The immunomodulatory effects of shark cartilage on the mouse and human immune system

Background: Sharks get cancer rarely. A major difference between these animals and other species is that sharks have a great amount of cartilaginous tissue. Immunomodulatory effects of the cartilage of some species (cow) have been proved. Because the immune system has a major role in the defense of the body against cancer, we studied the effects of shark cartilage on the mouse and human immune system. Materials and methods: In an experimental study, the effects of different doses of shark cartilage on humoral (antibody titer) immune response against sheep red blood cells (SRBC), were measured in mouse. In addition, we evaluated the modulatory effects of the shark cartilage on the natural killer (NK) activity of the peritoneal cells of mouse against a tumor cell line called K562, according to the standard methods. The proliferative response of the human peripheral blood mononuclear cells was measured under the influence of shark cartilage. Results: Pure shark cartilage enhanced antibody response against SRBC in vivo. The hemagglutination titer which was 1/147 in the control group (injected with hen cartilage), increased to 1/1355 in the test group. The optimal dose was 100 mg/ml. both type of cartilage had blastogenic effect on peripheral blood mononuclear cells (the blastogenic index was 6.7 and 4.9 for impure shark cartilage and hen cartilage, respectively). NK activity was inhibited completely by pure shark cartilage (the amount of the killing activity of the effector peritoneal cells for the control and test groups against target cells was 25.9% and 5.5% respectively). Conclusion: Shark cartilage has a potent immunomodulatory effect on the specific immune mechanisms and some inhibitory effects on the innate immune mechanisms such as NC activity. Since the specific immunity has a more pivotal role against tumor formation, shark cartilage can be used as a cancer immunotherapeutic.