title: Trypanosoma cruzi: monoclonal antibodies to the surface glycoprotein superfamily differentiate subsets of the 85-kDa surface glycoproteins and confirm simultaneous expression of variant 85-kDa surface glycoproteins.
abstract: Most surface glycoproteins expressed by mammalian-stage forms of Trypanosoma cruzi are homologous to the parasite's trans-sialidase and therefore are members of the parasite's trans-sialidase superfamily. Few members of this superfamily have trans-sialidase activity. The SA85-1 family is a subfamily of the trans-sialidase superfamily whose members lack trans-sialidase activity. The function of these non-trans-sialidase members remains unknown. In this report a series of monoclonal and polyclonal antibodies to the SA85-1 glycoproteins is presented. The mAbs define distinct subgroups of SA85-1 glycoproteins, and these distinct subgroups are simultaneously expressed by individual trypomastigotes, supporting previous studies indicating that multiple SA85-1 glycoproteins and trans-sialidase superfamily glycoproteins are simultaneously expressed by each trypomastigote. In addition, the antibodies define two major subsets of the SA85-1 family (subset 1 and subset 2) based on differences in migration in SDS-PAGE; the subsets do not appear to be created by differences in glycosylation. Subset 1 migrates slower and is spontaneously released or shed preferentially from the parasite surface compared to subset 2. In addition, subset 1 is attached to the trypomastigote surface by a GPI linkage. Since these glycoprotein subsets are differentially expressed, they may have different functions.
mesh_terms: D000818:Animals; D000911:Antibodies, Monoclonal / Q000276:immunology*; D000918:Antibody Specificity; D000953:Antigens, Protozoan / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism; D015153:Blotting, Western; D004797:Enzyme-Linked Immunosorbent Assay; D005434:Flow Cytometry; D006023:Glycoproteins / Q000145:classification / Q000276:immunology* / Q000378:metabolism; D008562:Membrane Glycoproteins / Q000276:immunology / Q000378:metabolism; D015800:Protozoan Proteins / Q000276:immunology / Q000378:metabolism; D014349:Trypanosoma cruzi / Q000254:growth & development / Q000276:immunology*; D014643:Variant Surface Glycoproteins, Trypanosoma / Q000276:immunology* / Q000378:metabolism*