For most, thoughts about the immune system only occur with the occasional cut, cold or flu, when healing directly depends on the immune system doing its job. And when you’re healthy, the immune system goes unnoticed, acting as the body’s security and defense system.
A complex system of cells, tissues and organs, the immune system’s sole purpose is to recognize and keep out foreign invaders to prevent infections and diseases in the body.
“Think of the body like the leftovers in your refrigerator, they’re going to get moldy. Our bodies don’t get moldy because our immune system recognizes many different invaders and cleans them out,” explains Diane Hollenbaugh, Ph.D., senior director, oncology discovery, AbbVie. “It is a complex task because of the different invaders and the different assaults on your body, which means your immune system has to recognize all these attacks, react and remove the threat.”
From friend to foe
However, the immune system can go haywire, betraying itself.
“In rheumatoid arthritis, for example, the immune system is over-activated and attacks the body’s own tissue,” says Gillian Kingsbury, senior principal research scientist, immunology early discovery, AbbVie. “This attack causes inflammation in the joints that creates pain and destruction of the joint tissue.”
In cancer, and under normal circumstances, the immune system recognizes cancerous or mutated cells in the body and responds appropriately. However, as the cancerous cells mutate and grow, they find ways to trick the immune system into ignoring them and eventually hide from the immune system altogether.
Fiona Harding, Ph.D., research fellow, discovery oncology, AbbVie, explains, “Cancerous cells and tumors can and do stay visible to the immune system, but bring along protective gear and find ways to subvert it allowing cancer to grow in the body.”