tools (GiardiaDB, BLASTn, BLASTp and ExPASy). Additionally, several biochemical and immunological characteristics of the isolated protein were analysed. By ESI-MS/MS the amino acidic 5G8 sequence was deduced. The 5G8 antigen belongs to the VSP family proteins of G. lamblia. This protein is composed by one polypeptide chain (±71kDa). Using the algorithm SYFPHEITI, we identified candidate CD4+T-cell epitopes from the 5G8 antigen, which can elicit cell-mediated immune responses. In this study, we have identified a G. lamblia protein that induces a strong immune response in infected mice. The biochemical and immunological characterization of the immunogenic 5G8 antigen may contribute to the rational design of a Giardia vaccine.
authors.affiliation: Health Science Department, University of Sonora, Blvd Bordo Nuevo s/n, Ejido Providencia, 85199 Cd Obregon, Sonora, Mexico.
authors.forename: Jael
authors.initials: J
authors.lastname: Quintero
authors.affiliation: Department of Chemistry-Biology, University of Sonora, Blvd. Luis Encinas and Rosales s/n, 83000, Hermosillo, Sonora, Mexico.
authors.forename: Alejandra
authors.initials: A
authors.lastname: Valdez
authors.affiliation: Department of Chemistry-Biology, University of Sonora, Blvd. Luis Encinas and Rosales s/n, 83000, Hermosillo, Sonora, Mexico.
authors.forename: Brenda
authors.initials: B
authors.lastname: Samaniego
authors.affiliation: Department of Nutrition and Metabolism, Centro de Investigación en Alimentación y Desarrollo AC, 83304 Hermosillo, Sonora, Mexico.
authors.forename: Gloria
authors.initials: G
authors.lastname: Lopez-Romero
authors.affiliation: Department of Nutrition and Metabolism, Centro de Investigación en Alimentación y Desarrollo AC, 83304 Hermosillo, Sonora, Mexico.
authors.forename: Humberto
authors.initials: H
authors.lastname: Astiazaran-Garcia
authors.affiliation: Department of Chemistry-Biology, University of Sonora, Blvd. Luis Encinas and Rosales s/n, 83000, Hermosillo, Sonora, Mexico.
authors.forename: Lucila
authors.initials: L
authors.lastname: Rascon
authors.affiliation: Department of Chemistry and Biochemistry, University of Arizona, 85721 Tucson, AZ, USA.
authors.forename: Linda
authors.initials: L
authors.lastname: Breci
authors.affiliation: Department of Chemistry-Biology, University of Sonora, Blvd. Luis Encinas and Rosales s/n, 83000, Hermosillo, Sonora, Mexico.
authors.forename: Adriana
authors.initials: A
authors.lastname: Garibay-Escobar
authors.affiliation: Department of Chemistry-Biology, University of Sonora, Blvd. Luis Encinas and Rosales s/n, 83000, Hermosillo, Sonora, Mexico.
authors.forename: Ramón
authors.initials: R
authors.lastname: Robles-Zepeda
authors.affiliation: Department of Chemistry-Biology, University of Sonora, Blvd. Luis Encinas and Rosales s/n, 83000, Hermosillo, Sonora, Mexico. Electronic address: velaz@guayacan.uson.mx.
authors.forename: Carlos
authors.initials: C
authors.lastname: Velazquez
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D000953:Antigens, Protozoan / Q000008:administration & dosage / Q000737:chemistry* / Q000235:genetics / Q000276:immunology* / Q000302:isolation & purification; D018985:Epitopes, B-Lymphocyte / Q000737:chemistry / Q000276:immunology / Q000302:isolation & purification; D018984:Epitopes, T-Lymphocyte / Q000737:chemistry / Q000276:immunology / Q000302:isolation & purification; D016829:Giardia lamblia / Q000276:immunology*; D007111:Immunity, Cellular; D056724:Immunity, Humoral; D008565:Membrane Proteins / Q000235:genetics; D051379:Mice; D015800:Protozoan Proteins / Q000008:administration & dosage / Q000235:genetics / Q000276:immunology / Q000302:isolation & purification / Q000378:metabolism; D053719:Tandem Mass Spectrometry; D053058:Trophozoites / Q000276:immunology
chemical_list: D000953:Antigens, Protozoan; D018985:Epitopes, B-Lymphocyte; D018984:Epitopes, T-Lymphocyte; D008565:Membrane Proteins; D015800:Protozoan Proteins; C103927:Vsp protein, Giardia intestinalis
keywords: Cellular response; Giardia lamblia; Humoral response; Immunogenic protein