Antibody

The definition of antibody are proteins in the blood that can combine with foreign substances (antigens) and assist in their removal from the body. The production of agens and is part of the immune response against pathogens and is important in recovery from the infectious diseases caused by bacteria or viruses.

The continued presence of antibody molecules in the blood after an infections is one reason for the long lasting Immunity to many diseases. Individual antibody molecules have a high affinity for one particular antigen, but the body produces millions of different antibodies.

Another defensive function of antibodies is the protection of the new born infant. The antibody received across the placenta from the mother protect the newborn until it has developed its own antibodies. Antibodies are also present in the mother's milk and can be absorbed during breast feeding. In many mammals this is the newborn's only antibody source.