The immune system is primed to recognise what is not self. A synthetic peptide can be recognised as foreign if its sequence differs from the body's own, if it includes unusual modifications or, very often, if it comes with aggregates or impurities, which are far more visible to immune cells than the isolated molecule.
When antibodies form against a peptide, they may have no consequences, they may neutralise its activity or speed up its clearance, and in rare cases they may cross-react with the body's own natural hormone. That is why anti-drug antibodies are measured systematically in peptide drug development.
In general, short peptides are poorly immunogenic, and the risk grows with size, with sequences foreign to the species and with the quality of the material.
Purity, absence of aggregates and handling technique are not only about “potency”: they also affect the immune response that can alter a study's results.
Related terms
Learn it in depth at the Peptide University
- Physical degradation: aggregation and adsorption · Module 11
- Antimicrobial peptides of innate immunity · Module 12
Definition for educational and scientific purposes. It is not medical advice or a recommendation for use. NeoPeptidos products are sold labelled for research use only (RUO).