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Immunology is the study of the body’s protection from foreign invading microbes or substances and the body’s response to such evasion. Microbes are disease causing organisms. Examples are bacteria, viruses, fungi. Not only microbes but particulate matter such as pollen, or dust inhaled into the body can constitute foreign invasion. Once these pathogens break through the body’s barriers and enter the body cells and tissues, they elicit a response from the body. The invaders are referred to as antigens or immunogens.
The immune system of the body is a network of cells, tissues and organs that work together to defend the body against attacks. All cells of the immune system are derived from the bone marrow. The bone marrow produces a number of cells notable of which include B-cells, T cells and macrophage cells among others. The T cells once produced migrate to the thymus, an organ in the body, where they mature and are finally released into the blood stream. Other organs of the body playing a role in the immune system include the spleen which filters blood and has B cells, T cells and macrophages. The lymph nodes also filter lymphatic fluids and also contain B, T and macrophage cells.
These cells have profound functions in the immunological process: B cells produce antibodies towards specific antigens to neutralize their effect. Antibodies are soluble proteins that bind to antigens. Once the immune cells receive signals of an attack they rally round the target cell. These signals are secretions of chemicals. T cells do not secrete antibodies but aid the binding of antibodies on the surfaces of the antigens and their consequent destruction. Once antibodies are bound to the antigen molecule, phagocyte cells eat up the invader and the immunological process is over.
Diseases occur when the infection is high or the virulence overwhelms the body’s ability to fight the pathogen, or when the body’s immune system become compromised (Linemeyer). People who recover from some infections do not get them any longer. Such people are said to have acquired immunity against that particular disease (Hepatitis B Foundation, 2008). This happens through agency of T and B cells, some of which transform into memory cells, once activated. The next time a person meets up with the same antigen, the immune system has its arsenals in memory ready to destroy.
Immunity can also be affected by inherited genes: some people react forcefully others feebly towards the same antigen. Immunization is the deliberate introduction of micro organisms, or part of treated micro organisms into the body so as to provoke immune response but not a full blown disease. Immunization is achieved through vaccines. Vaccines have been used for over a hundred years to control diseases such as small pox, polio, measles and many more.
In fact small pox has been eradicated through vaccination. Immunity can be transferred from mother to child through birth and through nourishment by breast feeding. Serum injection with antibodies can transfer immunity from one person to the other. Immune system players, T and B cells are able to discern between self and non self that is, they do not attack the cells of their own body, but foreign invaders. This attribute is referred to as the body’s immune tolerance, however, sometimes the body manufactures, T antibodies directed against self. These misguided cells give rise to autoimmune diseases, an example of which is a form of diabetes where a misguided T cell attacks certain cells in the pancreas.
When an immune system loses one or more of its parts, gives rise to immune deficiency disorder. These disorders can be inherited, acquired or produced by side effects of drugs. Some children are born with defective system. AIDS is an immune deficiency disorder caused by a virus, HIV that infects immune cells. HIV destroys T cells. The virus can hide itself for a long time in immune cells weakening them over time to develop into AIDS.
The discipline of Immunology is an emerging field. Today, organ transplants are possible, genetic engineering of prolific genes for use in medicine, agriculture and industry is emerging. Gene therapy holds promise for treating difficult diseases.