All About the Immune System

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We live our lives with the ever-present risk of coming into contact with health-harming agents that cause sickness. Fortunately, we are protected by our immune system. This powerful protector of wellness acts as the first line of defense against numerous forms of disease. Knowing more about the immune system not only instills a greater appreciation for this impressive system but it may also provide insight into how to better support wellness.

The Importance of the Immune System

The immune system is a complex network of cells, organs, proteins, and tissues that span the entire body. The primary role of the immune system is to prevent and/or limit infection of harmful substances that cause illness. This is an essential factor in staying well. In fact, without a working immune system, we simply could not survive. If we did not have an immune system, assailants in the form of viruses, bacteria, parasites, faulty or dead cells, and other microorganisms would be free to infect the body and induce sickness. Fortunately, our bodies have access to powerful providers of immunity.

The Body’s Varied Forms of Immunity

Most people are born with some degree of immune function. However, at early stages, the immune system has not yet fully developed. Fortunately, our immune system has an impressive ability to strengthen itself over time through adaptive immunity.

When the immune system effectively eliminates an antigen or disease-causing substance, it remembers what it looked like and how it was able to defeat it. Retaining this information allows the immune system to respond more quickly and effectively if it ever encounters the same antigen in the future.

Over time, as the immune system’s catalog of diseases continues to grow, your body becomes increasingly capable of reacting to a wide range of illnesses. This is known as adaptive or acquired immunity and is usually why teens and adults tend to be sick less often than children.

In addition to adaptive immunity, there are two other forms of immunity that the body may employ: innate and passive immunity.

Innate immunity is what we as humans are born with. This includes physical defenses such as our skin and mucous membranes which help keep harmful pathogens out of the body.

Passive immunity can be described as a sort of temporary or borrowed protection from a source apart from our own body. An example of passive immunity is when a newborn acquires antibodies from the mother’s placenta or breast milk. This provides the temporary and often necessary protection from infections during the early stages of life. Certain medications can also provide passive immunity by temporarily bolstering the body’s defenses against specific pathogens.

How our Immune System Responds to Threats

A normal immune response is composed of four stages: recognition, activation, attack, and regulation.

Before being able to eliminate a threat, the immune system must first recognize the offending agent. This process is in part facilitated by leukocytes, also known as white blood cells. Leukocytes act like watchdogs, constantly circulating through the bloodstream and staying on the lookout for harmful substances. When leukocytes recognize a harmful substance, they multiply and send signals to activate other protective cells. Once the signal is received, these cells produce antibodies that target and eliminate the antigen.

Once the antibodies have eliminated the threat, the immune response must come to an end. Stopping the immune response at the appropriate time is essential. Insufficient immune activity may allow the antigen to remain in the body and cause sickness while a prolonged immune response can bring excessive inflammation that damages healthy cells and tissues.

Fortunately, most individuals have a fully functioning immune system that responds quickly and appropriately to potential threats to our health. However, certain conditions may cause the immune system to act irregularly.

The Three Major Forms of Immune Malfunction

As mentioned previously, the immune system is essential for our wellness. As such, it should come as no surprise that chronic immune malfunction can cause a wide array of issues. There are three primary forms of immune malfunction: immunodeficiency, autoimmune malfunction, and hypersensitivity.


Immunodeficiency is the result of one or more elements of the immune system malfunctioning. This causes the body to become less capable of combating illness. One example of immunodeficiency is AIDS, wherein patients may struggle to fight off the mildest of conditions. Immunodeficiencies may be inherited or caused by various factors including age, obesity, alcoholism, and drug use.

Autoimmune Malfunction

Normally the immune system is well equipped at discerning between harmful antigens and the body’s cells or tissues. However, in the case of autoimmune malfunction, the immune system incorrectly identifies healthy cells or tissues as a threat. This triggers the release of antibodies to attack the body, which can result in serious malfunction and chronic illness. Some of the most common forms of autoimmune disease are celiac disease, type 1 diabetes, rheumatoid arthritis, and autoimmune thyroid disease such as Graves’ disease and Hashimoto’s thyroiditis.


A hypersensitive immune system overreacts when exposed to certain substances. The severity of the response to certain allergens can damage healthy tissue and in some cases be life-threatening. A person who is hypersensitive to a specific substance may enter a state of anaphylactic shock when exposed to it. Common examples of this type of hypersensitivity are severe nut or shellfish allergies.

Fortunately, most forms of immune malfunction may be treated or managed through appropriate care.

Appreciating the Protective Properties of the Immune System

The immune system is one of the most important systems in the body. It acts as the first line of defense against harmful antigens that generate numerous forms of illness. Fortunately, we are all born with some degree of immunity and can build upon it or temporarily bolster its function through a variety of methods. Hopefully, with a better understanding of the immune system, you now recognize its integral role in health and overall wellness.


1. NIH. “Overview of the Immune System.” National Institute of Allergy and Infectious Disease.
2. [Internet]. Cologne, Germany: Institute for Quality and Efficiency in Health Care (IQWiG); 2006-2010 Nov 24 [Updated 2019 Nov 7]. “How does the immune system work?”

About Holtorf Medical Group

The Holtorf Medical Group specializes in optimizing quality of life and being medical detectives to uncover the underlying cause of symptoms, rather than just prescribing medications to cover-up the symptoms. We are experts in natural, prescription bioidentical hormone replacement and optimization, complex endocrine dysfunction, fibromyalgia, chronic fatigue syndrome and Lyme disease.

We’ve dedicated our practice to providing you the best in evidenced-based, integrative medicine that’s not only safe and effective, but provides measurable results.