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The structure of a myelin basic protein-associated idiotope
C C Maier1, R D LeBoeuf, S R Zhou
1Center for Neuroimmunology, University of Alabama, Birmingham 35294-0005.
Journal of Neuroimmunology
|July 1, 1993
Summary
A cross-reactive idiotope (CRI) on antibodies targeting myelin basic protein (MBP) was structurally correlated with a synthetic peptide. This suggests the CRI is partly defined by a specific peptide sequence within the antibody light chain.
Area of Science:
- Immunology
- Structural Biology
- Biochemistry
Background:
- A cross-reactive idiotope (CRI) has been identified on monoclonal antibodies (mAbs) targeting encephalitogenic peptides of myelin basic protein (MBP).
- An anti-CRI mAb, F25F7, recognizes an idiotope (Id) on the light chains of anti-MBP peptide 1-9 mAb (F23C6) and anti-MBP peptide 80-89 mAb (845D3).
Purpose of the Study:
- To further delineate the structural basis of the CRI recognized by the F25F7 mAb.
- To investigate the relationship between the CRI and the synthetic peptide PBM 9-1 used to generate anti-idiotypic antibodies.
Main Methods:
- Sequence comparison between the light chain of mAb F23C6 and the synthetic peptide PBM 9-1.
- Structural analysis by comparing F23C6 light chain to the homologous mAb HyHEL-10.
- Inhibition assays using a synthetic peptide representing the F23C6 light chain CDR 2/FWK 3 sequence.
Main Results:
- A region of homology was found in CDR 2/FWK 3 between the F23C6 light chain and PBM 9-1.
- The structural configuration of this site in F23C6 light chain aligns with rules for defining antigenic determinants (Ids).
- A synthetic peptide mimicking the F23C6 VL CDR 2/FWK 3 sequence inhibited F25F7 binding to F23C6 and 845D3.
Conclusions:
- The idiotope recognized by F25F7 is structurally correlated with the synthetic peptide PBM 9-1.
- The data strongly suggest that the CRI is, in part, defined by a PBM 9-1-like sequence within the antibody light chain.