Effect of shark cartilage derived protein on the NK cells activity

Abstract

Context: Shark cartilage has been used for its beneficial effects on various diseases. There are evidences, that shark cartilage stimulates cellular and humoral immune responses, which makes it an anti-tumor and immunomodulator candidate.Objective: The immunostimulatory effect of shark cartilage derived proteins on the cytotoxic activity of natural killer (NK) cells from healthy human peripheral blood mononuclear cells was studied.Material and methods: The shark cartilage was extracted and its bioactive proteins were purified using ion-exchange chromatography (DE-52) and sequential fractionation on Amicon ultrafiltration membranes. The effect of each protein fraction on the modulation of cytotoxic activity of NK cells, as effectors, against K562, as target cells, was assayed by enzymatic lactate dehydrogenase test.Results: The most immunostimulatory effect on the cytotoxic activity of NK cells was observed for AR10 fraction, containing proteins with molecular weight of about 14.5 kDa on the reducible discontinuous sodium dodecyl sulfate polyacrylamide gel electrophoresis.Discussion: Among the examined shark cartilage derived proteins, the most immunostimulatory effects on the NK cells cytotoxicity was found for AR10 fraction with molecular weight of about 14 kDa. We propose—the direct interactions of shark cartilage derived proteins with NK cells surface receptors may lead to the enhancing in the cytotoxic activity of NK cells.Conclusion: Thus AR10 fraction, proteins of about 14.5 kDa, has a novel immunostimulatory effect on the NK cells activity in vitro and if confirmed by in vivo trials, it may lead to its future clinical applications as, immunotherapy of cancer, HIV, and augmentation of host immune system related immunodeficiency disorders.