Thermo Scientific Imject Mariculture KLH is a purified keyhole limpet hemocyanin carrier protein that enables simple preparation of highly effective immunogens with peptide antigens.
KLH is the most popular and immunogenic carrier protein used for preparation of peptide antigens for immunization and antibody production. KLH preparations in phosphate buffer are ready for hapten-carrier conjugation via amine-reactive NHS-ester or glutaraldehyde crosslinking. Preparations in MES buffer are optimized for peptide-carrier conjugation via the carboxyl-reactive carbodiimide crosslinker called EDC (or EDAC).
Carrier proteins are large, complex molecules capable of stimulating an immune response upon injection. Successful production of antibodies specific to small antigens (i.e., peptides or drug compounds) requires that these haptens be covalently conjugated to a larger, more complex molecule (usually a protein) to make them immunogenic. Carrier proteins are chosen based on immunogenicity, solubility, and whether adequate conjugation with the carrier can be achieved.
Keyhole limpet hemocyanin (KLH) is widely used as a carrier protein for conjugation to haptens and other antigens to make them more immunogenic for the purpose of antibody production. Because of its large mass and complexity, KLH elicits a stronger immune response than other carrier proteins. Because the protein is derived from a mollusk, it is phylogenetically distant from mammalian species and less likely to produce antibodies that will cross-react with typical target samples in assays.
Imject Mariculture KLH (mcKLH) is KLH that has been harvested from limpets grown in mariculture rather than captured from the wild. Imject mcKLH provides the highest possible immunogenicity; it is purified and lyophilized in buffers that optimize its stability and solubility for hapten conjugation. As a large protein, KLH has hundreds of primary amines and carboxyl groups that can be targeted for conjugation with NHS-ester, EDC, and other crosslinking reagents.
The carbodiimide crosslinker EDC conjugates carboxyl-containing haptens to the highly immunogenic KLH carrier protein for immunization and antibody production. This method of immunogen preparation is ideal for peptide antigens with few or no aspartic and glutamic acid residues (carboxylates) and lysine residues (primary amines) within the central portion of the primary sequence. Because peptides contain both carboxylate and amines, EDC conjugation results in their becoming variously polymerized and randomly oriented in their linkage to the carrier protein. Typically, this results in a high level of antigen loading on the carrier protein as well as presentation in all possible orientations for antibody production.
