The immune system works in collaborative symbiotic harmony with the body’s micro-biome and virome.

Briefly and simply, the immune system is a complex network of cells and proteins (cytotoxic T Lymphocytes, natural killer cells, anti-viral macrophages) that defend the body against pathogenic infection (or bacterial or viral proliferation) and systemic harm or imbalance.

The innate immune system provides initial ‘front line’ protection; however, while fast acting, it is non-specific in its action.

The adaptive immune system, on the other hand, instigates more specific honed responses, that are not always immediate.  Helper T Cells, for example, recognise pathogenic infected cells (foreign or toxic particles, or bacteria, or rogue cells such as cancer cells) and produce cytokines (a hormone-like protein) that attach to the infected cell, then triggers or stimulates specific responses by target cells, or anti-bodies.  Antibodies (a unique Y-shaped protein made and mutated within the body) are produced and employed by the adaptive immune system to recognise and neutralise pathogenic bacteria, other microbes or particles (antigen); once produced, these antibodies remain in the body for some time. The adaptive immune system records each pathogen ever defeated, so recognises it quickly again and destroys it. (Schrader 2015)

Primary immune system organs (lymphoid organs):

• Bone marrow (B cells)
• Thymus (T cells)

The thymus receives uncommitted lymphocytes from bone marrow and is actively engaged in T-lymphocyte proliferation.  The thymus is very large in babies but shrinks after puberty.

Secondary Immune System Organs

• Spleen
• Lymph nodes
• Tonsils and adenoids
• Appendix
• Mucosal associated lymphoid tissues (lungs, throat, nose and gut/bowel)

Immune System Cells

• B-lymphocytes are developed in bone marrow and produce a type of protein known as anti-bodies. They control infections by producing neutralising antibodies and antibody-dependent cellular cytotoxicity (cell-death), ‘fight’ pathogens and send signals that control the immune systems response to threats. They support the adaptive (acquired) immune system and produce a slow but long-lasting protective response.  For example, antibodies recognise and stick to foreign molecules that invade the body, thus, ‘branding’ or identifying the invading molecules – more and more antibodies are then produced until the invader is defeated.  Antibodies (or sentinels) set up a future recognition mechanism.

• Plasma cells, found in the watery part of blood, are white blood cells that originate in the lymphoid organs as B cells; differentiated B-lymphocytes that are capable of secreting immunoglobulin or antibodies (in response to contact with antigens – toxins, chemicals, bacteria, viruses or other substances that come from outside the body), they also play a significant role in the adaptive immune response. Some body tissues, including cancer cells, have antigens on them that can cause an immune response.

• T-lymphocytes, also develop in bone marrow, instigate a fast-acting immediate defensive response. They ‘fight’ infection.  Part of the innate (natural) immune system, T-lymphocytes distinguish ‘self’ from ‘other’ and manage, control and curtail exaggerated immune responses. The skin barrier forms part of the innate immune system.  Sneezing, inflammation and itching are examples of innate immune system reactions. (T-lymphocytes are supported by intake of a fresh healthy diet, vitamin C, vitamin D and sunshine).

• Large lymphocytes are natural killer (NK) cells that limit the spread and subsequent tissue damage caused by cancers and microbial infections (these cells secrete deadly chemicals which make the infected cells content leak out).  Natural killer cells can develop and mature in the bone marrow and secondary lymphoid tissues (including tonsils, spleen, and lymph nodes).

• Phagocytes surround (ingest) and kill or eliminate micro-organisms, foreign substances or particles, and apoptotic (self-destructed) cells. They are scavengers which constantly move around to remove dead cells and foreign bodies such as pathogenic microbes.  They are found in blood (neutrophils and monocytes), bone marrow (macrophages, monocytes, sinusoidal cells and lining cells), bone tissues (osteoclasts), gut and intestinal Peyer’s patches (macrophages), tissue dendritic cells (found in bone marrow and the thymus), and mast cells (found in connective tissue cells throughout the body).

The role of blood cells

• White blood cells (leukocytes) found in the liquid (plasma) part of blood are normally inactive, but when ‘switched on’ by contact with invading bacteria will destroy bacterial cells to curtail infection and disease.

• Red blood cells (erythrocytes) transport oxygen around the body.

Further protective dynamics of immunity

• Tough and flexible with a surface of dead skin cells packed with keratin (a fibrous structural protein), the skin provides a protective barrier and stops invasion of microbes.

• The lining of the mouth, throat and lungs, and reproductive system, is constructed from layers of cells that secrete large amounts of watery fluid known as mucous. Mucous traps invading microbes.  For example, the anti-bacterial enzyme, lysozyme, present in mucous, helps keep micro-organisms under control and aids the lung to expel foreign particles.

• Stomach acidity caused by hydrochloric acid secreted by the stomach lining destroys harmful pathogens.

How the body repairs itself: 

• When bones break, new cells are formed in a blood clot (coagulated blood cells) at the broken bone ends – these cells transform into cells that knit the bones together again.

• Replaces worn out or dead cells. In skin tissue, for example, the dead outer layer is replaced by new cells, formed in the living lower layer where rapidly dividing cells produce a constant supply of replacement-cells.

• Repairs the wall of damaged blood vessels. For example, a quick-setting temporary patch made of platelets is formed; then, a longer-term repair is made with fibrin, which is an insoluble blood protein; finally, a permanent repair in the vessel wall is made via new cell growth.

• Dislocated or sprained joints are immobilised by fluid in tissues (oedema) and held in place while the injured site repairs.

• Severed nerves join up to restore feeling and sensation.

• Brain neurons re-wire to minimise damage.