title: Characterization of an immunodominant Giardia lamblia protein antigen related to alpha giardin.
abstract: The trophozoites of Giardia lamblia possess several protein antigens, predominant among them a protein of approximately 32,000 Da. In the present study, we used monospecific antibodies that recognize this protein to demonstrate its presence on a variety of G. lamblia isolates from human and animal sources. Immune electron microscopy was used to localize 32-kDa antigen on the trophozoite membrane and disk. Immunofluorescent assays employing monospecific antibodies confirmed the presence of 32-kDa antigen on the membrane and disk and its absence on flagella or nuclei. The N-terminal 17 amino acids of the 32-kDa antigen are identical to alpha-1-giardin, a protein component of microribbons on the ventral disk. These results suggest that the 32-kDa immunodominant trophozoite antigen is alpha-1-giardin.
authors.affiliation: Department of Pediatrics, University of Alberta, Edmonton, Canada.
authors.forename: W M
authors.initials: WM
authors.lastname: Wenman
authors.forename: R U
authors.initials: RU
authors.lastname: Meuser
authors.forename: Q
authors.initials: Q
authors.lastname: Nyugen
authors.forename: R T
authors.initials: RT
authors.lastname: Kilani
authors.forename: K
authors.initials: K
authors.lastname: el-Shewy
authors.forename: R
authors.initials: R
authors.lastname: Sherburne
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D000913:Antibodies, Protozoan; D000918:Antibody Specificity; D000953:Antigens, Protozoan / Q000235:genetics / Q000276:immunology / Q000302:isolation & purification*; D002465:Cell Movement; D003598:Cytoskeletal Proteins / Q000235:genetics / Q000276:immunology / Q000302:isolation & purification*; D005455:Fluorescent Antibody Technique; D016829:Giardia lamblia / Q000276:immunology* / Q000648:ultrastructure; D006031:Glycosylation; D016056:Immunodominant Epitopes / Q000235:genetics / Q000276:immunology / Q000302:isolation & purification*; D016253:Microscopy, Immunoelectron; D008969:Molecular Sequence Data; D011499:Protein Processing, Post-Translational / Q000187:drug effects; D015800:Protozoan Proteins / Q000235:genetics / Q000276:immunology / Q000302:isolation & purification*; D017421:Sequence Analysis; D014415:Tunicamycin / Q000494:pharmacology
chemical_list: D000913:Antibodies, Protozoan; D000953:Antigens, Protozoan; D003598:Cytoskeletal Proteins; D016056:Immunodominant Epitopes; D015800:Protozoan Proteins; C038207:giardin protein, Giardia lamblia; D014415:Tunicamycin