The Immune System: Basic Overview

The immune system. This term is frequently used to describe one of the major systems of the body. There are different ways to look at its actual components. In some circles the entire body is considered the immune system because everything influences immunity. In the wholistic approach, the whole body - the skin, digestion, hormones, circulation, etc. all play a role in keeping us healthy. 

The immune system has two roles:  to kill and to remember. Pathogens release certain chemicals and proteins that our immune system recognizes as not part of us which triggers a kill response. Once this occurs the system “remembers” and we can reduce the impact of future attacks of a similar pathogen and thus have “immunity.”

This parallels the two main parts to the immune system. The primary or innate immune system and the secondary or acquired immune system. The innate immune system is for immediate response to pathogens. The acquired immune system develops after. It creates highly specific antibodies for foreign (“not self”) or body (“self”) proteins (antigens). 

The lymphatic system plays a major role in the immune response. The primary organs of the lymphatic system are the thymus gland and the bone marrow. The secondary organs are the lymph nodes, spleen, tonsils, liver, Peyer’s patches in the small intestines, and appendix.  

The thymus gland is located beneath the breastbone and is the place where T cells mature. T-cells are a form of white blood cells that recognize and attach to foreign molecules (antigens).  White blood cells are made in the bone marrow. Bone marrow also produces red blood cells and platelets. White blood cells include lymphocytes, neutrophils, monocytes, eosinophils, and basophils. 

There are two types of lymphocytes – the previously mentioned T cells and B cells. B-cells make antibodies. These are chemicals that latch onto foreign substances inactivating them or marking them to be destroyed by other immune cells. Natural killer (NK) cells are a type of T-cell - the first line of defense for the body versus an infection. Lymphocytes migrate to areas of inflammation throughout the inflammatory process. Remember that infection produces inflammation.

Phagocytes are immune cells that engulf and digest foreign particles. They follow the lymphocytes into battle. The lymphocytes have marked the invaders for destruction. The phagocytes complete that task. The most important phagocytes are neutrophils and monocytes. Neutrophils are the first to respond to an infection. They will be elevated at the onset of an infection and decrease as the body fights the infection. They are the primary defense against microbial infections and respond to inflammation. 

Monocytes are the body’s second line of defense against infection. They will remove dead cells, microorganisms, and other waste materials from circulating blood. Monocytes tend to be elevated towards the end of the infection. They will stay elevated due to high levels of inflammation, during an extended recovery from an infection, and in cases of extended infection such as parasitic infections.

Eosinophils help to remove and breakdown the by-products of protein catabolism. They can ingest antibody-antigen complexes and are active in the later stages of inflammation. They are not effective against bacteria, but do respond to allergic and parasitic issues. Eosinophils will remain elevated in cases of intestinal parasites or food or environmental sensitivities. They are phagocytes that contain histamine, heparin, and serotonin.

Basophils also contain histamine, heparin, and serotonin. They play an important role in the inflammatory process by releasing heparin and other substances to prevent clotting in the inflamed tissues. They will often be elevated in cases of continued inflammation and allergies.

On a side note: Most blood tests will include what is known as the WBC (white blood cell count) and differential. The differential is the composition by type of white blood cell and adds up to 100%. Many times a client will be told that their blood test results are “normal.” However, in truth, their lab results are far from optimal. When taking a closer look at a client’s WBC and differential I often find the patterns of either acute or chronic infection or inflammation which supports the findings of my nutrition response testing.

Lymph is a fluid that contains lymphocytes, proteins and some fatty molecules formed from the fluid around the body cells.  Its function is to filter this material and return it to the blood stream.  The lymph removes waste materials from cells, so they can be disposed of properly by the body. The material moves through lymphatic capillaries and lymphatic vessels on its way back to the circulatory system. The lymph nodes are where the lymph is filtered and purified. 

The spleen filters the blood and lymph. It removes old red blood cells and destroys bacteria. The tonsils protect us against bacteria that enters via the nose and mouth. The liver produces half of the lymph in the body and stores and detoxifies blood. The Peyer’s patches monitor intestinal bacteria populations and prevent the growth of pathogenic bacteria. The appendix makes antibodies. 

Following is a basic example of how the immune system works to defend the body against a virus with a four-step process.

1.      The invading virus is detected by white blood cells called macrophages.  These cells are also known as the “frontline defender”.  As they encounter a foreign organism such as a virus, they begin to destroy the antigens or toxins produced by the virus.  These activities are noticed by helper T-cells.  They have identified that the macrophages need more help, so they signal the spleen and lymph nodes to produce additional cells to help fight the infection.

2.      The full involvement of the immune system.  The spleen and lymph nodes are producing Killer T-cells and B-cells.  Killer T-cells begin to multiply and arrive to fight the invading virus.  At the same time B-cells produce antibodies which are effective at targeted a specific invader.

3.      Fighting off the virus.  By this time the virus is also doing its own fight for survival.  It has entered some of the body cells and is replicating and multiplying on its own.  The Killer T-cells are killing the infected cells and the antibodies are working to prevent further growth of the virus.

4.      The virus has been contained and the thymus sends out suppressor T-cells to slow down the immune response.  At the same time Memory cells are recording specific information about the virus, so that should it appear again, the body will be able to fight it more efficiently and effectively.

The above are the basic mechanics of the immune system. We tend to think of our immune system as fending off invading foreign substances that create an infection - such as bacteria, viruses, parasites, and fungus. However, it is important to understand that other factors have great influence on our immune response. The wholistic approach. These factors include: food and nutrition, the environment, and stress.

The food we eat is critical. Foods that we are allergic to or that we have sensitivities to will produce an inflammatory response.  This turns on the immune system, utilizing resources that may otherwise have been required to fight a pathogen. Sugar is known to depress the immune system for up to five hours after being consumed. And, general nutritional deficiencies make it easier for pathogens to invade our body and reduce the effectiveness of the immune system. Our susceptibility to secondary infection is greater and recovery will be slower after infection or illness.

Environmental toxins are known to compromise the immune system, particularly exposure to heavy metals such as: Mercury (found in dental amalgams, fish); Lead (found in drinking water, paint, pollution, and pipes); Cadmium (from cigarette smoke, shellfish, and industrial waste); Aluminum (in antacids, antiperspirants, pots, foil, and water); and Arsenic (found in rice, tobacco smoke, pesticides, and glues). Again, dealing with environmental toxins distracts the immune system from pathogens. It is quite common to see heavy metal toxicity accompanying pathogen activity.

Signs of a toxic body include: fatigue, lethargy, depression, headaches, allergies, muscle aches, chronic infections, frequent colds, sluggishness, nervousness, irritability, sensitivity to perfume and other odors, and joint pains.

Once the body begins to show signs of toxicity, the immune system is over-burdened and autoimmune disorders begin to occur. Did you know the current list of autoimmune diseases is now over 150 and continues to grow? We can truly say there is an autoimmune epidemic underway in the United States. We all know at least one person who suffers from an autoimmune condition.  In most cases they are offered little help from traditional medicine. The best case is to “manage” it to keep the symptoms as reduced as possible. There is never any mention of a possible reversal of the condition. Fortunately, many natural/holistic practitioners across the country are having success in preventing and reversing autoimmune conditions every day. For further reading please read the article Natural Solutions for Preventing and Reversing Auto Immune Conditions. Click here: http://brwellness.com/nutrition-news/?p=742.

Bernard Rosen, PhD is a Nutrition Consultant and Educator. He works with individuals, groups, and at corporations to create individualized nutrition and wellness programs. His office is in Mequon, WI. To learn more or to schedule an appointment, e-mail at bernie@brwellness.com, call (262) 389-9907 or go to www.brwellness.com.