Mapping of segmental antigenic determinants on structurally related variant surface glycoproteins of Trypanosoma brucei.
To study common and variant specific antigenic determinants on variant surface glycoproteins from Trypanosoma brucei, we have selected four serologically cross-reacting variant populations. Monoclonal antibodies were raised against the purified variant surface glycoproteins from each variant trypanosome population. Six monoclonal antibodies bind to segmental epitopes and one binds to a topographically assembled epitope. Amino acid compositions of these variant surface glycoproteins reveal striking conservation of certain residues including cysteine and charged amino acids. We also find that all seven monoclonal antibodies used in this study bind to protein determinants not exposed on the surface of the living trypanosome. Only one monoclonal antibody exhibits homologous specificity, while the remainder display cross-reactivity for three or all four variant surface glycoproteins. In addition, polyacrylamide gel electrophoresis peptide mapping and Western blots probed with each monoclonal antibody reveal significant peptide homologies. Furthermore, two pairs of monoclonal antibodies recognize two epitopes that are possibly immunodominant. The significance of these findings is discussed in terms of the structural similarities and differences among variant surface glycoproteins.
Carruthers
V B
VB
Department of Microbiology and Immunology, University of Western Ontario, London, Canada.
Clarke
M W
MW
D000596:Amino Acids / Q000032:analysis; D000818:Animals; D000911:Antibodies, Monoclonal; D000918:Antibody Specificity; D000940:Antigenic Variation; D000953:Antigens, Protozoan / Q000276:immunology*; D015153:Blotting, Western; D003429:Cross Reactions; D004591:Electrophoresis, Polyacrylamide Gel; D000939:Epitopes / Q000276:immunology*; D005455:Fluorescent Antibody Technique; D008562:Membrane Glycoproteins / Q000276:immunology*; D010449:Peptide Mapping; D014346:Trypanosoma brucei brucei / Q000276:immunology*
D000596:Amino Acids; D000911:Antibodies, Monoclonal; D000953:Antigens, Protozoan; D000939:Epitopes; D008562:Membrane Glycoproteins