Related Experiment Videos
Immunoglobulin G dimer: an idiotype-anti-idiotype complex.
D L Tankersley1, M S Preston, J S Finlayson
1Office of Biologics Research and Review, Division of Blood and Blood Products, Bethesda, MD 20892.
Molecular Immunology
|January 1, 1988
Summary
Pooled human immunoglobulin G (IgG) contains significant dimer levels, unlike monomeric IgG from single donors. Dimerization involves idiotype-anti-idiotype interactions, suggesting in vivo suppression mechanisms.
Area of Science:
- Immunology
- Protein Chemistry
- Biochemistry
Background:
- Immunoglobulin G (IgG) is a key antibody found in human plasma.
- Pooled human plasma IgG often contains a substantial percentage of IgG dimers, contrasting with monomeric IgG from individual donors.
Purpose of the Study:
- To investigate the formation and characteristics of IgG dimers.
- To identify the molecular mechanisms underlying IgG dimerization.
Main Methods:
- Analysis of IgG composition from pooled versus single-donor plasma.
- Experimentation with varying temperature and pH to observe dimer formation.
- Assessment of the role of antibody-combining sites (paratopes) and the Fc region in dimerization.
Main Results:
- IgG from pooled plasma showed up to 40% dimer content, while single-donor IgG was monomeric.
- Dimer levels correlated with the number of donors in the plasma pool.
- Dimerization was reversible by altering temperature or pH.
- Two intact antibody-combining sites were necessary for dimer formation, but the Fc region was not.
Conclusions:
- IgG dimers in pooled plasma likely represent idiotype-anti-idiotype pairs formed between IgG molecules from different individuals.
- Evidence suggests an in vivo mechanism actively suppresses idiotype-anti-idiotype formation.