title: Antigenic variation and the surface glycoproteins of Trypanosoma congolense.
abstract: Two Trypanosoma congolense variant-specific glycoproteins, which are expressed sequentially during a relapsing infection, have been purified. The proteins, termed VSG-1 and VSG-2, both have a molecular weight of 53,000 as determined by SDS polyacrylamide electrophoresis. When either antigen is electrophoresed through a pH gradient on an isoelectric focusing (IEF) gel, it gives a characteristic spectrotype of three bands. The IEF components of each VSG are antigenically similar to each other but not identical. The components of VSG-1 are immunologically distinct from the components of VSG-2, as shown by lack of cross-reactivity. The three spectrotypes may reflect microheterogeneity in amino acid sequence among the components. Both VSG-1 and VSG-2 are selectively cleaved by trypsin near their carboxy-terminal ends, indicating the existence of a possible common VSG region. Significant homology in the aminoterminal amino acid sequences of VSG-1 and VSG-2 suggests that sequentially reduplicated genes are sequentially expressed by trypanosomes during relapsing infections.
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D000954:Antigens, Surface / Q000235:genetics / Q000276:immunology*; D000939:Epitopes / Q000235:genetics / Q000276:immunology; D005813:Genes, Synthetic; D006023:Glycoproteins / Q000235:genetics / Q000276:immunology*; D007525:Isoelectric Focusing; D051379:Mice; D008815:Mice, Inbred Strains; D009693:Nucleic Acid Hybridization; D051381:Rats; D014345:Trypanosoma / Q000235:genetics / Q000276:immunology*
chemical_list: D000954:Antigens, Surface; D000939:Epitopes; D006023:Glycoproteins