Understand How Your Immune System Works

Make sense of your body’s defenses against disease. Understanding how your immune system works could help you boost your immunity.


| August/September 2014



Two Girls Laughing

Laughter really is medicine! Studies show that positivity plays a part in improving immunity.


Photo by Dreamstime/Gillian08

We navigate a germy world. We handle money, borrow pens, share electronics, exchange kisses, shake hands, dig in gardens, clean litter boxes and change diapers. During our everyday business, we mingle with billions of microorganisms.

That we rarely succumb to infectious illness is downright miraculous, and our immune systems deserve most of the credit for that. The main function of this diffuse, interacting network of cells and chemicals is to combat pathogenic (disease-causing) microbes. It patrols the body for anything abnormal and potentially dangerous, such as cancer cells.

This complex and fascinating system affects your every waking hour, so learning how your immune system works will help you understand your body’s response to infection and shed light on how to boost your immunity. Let’s take a look inside. (See our Immune System chart for more details.)

Divide and Conquer

The immune system has two main divisions: the innate immune system, which needs no previous experience with intruders to dispatch them swiftly, and the acquired immune system, which requires contact and time in order to develop a specific response to a particular pathogen.

Innate. As its name suggests, the innate immune system is in place at birth. It reacts quickly and in a generalized fashion to any foreign invader. Physical barriers and reactions form a key component of this system: Skin and mucous membranes act like castle walls to keep out invaders. Eyelashes and nostril hairs trap dirt, microbes and pollen. Stomach acidity kills many microbes. Earwax keeps the inner ears healthy. Urination flushes out bacteria. Vomiting and diarrhea propel bad microbes from the intestinal tract. The gag, swallow and cough reflexes protect the body’s airways.

Fever is a second line of defense; it contributes by activating infection-fighting immune cells (“cytotoxic T cells”). White blood cells (called “leukocytes”) form another component of innate immunity. These include natural killer cells (which attack virus-infected cells and cancer cells); cells involved in allergic reactions; and several types of cells (“phagocytic cells”) capable of ingesting abnormal cells and bacteria, and other foreign material.

Some cells release “cytokines” — a large group of chemicals that facilitate communication among cells. Cytokines stimulate or inhibit activity of white blood cells, interfere with viral replication, and communicate with the brain. The brain, in turn, sends signals that influence the immune system and other bodily systems.





dairy goat

MOTHER EARTH NEWS FAIR

Aug. 5-6, 2017
Albany, Ore.

Discover a dazzling array of workshops and lectures designed to get you further down the path to independence and self-reliance.

LEARN MORE