How Your Immune System Works


Your immune system plays an important role in protecting your body from illness-causing germs like bacteria, viruses, parasites and fungi, as well as harmful environmental substances. A healthy immune system can provide a powerful defense against these germs, so much so that you may never end up developing symptoms after exposure.

Get to know the parts of your immune system as well as what you can do to make your immune system work harder for you.

White Blood Cells

White blood cells are a major part of the immune system responsible for fighting germs and helping your body build immunity to them in the future. A phagocyte is a type of white blood cell that attacks and destroys invading organisms. A lymphocyte is a different type of white blood cell that records information about the invading organisms so that your body can remember how to properly fight them in the future.

B Cells and T Cells

Lymphocytes live in your bone marrow, eventually maturing into what are known as T cells and B cells. The job of B cells is similar to military intelligence—they are tasked with locating invading germs (called antigens) and launching an attack against them in the form of antibodies and T cells.

The antibodies created by the B lymphocytes find invading antigens and mark them for destruction. T cells then come in and eliminate the germs, much like a search-and-destroy mission. After the battle, your body holds onto the antibodies in case it has to fight the same germ again. That’s why there are some diseases out there that you usually won’t get sick from more than once (like chickenpox).

The Three Types of Immunity

Your immune system is smart—so smart, in fact, that it can provide protection in multiple ways. We call these forms of immunity passive, innate and adaptive.

Passive immunity is a temporary form of protection that is provided from the antibodies of another source, either naturally or artificially. One example is the temporary immunity provided by a mother’s breast milk.

Innate immunity is the basic protection we are naturally born with. From day one, our bodies have at least some ability to detect when a germ or substance might be harmful.

Finally, adaptive immunity is the long-lasting protection we develop over time by being exposed to environmental threats. As we collect antibodies against germs, our immune systems become more resilient to infection and disease.

Immune System Disorders

When the immune system becomes over- or under-active, immune disorders occur. Autoimmune diseases happen when the immune system overproduces antibodies, which start attacking the body’s own tissues. This can lead to diseases like lupus, rheumatoid arthritis, diabetes, Hashimoto’s and Graves’ disease.

On the flip side, immune deficiencies cause the immune system to under-produce antibodies, which leaves the body more vulnerable to infection.

Supporting a Healthy Immune System

When autoimmune diseases aren’t present, an unhealthy immune system can simply be the result of certain lifestyle decisions we may be unknowingly making. In this case, making a few changes can significantly improve our body’s ability to fight disease without medication.

When your immune system is functioning at its best, you may never feel a symptom of a virus that enters your body because your immune system is already hard at work fighting it off. People with thriving immune systems tend to get sick less often and may even experience shorter or more mild symptoms when they do get sick.

The top three areas in life that directly affect immune health are nutrition, stress and sleep. Eating well, managing stress and getting plenty of restful sleep are key habits for developing a healthy immune system.

If you’re in need of an immune system boost, consider doing MyHealthKC’s 21-Day Immunity Challenge. Developed in partnership with Tereza Hubkova, MD, ABIHM, ABIM, Integrative Medicine Specialist at AdventHealth Whole Health Institute, the challenge will walk you through important habits that can significantly improve your immune health in as little as three weeks.

For more information on the immune system, check out the following articles on MyHealthKC:

Out of Crisis with a Call for Whole Health
Adaptogens: Nature’s Gift for Times of Stress