Peptide Conjugated KLH, BSA or OVA

Short peptides are usually too small to elicit a sufficient immune response. Therefore, it is necessary to conjugate the peptide to a larger carrier protein to promote a robust immune response and generate high levels of specific antibodies. Biorunstar provides the following most commonly used carrier proteins for peptide conjugates:

KLH (keyhole limpet hemocyanin, MW 4.5 × 10⁵ - 1.3 × 10⁷ Da) is a copper-containing protein isolated from Megathura crenulata and is generally the first-choice carrier protein due to its high immunogenicity. Peptides conjugated to KLH often have limited solubility in water due to the protein's size and structure; however, this does not affect its immunogenicity, and cloudy solutions can still be used for immunizations.

BSA (bovine serum albumin, MW 67 × 10³ Da) is a popular carrier protein for weakly antigenic compounds due to its accessible lysine residues. Being smaller, BSA is more water-soluble than KLH and is commonly used in immunoassays. However, since BSA is often used to block nonspecific binding, BSA conjugates should not be used for immunization if the assay system uses BSA, as this may lead to false positives due to antibodies against BSA in the antisera.

OVA (ovalbumin, MW 45 × 10³ Da) is a protein isolated from chicken eggs. It is commonly used as a control carrier protein to verify that antibodies are specific to the target peptide rather than to the carrier protein (e.g., KLH/BSA).

Generally, the choice of conjugation chemistry depends on the provided antigen peptide sequence.