The Immune System

Important to Know: 

  • Your immune system is a complex, coordinated “army” that works together to recognize and destroy foreign and abnormal cells in your body
  • White blood cells called T cells and B Cells play a key role in attacking and killing abnormal cells

Your immune system is like an army. It has many different kinds of “soldiers,” all with different functions that work together to protect your body from invaders such as bacteria, viruses or abnormal or unhealthy cells that cause disease. 

Some of these soldiers recognize the unhealthy cells, others communicate with other cells or tissues in your body, while others are the fighters that attack and destroy the enemy. 

Dr. Schuchter: Role Of The Immune System

The immune system includes a network of cells, tissues and organs including: 

  • Blood Cells: There are many kinds of blood cells, but the most common immune blood cells are white cells, or lymphocytes, called T cells and B cells. These and other blood cells play an important role in the immune system.
  • The Lymphatic System: Is a network of channels and tissues that go throughout the body, and includes the “lymph nodes,” the thymus gland and the spleen. The lymph system is critical to moving immune cells to the various tissues and removing “debris” from the system.
  • Organs: Many organs, including the skin, thymus gland and spleen, play an important role in the immune system.


T cells
are white blood cells that play a key role in the immune system and immunotherapy for cancer. They are the core of “adaptive immunity,” the system that allows our bodies to recognize and attack foreign or unhealthy cells. Most cancer immunotherapy focuses on activating T cells to fight cancer.

B cells are white blood cells that produce antibodies that attack specific invaders or unhealthy cells. They are an important part of our immune system.

Knowing Self and Non-Self

The most important function of the immune system is to know the difference between self and non-self. Self means your own body tissues. Non-self means any abnormal cell or foreign invader, such as bacteria, viruses, parasites and fungus. Normally, your immune system will not attack anything that it identifies as a healthy part of self. 

The problem with cancer cells is that they arise from our cells, but there are differences. As they grow and spread, cancer cells undergo a series of changes, or mutations, becoming increasingly less like normal cells. 

Sometimes our immune system can detect these differences and respond. Other times, the cancer cells slip through the defenses or are actually able to inhibit the immune system.

Updated August 12, 2014