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In Brief about Keyhole limpet hemocyanin (KLH)

April 19, 2017


KLH or Keyhole limpet hemocyanin is found in the hemolymph of the giant Keyhole limpet hemocyanin (KLH)keyhole limpet (marine mollusk), Megathura crenulata in the molecular study of KLH. It is an oxygen-carrying macro metalloprotein which found in the coastal areas of California. The transmission electron microscope (TEM) is greatly helped in the. The protein contains 2 genes KLH1 and KLH2 which are around 60% identical to each other. Oxygen combines with hemocyanin molecule to produce the characteristic transparent blue color due to copper ions. The protein loses its blue color if it is denatured or the copper ions are lost. The protein is immunogenic but is harmless and hence used as a vaccine carrier protein. Purification of KLH is done by ammonium sulphate precipitation, dialysis followed by chromatography.

As mentioned before the protein is extensively used as a carrier protein biotechnology research, medical therapeutics etc. It is being tested for development of cancer vaccines including melanoma, breast cancer, bladder cancer, non-Hodgkin’s Lymphoma etc. The vaccines contain tumor specific antigens bound to KLH which activates anti tumor immune response and destroys tumor cells. It is being used for the diagnosis of Schistosomiasis, treatment of drug addiction. Other areas of KLH research include study of inflammatory conditions, drug assay, Immune competence testing, assessment of stress etc. 

Ecological considerations

Because of the importance of Keyhole limpet hemocyanin (KLH) in research and technology, the Giant Keyhole Limpet is becoming of great concern to marine biologists and fisheries department in California. Overharvest of the species for commercial purposes is an issue. The species is not of abundant variety and some researchers have raised concerns over their threat to existence. To secure the source of KLH, Federal agencies including the National Science Foundation and National Institutes of Health are sponsoring research on marine research, culture and preservation of the Giant Keyhole Limpet.

Disclaimer: The information given in this write-up is purely for educating the reader. It is not meant to be a substitute for any advice from a medical expert.