Our body is not defenseless against the bacteria, viruses, protozoa and other impacts. It knows how to deal with the "enemies" that try get inside. Defenses are called immunity. Immunity is divided into cellular and humoral. Antibodies are a part of humoral immunity (Medicine 2001).

Antibody (immunoglobulin) is soluble glycoproteins that are present in blood serum, tissue fluid, or on the cell membrane that recognize and bind antigens. Immunoglobulins are synthesized by B-lymphocytes (plasma cells) in response to foreign substances defined structure - antigens. Antibodies are used by the immune system for identification and neutralization of alien objects - such as bacteria and viruses.

Immunoglobulin of all types is bifunctional. This means that the function of any type of immunoglobulin is to recognize and bind the antigen, and then increase the killing of immune complexes formed as a result of activation of effector mechanisms.

So, one area of the antibody’s molecule (Fab) determines its antigenic specificity, and the other (Fc) presents effector functions: binding with the receptors that are expressed on cells of the body or binding with the first component (C1q) of the complement system to initiate the classical pathway of cascade complement (Zanetti 2000).

Antibodies have the ability to interact with the antigens that caused their formation. After the combination with the antibody, the antigen is derived from the body. The appearance of antibodies against infection in patient's blood means the appearance of immunity to this infection.

The antibodies appear in the serum of immunized person as a result of specific reactions to the injection of antigens. The contact of organism with the antigen causes an increased synthesis of antibodies in the immune system cells. There are antigen-binding sites in the surface of antibodies, the configuration of which corresponds with the three-dimensional structure of the antigenic determinat groups (The Biology Project 2000).
Antibodies are our protectors that prevent bacteria and viruses easily penetrate into our body.

Work Cited:

Medicine. 2001. Definition of Antibody. Retrieved from
The Biology Project. 2000. Antibody Structure. The University of Arizona. Retrieved from
Zanetti, Maurizio., Capra, J. Donald., Capra, Donald J. 2000. Antibodies. Medical. p. 114. Print.

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