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.
Publication types
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Research Support, U.S. Gov't, P.H.S.
MeSH terms
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Animals
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Binding Sites
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Cell Fusion*
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Fibroblasts / parasitology
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Glycoproteins / immunology
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Glycoproteins / metabolism
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Immunoglobulin Fab Fragments / immunology
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Ligands
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Macrophages / parasitology
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Mice
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Mice, Inbred BALB C
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Muscles / cytology
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Muscles / parasitology
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Neuraminidase / immunology
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Neuraminidase / metabolism
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Neutralization Tests
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Receptors, Cell Surface / metabolism
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Trypanosoma cruzi / immunology
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Trypanosoma cruzi / metabolism
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Trypanosoma cruzi / pathogenicity*
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Trypanosomiasis / metabolism*
Substances
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Glycoproteins
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Immunoglobulin Fab Fragments
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Ligands
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Receptors, Cell Surface
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trans-sialidase
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Neuraminidase