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Shared surface epitopes among trypanosomes of the same serodeme expressing different variable surface glycoprotein
A F Barbet1, P J Myler, R O Williams
1Department of Veterinary Microbiology and Pathology, Washington State University, Pullman.
Molecular and Biochemical Parasitology
|January 15, 1989
Summary
African trypanosomes use antigenic variation via variable surface glycoproteins (VSGs) to evade immunity. This study reveals shared epitopes among different VSGs in Trypanosoma brucei clones, suggesting evolutionary links.
Area of Science:
- Parasitology
- Immunology
- Molecular Biology
Background:
- African trypanosomes evade host immunity through antigenic variation.
- This process involves changes in the variable surface glycoprotein (VSG).
- Previous studies indicated limited homology between VSGs of different trypanosome clones.
Purpose of the Study:
- To investigate epitope sharing among VSGs from different Trypanosoma brucei clones.
- To explore the homology and genetic basis of VSG expression in T. brucei.
Main Methods:
- Monoclonal antibody analysis to define exposed epitopes.
- Live cell immunofluorescence assays using rabbit antiserum.
- N-terminal amino acid sequencing and restriction mapping of VSG genes.
Main Results:
- Four T. brucei clones from the same serodeme expressed distinct VSGs but shared exposed epitopes to varying degrees.
- Antiserum against one VSG recognized epitopes on all four trypanosome clones.
- Expressed VSGs showed N-terminal homology with point substitutions, originating from a single gene family with unique expression-linked copies.
Conclusions:
- VSGs from the same serodeme can share epitopes, challenging previous assumptions.
- Partial N-terminal homology and shared epitopes suggest mechanisms for VSG repertoire evolution.
- Further analysis of VSG gene ontogeny is crucial for understanding trypanosome immune evasion strategies.