Peptide-protein conjugates are used to raise antibodies against specific peptide targets. Typically, though, the peptides alone are too small to elicit a sufficient immune response and are therefore covalently conjugated to a larger, more complex molecule (usually a protein) to make them immunogenic. Carrier proteins such as keyhole limpet hemocyanin (KLH), bovine serum albumin (BSA) and ovalbumin (OVA) contain tens to hundreds of epitopes that stimulate T-helper cells, which help induce the B-cell response that results in the biosynthesis of target-specific antibodies. Because the immune system reacts to the peptide-protein conjugate as a whole, antibodies are generated against epitopes on the carrier peptide, the linker and the carrier protein.
Carrier proteins are chosen based on immunogenicity, solubility and whether adequate conjugation with the carrier can be achieved. Because KLH is derived from a mollusk (Megathura crenulata; keyhole limpet), it is phylogenetically distant from mammalian species such as chickens and cows (the sources of OVA and BSA, respectively) and is less likely to produce antibodies that will cross-react with typical target samples in experimental assays.
Traditionally, KLH was obtained from giant keyhole limpets harvested directly from the natural environment. This method disturbs the sensitive shoreline ecosystems where these limpets live. Current methods to obtain KLH are much less threatening to the natural habitat and limpet species survival. Giant keyhole limpets are raised in tanks and harvested (marine culture or "mariculture") where they are occasionally milked of some of their fluids, similar to humans donating blood.
Hermanson, G.T. (2008). Bioconjugate Techniques. 2nd edition, Academic Press, New York. (Part 20036). Chapter 19 discusses carrier protein uses and immunogen preparation.
Peptide Analysis Tool
Antigen Profiler for Robust Peptide Antibody Design
Review of immunogen preparation, including more details about carrier proteins
Related Peptide Products:
OVA- and BSA-Peptide Conjugation Service
Custom Peptide Synthesis Service
Related Protein Conjugation Products:
Imject KLH Carrier Protein Conjugation Kits
Blue Carrier Protein Conjugation Kits
BSA Carrier Protein Conjugation Kits
Catonized BSA Carrier Protein Conjugation Kits
Ovalbumin (OVA) Carrier Protein Conjugation Kits
Learn about all Peptide Products