Question

Research the major ways the immune system is compromised daily and discuss how this affects overall health. Consider the types of cells in the immune system and their function. How can altering these cells lead to disease? Include citation.

Answer 1

The immune system is being compromised daily and provides perfect health by some mechanisms.
1. Phagocytosis of bacteria and other invaders by white blood cells and cells of the tissue macrophage system
2. Destruction of swallowed organisms by the acid secretions of the stomach and the digestive enzymes.
3. Resistance of the skin to invasion by organisms.
4. Certain chemicals and cells in the blood that attach to foreign organisms or toxins and destroy them such as lysozymes, basic polypeptides, complement complex and the natural killer lymphocytes

This type of immunity is called innate immunity , and it makes the human body resistant to such diseases as some paralytic viral infections of animals.

In addition to this, there is acquired type of immunity, which is achieved by formation of antibodies and activated lymphocytes that attack and destroy the specific invading organism or toxin. Immunizations are part of acquired immunity.The cells involve in this type of immunity are the B cells and the T cells. B cells provide humoral immunity by developing circulating antibodies, which are globulin molecules in the blood plasma capable of attacking the invading agent. T cells provide cell mediated immunity by formation of large numbers of activated T lymphocytes that are specifically crafted in the lymph nodes to destroy the foreign agent.Both of this cells are activated only by the invading antigens in the body.

There are three types of T cells 1)T-helper cells, 2) cytotoxic T cells, and 3) suppressor T cells.

The most abundant is the helper T cells , they help in the function of immune system by forming a series of protein mediators, called lymphokines, that act on other cells of the immune system, as well as on bone marrow cells. Among the most important lymphokines secreted by the T-helper cells are the Interleukin-2,3,4,5,6,Granulocyte-monocyte colony-stimulating factor and Interferon-γ.
The cytotoxic T cell is a direct-attack cell that is capable of killing microorganisms and, at times, even some of the
body’s own cells. so  these cells are called killer cells. They secretes hole-forming proteins, called perforins, that literally punch round holes in the membrane of the attacked cell. Some of the cytotoxic T cells are especially lethal to tissue cells that have been invaded by viruses because many virus particles become entrapped in the membranes of the tissue cells and attract T cells in response to the viral antigenicity. The cytotoxic cells also play an important role in destroying cancer cells, heart transplant cells, or other types of cells that are foreign to the person’s
own body. The suppressor T cells functions to prevent the cytotoxic cells from causing excessive immune reactions that might be damaging to the body’s own tissues. For this reason, the suppressor cells are classified, along with the T-helper cells, as regulatory T cells.They plays an important role in limiting the ability of the immune system to attack a person’s own body tissues, called immune tolerance..

Sometimes people lose immune tolerance of their own tissues. This phenomenon occurs to a greater extent the older a person becomes. It usually occurs after destruction of some of the body’s own tissues, which releases considerable quantities of “self-antigens” that circulate in the body and presumably cause acquired immunity in the form of either activated T cells or antibodies. specific diseases that develop from autoimmunity are rheumatic fever, a type of glomerulonephritis, myasthenia gravis, SLE etc.

The lymphocytes are located most extensively in the lymph nodes, but they are also found in special lymphoid tissues such as the spleen, submucosal areas of the gastrointestinal tract, thymus, and bone marrow. In people who have a genetic lack of lymphocytes or whose lymphocytes have been destroyed by radiation or chemicals, no acquired immunity can develop. Within days after birth, such a person dies of fulminating bacterial infection unless treated by heroic measures. So it is clear that the lymphocytes are essential to the survival of the human being.