Could sharks be key to strengthening human immunity?

Over 400 million years of evolution, sharks' immune systems have evolved into finely tuned defenses, far more precise than those of humans and capable of resisting almost any dangerous virus or life-threatening tumor, the Daily Mail reports.  

This is thought to be one of the main reasons why some species, such as the great white shark, can live up to 70 years.

Now researchers at Elasmogen have solved the mystery of why sharks' immune systems are so effective at protecting them from disease. The findings could lead to new drugs to fight diseases such as cancer and rheumatoid arthritis.

In humans, when the immune system senses the presence of foreign cells (such as a virus or bacteria), it releases a protein called an antibody. It clings to a specific molecule on the surface of the virus or bacteria and triggers support from more powerful immune system cells, called T cells, to kill the invader.

Separately, scientists have developed artificial antibodies, "monoclonal" antibodies, which are injected into the body to target certain rogue cells, such as cancer cells. 

Once docked to their target, these synthetic antibodies turn on the immune system to attack the tumor cells (Herceptin, a drug used to treat some forms of breast and stomach cancer, is a monoclonal antibody).

But human and artificial antibodies are usually bulky Y-shaped molecules that, because of their size, are usually only able to bind to a small number of targets on invading cells. This helps explain why the human immune system and antibody-based drugs are not always 100% effective against the enemy.

Sharks have smaller antibodies than humans, allowing them to penetrate deeper into tiny cracks in the surface of bacteria or cancer cells, increasing the likelihood that they will "stick" and the immune system will destroy the invader.

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