Tools of the Immune System

The process by which the human body brings more immune system, and more nutritive activity to the site of an injury or infection is known as the inflammatory process, and the result is inflammation.

Let us consider two aspects of Inflammation.

Acute Inflammation: The quick action aspect of inflammation, 

Acute Inflammation isolates the damaged area, and mobilizes the various helpful elements to the site. When there is an injury, selective chemicals are needed to address the damage, as well as initiate the healing process.

Chronic Inflammation:

Chronic inflammation indicates the inflammatory processes have gathered to transform, and initiate healing of damages, but they are themselves out of proportion to the threatening agent and begin to produce more damage than the agent itself would have done.

Examples of Chronic Inflammation responses are the many types of allergies and autoimmune diseases. These would include Asthma, Rheumatoid Arthritis, Systemic Lupus Erythematosus, and Multiple Sclerosis, and Psoriasis.

Immune complex disorders are the result of antibodies complexed, or chemically integrated, with antigens, which then trigger the Complement System, the muscle of the immune system.

These disorders are made worse by the formation of antibodies against persistent, unresolved, antigens, and bring out the whole spectrum of inflammatory mediators which then exacerbate existing problems.

Basically, when microbes invade the human body, the immune system is activated to send antibodies to coat, or bind, them, rendering them unable to cause any problem. However, this action performs no useful function unless it activates, or enables, an effector mechanism. So then, the antibodies get to work right away, but depend upon an element produced in the Complement System to actually destroy the invader.

The complement system consists of some 30 proteins circulating in blood plasma. Most of them are inactive until cleaved by a protease, an enzyme that hyrolyzes peptide bonds in proteins and peptides, which, in turn, converts them into a protease. 

Thus many components of the system serve as the substrate of a prior component and then as an enzyme to activate a subsequent component. It is a cascade of action, where each level creates a difference that helps the next level to continue, and make another necessary change in the molecule, until it carries out its genetic destiny.

For a healthy immune system, we need the following elements.

1. Reactive Oxygen Species (ROS)

These are produced by activated phagocytes: macrophages and neutrophils. They are toxic for microorganisms but can also lead to tissue injury. ROS are described in detail on another page.

2. Histamine

The granules of mast cells are loaded with histamine and their exocytosis releases this potent mediator. Histamine increases the blood flow to the area and the leakage of fluid and proteins from the blood into the tissue space. Thus the quick release of histamine produces the redness and swelling associated with inflammation.

Macrophages, monocytes, and platelets are sources of several chemicals which trigger a cascade of other chemicals that stimulate yet others which then activate T cells. The T cells then initiate an adaptive immune response.

There are also endocrine influences which adjust blood pressure and induce fever,  The fever relaxes the smooth muscle walls of the arterioles lowering blood pressure and increasing blood flow to the tissue and makes the capillaries leakier, allowing blood components to enter the tissue space. These effects (like those of histamine) produce the redness, warmth, and swelling of inflammation.

Inflammation occurs when we have a wide variety of health problems. It is the alarm for the highly dynamic immune system to step in and use an enormous array of biochemical tools to help us to heal.