KLH is expressed in two isoforms (KLH1 and KLH2) assembled into decamers and didecamers of 4 MDa to 8 MDa molecular weight. The subunit isoforms (approximately 400-600 kDa monomeric molecular weight) are each composed of 7 or 8 functional unit; each unit having an oxygen binding site of two copper atoms.

Both the high molecular weight native molecule and subunit KLH are excellent immune stimulants.

KLH is an effective and safe carrier molecule in active immunotherapies being developed for the treatment of cancer, inflammatory diseases, immune disorders and Alzheimer’s disease, among other diseases.

As a carrier molecule, KLH is combined, or conjugated, to vaccine antigens that are used to promote the generation of antibody and cell-mediated immune responses against targeted diseases. By themselves, the small haptens (partial antigens) and vaccine antigens used to target these diseases are not usually immunogenic enough to awaken the immune system and therefore, require a carrier molecule or adjuvant, like KLH, in order to be effective. KLH is ideal in this role due to its immune-stimulating properties, large size, numerous sites for antigen conjugation, and safety profile.

KLH has diagnostic applications as a finished injectable product. It is extensively used by pharmaceutical companies and researchers as a safe, immune-stimulating antigen in drug immunotoxicology and assessment of immune status.

KLH is a standard immunogen in T-Cell Dependent Antibody Response (TDAR), a functional assay used to assess an antibody response. TDAR with KLH is widely recognized as a test for monitoring the effects of drugs on the immune system.