The Immune System: Our Natural Defence

by Deep, Radi, and Mithu on November 11, 2015

in General Health

Immune System-ChartWHAT IS THE IMMUNE SYSTEM?

How many of us are aware of the marvellous and intelligent inner world we carry within our bodies? Outmatching any past or present day government system, this world is efficiently organized to take in and carry nutrition to all of its parts, efficiently dispose of garbage, cooperate with all of its members, and defend itself with brilliant first, second, and third line strategies. It does all this quietly and efficiently, not asking for recognition or applause, only for sensible eating habits, the avoidance of toxins as far as possible, and a healthy and natural lifestyle. Here we will deal with one of its functions: its defence or immune system (IS).

Some of us seem to think of the IS as a particular organ defending the body. But in truth, it is composed of a variety of proteins and specialized cells  “organized” and “educated” to recognize foreign pathogens and overcome them. It involves an amazing collaboration between cells and proteins to do this, and these are dispersed throughout the body in order to rapidly respond to attack.

TWO CATEGORIES OF IMMUNE SYSTEM RESPONSE:

There are two categories of immune system response: the innate IS and the adaptive IS. The innate IS is what we are born with, and is a system complete in itself, not requiring additional training to respond rapidly to infection. It involves several lines of defence, the first being our skin which is a waterproof barrier, preventing pathogens from entering the body. The nose and the mouth are body cavities lined with mucus membranes which trap bacteria in a sticky mucus. Acidic gastric juice produced in the stomach kills off much of the bacteria in food, while saliva helps to reduce bacteria in the mouth and washes them off your teeth. If pathogens manage to break through this first line of defence, they are met with a second battalion of specialized white blood cells or chemicals released by tissues and cells.

The adaptive IS, or immunity, develops as we grow and involves T cells and B cells that require “educating” so as not to attack our own cells. The advantages of the adaptive IS are its long-term memory and the ability to recognize new germs. Central to both IS systems is the ability to distinguish between invading pathogens and our own cells. The innate system’s rapid response to infection is our first line of defence, and this response alerts and triggers the adaptive system which may take several days to become activated. Both systems are functional at birth, but the adaptive system needs educating and experience, as well as a built-up memory bank that forms throughout life with each exposure to infection. This stored memory enables it to respond to similar infections with a stronger and more rapid response.

T CELLS AND B CELLS

Lymphocytes are specialized immune system cells composed of T cells and B cells. Produced from primitive stem cells in the bone marrow, where all cells of the IS originate, they begin their lives and development there. While the B cells continue to develop and mature in the bone marrow, the T cells migrate to the thymus where they are “educated” to become mature T lymphocytes. These cells have the important function of producing antibodies (immunoglobulins or gammaglobulins).

Mature B cells are distributed in the bone marrow, lymph nodes, spleen, parts of the intestines, and the blood stream. When foreign bodies are encountered, they respond by turning into plasma cells, with some of them becoming memory cells. The plasma cells produce antibodies which find their way into the tissues, respiratory and intestinal secretions, the blood stream, and even tears. Every foreign antigen has an antibody molecule designed to lock into it. B cells have the ability to produce a very extensive variety of these molecules. The antibodies attach to the “foreigner,” setting off a complex chain of actions that involve other components of the IS to eventually destroy the germ.

There is an extensive variety of T cells in the body that enables them to respond to almost any pathogen. They vary in function, some being “killer” or cytotoxic cells, and others helper and regulatory cells. Killer T cells attack and destroy virus-infected cells. Viruses can only survive and multiply within our cells where they are hidden from the immune system. So the infected cell releases cytokines to alert the body in order to prevent infection of other cells. Killer T cells circulating in the blood stream rush to the site where they kill the infected cell. This process involves the sacrifice of the infected cell and many other cells. During the destruction process, the T cells also instruct the B cells  to manufacture antibodies that can deal with another exposure to the same virus. Memory T cells are also produced for the same purpose.

With bacteria, our skin and internal mucus membranes effectively defend against infection. But if damaged due to injury or disease, bacteria can enter the body. When they do, they get coated with “complement” (we explain what this is later) and antibodies, and the relevant immune cells then engulf and destroy them.

MAJOR ORGANS OF DEFENCE

The major organs of defence in the immune system are:

  • Bone marrow, which is the “womb” where all cells of the immune system begin their life and development.
  • Thymus: this organ is located in front of the windpipe or trachea. Immature T cells leave the bone marrow and locate themselves in the thymus where they are educated to become mature T lymphocytes.
  • Tonsils: these are collections of lymphocytes located in the throat.
  • Lymph nodes are collections of B and T lymphocytes throughout the body. These cells get together in lymph nodes to communicate with each other.
  • The liver: this is one of the main bastions of the immune system and is responsible for synthesizing proteins of the “complement” system.  This system is composed of 30 blood proteins functioning in an orderly way to defend against infection. It also contains large numbers of phagocytic cells which ingest bacteria in blood that passes through the liver.
  • The spleen: this order is composed of a collection of T and B lymphocytes and monocytes. It filters the blood and provides a space for organisms and cells of the immune system to interact.
  • Blood: is a circulatory system carrying cells and proteins of the IS to all parts of the body.

We cannot go into more detailed information on the various specialized cells and their functions in the IS. However, the information presented above serves to give an idea of the marvelous strategic cooperation involved in the workings of our immune system. But in our day and age, the unnatural toxins that we imbibe in our food and water, and even the air we breathe, combined with the stress of our lifestyles, puts an enormous stress on the body. Some of the disorders associated with a malfunctioning IS are: HIV/AIDS, lymphoma, myeloma, leukemia, cancer, allergies, and several other serious health conditions.

Apart from a healthy diet, fresh air, exercise, and stress relieving activities, our IS may need supplementary help in order to function well.

Please visit our product page on “Help for the Immune System” to learn about key supplements that can strengthen your immune system.

References:

Dr. Rachel Hoad-Robson. n.d. “The Immune System” (Document ID: 12484 v3). Accessed at: www.patientinfo/health/the-immune-system.

Immune Deficiency Foundation USA. 2013. “The Immune System and Primary Immunodeficiency.”  Extracted from The IDF Patient and Family Handbook for Primary Immunodeficiency Diseases (fifth edition). Accessed at: http://primaryimmune.org/about-primary-immunodeficiencies/relevant-info/the-immune-system/

 

 

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