Antibodies are a class of proteins formed in the body in response to the presence of antigens, like foreign proteins and other compounds, which are bound to the antigen inactivating it. Though science may have done a lot of advancements in the understanding of molecular biology but still in quite a few cases it is still unable to implicate specific proteins with a disease.

By measuring the amount of the specific protein directly, it is possible to measure a true level of gene function. However, when one takes into consideration the large number of post-transnational modifications, human cells may contain a million or more different protein variants, any of which could be altered in disease making the task of analyzing all of them a huge task. Protein micro arrays or protein chips may have the solution to this problem. A slide could be spotted with thousands of known antibodies or peptides like a DNA micro array, a biological sample spread over the chip, and any binding determined. Protein chips can become a fast way to profile protein changes in disease.

Immunity to infection is due to the production of antibodies against specific proteins of disease causing organisms, and immunization is the process of giving these marker proteins, generally in an inactivated form, to stimulate the production of antibodies.

It is important fact to note that the food allergies caused also may be due to the production of antibodies against specific food proteins. Chemically the antibodies form a class of proteins known as the globulins. The body contains hundreds of thousands of different white blood cells called B lymphocytes, each capable of producing one type of antibody and each bearing sites on its membrane that will bind with a specific antigen.

The antibody molecule is made of four polypeptide chains ? of which two are identical light chains and the remaining two are identical heavy chains. The light chains have a variable portion that is different in each type of antibody and is the active portion of the molecule that binds with the specific antigen.

Antibodies combine with some antigens like, bacterial toxins, and for the purpose of neutralizing their effect; they remove other substances from circulation in body fluids; they bind certain antigens together and this process of binding is known as agglutination. These help to activate, complement, blood serum proteins that cause the damage by way of invading cells.