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Variant specific epitopes of Giardia lamblia
T E Nash1, J T Conrad, J W Merritt
1Laboratory of Parasitic Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892.
Molecular and Biochemical Parasitology
|August 11, 1990
Summary
Giardia lamblia exhibits antigenic variation, with most isolates lacking genes for surface epitopes. This study investigated epitope expression in different Giardia isolates using monoclonal antibodies.
Area of Science:
- Parasitology
- Immunology
- Molecular Biology
Background:
- Giardia lamblia, a protozoan parasite, is known to undergo surface antigenic variation.
- This variation is crucial for immune evasion during infection.
Purpose of the Study:
- To determine the capability of different Giardia lamblia isolates and clones to express specific surface epitopes.
- To investigate the genetic basis for the lack of epitope expression in certain isolates.
Main Methods:
- Utilized four surface-reacting monoclonal antibodies (mAbs) against Giardia variants.
- Employed direct and indirect immunofluorescence assays to assess epitope reactivity.
- Conducted Southern blot analysis to investigate gene presence.
Main Results:
- Eleven of 28 Giardia isolates expressed epitopes recognized by mAbs 6E7, 5C1, and 3F6.
- Lack of gene expression was identified as the reason for non-reactivity in most isolates.
- Analysis of mAb 6E7 reactive clones revealed variations in the molecular masses of recognized surface antigens.
Conclusions:
- Giardia lamblia isolates exhibit diverse capabilities in expressing surface antigenic epitopes.
- The absence of specific genes is a primary factor limiting epitope expression in many isolates.
- Further research is needed to understand the molecular basis of antigenic variation in Giardia.