title: A ligand that Trypanosoma cruzi uses to bind to mammalian cells to initiate infection.
abstract: We purified a soluble gp83 trans-sialidase (gp83-TSA), from phospholipase C-treated Trypanosoma cruzi trypomastigote membranes, which binds to myoblasts, fibroblasts and macrophages to mediate trypanosome entry. Myoblasts display a single class of receptors for the gp83-TSA present at 4x10(4) per myoblast with a K(d) of 8 nM. Monovalent Fab fragments of the monoclonal antibody 4A4 specific for gp83-TSA inhibit gp83-TSA binding to myoblasts, fibroblasts and macrophages, block the trypanosomes from attaching to and entering these cells and neutralize T. cruzi infection in BALB/c mice. This is the first demonstration that gp83-TSA is a ligand that T. cruzi uses to attach to cells.
authors.affiliation: Department of Microbiology, School of Medicine, Meharry Medical College, 1005 Dr. D.B. Todd Jr. Blvd., Nashville, TN 37208, USA. fvillalta@mmc.edu
authors.forename: F
authors.initials: F
authors.lastname: Villalta
authors.forename: C M
authors.initials: CM
authors.lastname: Smith
authors.forename: A
authors.initials: A
authors.lastname: Ruiz-Ruano
authors.forename: M F
authors.initials: MF
authors.lastname: Lima
mesh_terms: D000818:Animals; D001665:Binding Sites; D002459:Cell Fusion; D005347:Fibroblasts / Q000469:parasitology; D006023:Glycoproteins / Q000276:immunology / Q000378:metabolism; D007140:Immunoglobulin Fab Fragments / Q000276:immunology; D008024:Ligands; D008264:Macrophages / Q000469:parasitology; D051379:Mice; D008807:Mice, Inbred BALB C; D009132:Muscles / Q000166:cytology / Q000469:parasitology; D009439:Neuraminidase / Q000276:immunology / Q000378:metabolism; D009500:Neutralization Tests; D011956:Receptors, Cell Surface / Q000378:metabolism; D014349:Trypanosoma cruzi / Q000276:immunology / Q000378:metabolism / Q000472:pathogenicity*; D014352:Trypanosomiasis / Q000378:metabolism*
chemical_list: D006023:Glycoproteins; D007140:Immunoglobulin Fab Fragments; D008024:Ligands; D011956:Receptors, Cell Surface; C069715:trans-sialidase; D009439:Neuraminidase