title: A novel cell surface trans-sialidase of Trypanosoma cruzi generates a stage-specific epitope required for invasion of mammalian cells.
abstract: When trypomastigotes of T. cruzi emerge from cells of the mammalian host, they contain little or no sialic acids on their surfaces. However, rapidly upon entering the circulation, they express a unique cell surface trans-sialidase activity. This enzyme specifically transfers alpha (2-3)-linked sialic acid from extrinsic host-derived macromolecules to parasite surface molecules, leading to the assembly of Ssp-3, a trypomastigote-specific epitope. The T. cruzi trans-sialidase does not utilize cytidine 5' monophospho-N-acetylneuraminic acid as a donor substrate, but readily transfers sialic acid from exogenously supplied alpha (2-3)-sialyllactose. Monoclonal antibodies that recognize sialic acid residues of Ssp-3 inhibit attachment of trypomastigotes to host cells, suggesting that the unusual trans-sialidase provides Ssp-3 with structural features required for target cell recognition.
authors.affiliation: Department of Pathology NYU Medical Center, New York 10016.
authors.forename: S
authors.initials: S
authors.lastname: Schenkman
authors.forename: M S
authors.initials: MS
authors.lastname: Jiang
authors.forename: G W
authors.initials: GW
authors.lastname: Hart
authors.forename: V
authors.initials: V
authors.lastname: Nussenzweig
mesh_terms: D000818:Animals; D000911:Antibodies, Monoclonal; D000913:Antibodies, Protozoan / Q000276:immunology; D000953:Antigens, Protozoan / Q000276:immunology*; D000939:Epitopes; D005455:Fluorescent Antibody Technique; D006001:Glycoconjugates / Q000378:metabolism; D006023:Glycoproteins; D019158:N-Acetylneuraminic Acid; D009439:Neuraminidase / Q000302:isolation & purification / Q000378:metabolism*; D015800:Protozoan Proteins / Q000276:immunology; D012794:Sialic Acids / Q000276:immunology; D012795:Sialoglycoproteins / Q000276:immunology*; D013379:Substrate Specificity; D014349:Trypanosoma cruzi / Q000201:enzymology* / Q000276:immunology*
chemical_list: D000911:Antibodies, Monoclonal; D000913:Antibodies, Protozoan; D000953:Antigens, Protozoan; D000939:Epitopes; D006001:Glycoconjugates; D006023:Glycoproteins; D015800:Protozoan Proteins; D012794:Sialic Acids; D012795:Sialoglycoproteins; C064783:sexual stage specific protein, Plasmodium; C069715:trans-sialidase; D009439:Neuraminidase; D019158:N-Acetylneuraminic Acid