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Non-Self Is Not Non-Sense

Non-Self Is Not Non-Sense

Although the majority of the human immune system's function remains a mystery, it has been fairly well determined that both a primitive and modern component coexists within it. Fortunately most people are blessed with active, competent immunity. Although one may have a suitable number of white blood cells circulating in the blood, some of the cells may have an inexplicable functional deficiency that prevents them from operating properly. I remember some years ago a local television journalist followed several Shelby County Pot-Hole repair crews for a week. The report showed there were enough men and women to get the job done, but the workers goofed off most the day leaving the pot holes in disrepair. We do not want our immune systems playing around like a Shelby County Pot-Hole repair crew.

The modern system is comprised of B and T-lymphocytes and Natural Killer Cells. These three types of cells attack infections differently. T-lymphocytes (T-Cells) bring about cell mediated immunity. Essentially T-Killer cells attach to cells harboring foreign intracellular invaders and kill the cell as well as the contents within it. B-lymphocytes bring about humoral or antibody mediated immunity. B-cells have the ability to differentiate and generate antibodies, which are relatively large proteins that bond to some specific feature of an invading pathogen. The antibody's specificity is critical. The antibody usually has a unique shape and will conform perfectly to the shape of a distinctive feature of the invader. The antibody fits a portion of the pathogen like a glove. Once the infectious agent is bound up by an antibody, it is rendered immobile and targeted for destruction.

Monocytes (primitive system) have the ability to diversify into large macrophages and ingest large amounts of foreign material. These phagocytes can present fragments of the devoured material to T-Helper cells by extending specific fragments from its cell membrane. As it shows off the protein, the macrophage also secretes a cytokine called IL-1 which stimulates the T-Helper cell to alter its membrane to recognize the fragment: specific antigen receptors develop on the T-Helper cell's surface (TCR). T-Helper cells have CD4 receptors on their surface and are also called CD4+ cells.

T-Helper cells release IL-2 which triggers the proliferation of T-Killer cells. These specialized T-lymphocytes have CD8 surface receptors (also known as CD8+ cells). These cytotoxic T-cells attack and destroy infectious parasites or the cells that harbor infectious parasites, bacteria and viruses. The HIV virus knocks out T-Killer cells and by doing so makes humans profoundly immune compromised. While fighting an infection, the T-Helper cell also secretes B-Cell Growth Factor which triggers differentiation and proliferation of more B-Lymphocytes (B-cells). B-cells produce antibodies against the same infectious agents to which the T-Killer cell is being sensitized. It is a very efficient and sophisticated system.

There are many types of T-cells. A third common cell is the T-Suppressor cell. It has a CD3 receptor on its surface (CD3+ cell). Very little is known about them. They seem to down regulate the immune response. In addition, memory T-cells exist. They last a long time. When the same invader returns or reactivates from a latent state, memory T-cells mediate a quicker response and sometimes act before any real signs of infection occur.

B-cells primarily target extra-cellular agents and are activated by recognition of a specific antigen (foreign material). They are co-stimulated by cytokines from the T-Helper cells (CD4+). They can differentiate into plasma cells that secrete antigen-specific antibodies a rate of millions of molecules per cell per second. Plasma cells can live up to a week making billions of antibodies. Memory B-cells remain behind after an infection is over to respond quicker to re-infection.

Natural Killer Cells (NK) do not require prior exposure or sensitization to act. They do not have surface antigen receptors. They must contact a pathogen to eradicate it. It is thought that their recognition of self from non-self is mediated by the presence or absence of major histocompatibility molecules (MHC). MHC molecules are surface markers on all of the body's cells except red blood cells. They are unique glycoproteins recognized by the body's immune system as self.

NK cells attack non-self and any foreign invader that lacks MHC antigens are seen as non-self. MHC molecules are important in accepting or rejecting transplanted organs or tissues from donors. That is why potential donors are screened prior to organ donation to assure the best MHC match prior to transplantation.

The complex diversity of our immune system is deep. I think scientists (specifically immunologists) have an inadequate truth about how the immune system functions and what constitutes a healthy immune response. They have identified only a small portion of the endless family of cytokine molecules that control immune behavior as well as those simple chemotactic factors that stimulate and depress the growth of stem cells and cancer. They have yet to elucidate all of the roles that Neutrophils, Monocytes and Lymphocytes play in mediating acute or chronic infection as well as how they cause the diverse array of autoimmune diseases. There is a primitive and modern system that functions in concert to fight infection and moderate inflammation.

It is amazing to me that unproven contemporary immune theory has transformed from a possibility into the unsubstantiated dogma of the modern physician. I think the body's immune function has figured out the non-self better than most physicians have sorted out the non-sense associated with immune system theory. What we know is that the immune system is comprised of a primitive and diversified modern system, both functioning in concert to fight infection and moderate inflammation.

That's what we know. That's what it boils down to. Primitive and Modern together. Fractal forever.

Posted by Amanda Sanders at 8:34 AM
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