General introduction to hemocyanins

Hemocyanins are respiratory proteins that use copper binding sites to bind and transport oxygen in a variety of arthropods and mollusks. Hemocyanins, like hemoglobin, are multi-subunit molecules where each subunit (arthropods) or functional unit of a subunit (mollusks) binds oxygen.

Typically, hemocyanins have a high molecular weight; and pH, temperature and ionic concentration modulate the oxygen affinity. The subunit of hemocyanin has a tendency to aggregate.

Keyhole Limpet Hemocyanin
Prof. Dr. Jürgen Markl, Direktor Zoologisches Institut der Johannes Gutenberg-Universität Mainz, Germany

Hemocyanin is isolated from the hemolymph of the animals. The copper in the protein is in the form of Cu(I) and is bound directly to the amino acid side chain, as opposed to the metal being bound to a prosthetic group, as in hemoglobin.

The oxygenated molecule generates the characteristic light absorbance in the near ultraviolet region, around 343 nm, responsible for the blue color of hemocyanins. The hemocyanins from mollusks and arthropods are quite different in weight, subunit structure and oxygen binding capacity.

Keyhole Limpet Hemocyanin Structure
Prof. Dr. Jürgen Markl, Direktor Zoologisches Institut der Johannes Gutenberg-Universität Mainz, Germany

Hemocyanins are strong immunogens

Because of its high molecular weight, structural heterogeneity and completely xenogeneic nature - mollusks and arthropods have been separated from vertebrates as protostomia for at least 600 million years - hemocyanin is one of the strongest antigens known. 

In mammalians it leads to the formation of very powerful antiserum, moves the T4/T8 ratio in favor of the T4 helper cells and at the site of application leads to local erythema and invasion by macrophages.

Hemocyanin has been in use as an immunological re-agent for many years. It is used as a carrier protein for antibody production against antigens.

As such, some chemical companies have been marketing the crude and partially refined grade of hemocyanins, specifically the hemocyanin from a mollusk, the Giant Keyhole Limpet, Megathura crenulata (commonly abbreviated as KLH), for over 30 years.

Hemocyanins as carrier proteins

Recent advances in immunology and the role immune system plays in diseases have opened a whole new era of product development activities aimed at developing novel therapeutics which is aimed at teaching the body's immune system to fight diseases like cancer, AIDS, etc.

The approach involves the use of highly immunogenic molecule, like the hemocyanin for non-specific immunostimulation (NSI), or active specific immunostimulation (ASI), using conjugate vaccines, wherein the tumor (disease) specific antigens are covalently bound to carrier protein like KLH and the product used in human clinical studies. Such products are termed 'vaccines'.

The need for such vaccine development is associated with the production and manufacture of large quantities of safe human products. The hemocyanin in such vaccines is an active component and should meet the stringent regulatory requirements, i.e., it must be a safe, characterized product of high quality with batch-to-batch consistency.

biosyn hemocyanin business initiated 1985

The biosyn hemocyanin business plan was initiated in 1985, and included the regulatory and quality aspect built into the development program.

As a result of the well-charted development course, biosyn is now the world leader in the manufacture and supply of high-quality clinical and research-grade hemocyanin products.

biosyn hemocyanin products include a variety of different and novel formulations derived from the mollusks, giant keyhole limpet and abalone and the arthropod horseshoe crab.