give the chemical nature of antibodies and their mode of action
Answers
Antibodies, also called immunoglobulins, are proteins manufactured by the body that help fight against foreign substances called antigens. When an antigen enters the body, it stimulates the immune system to produce antibodies. (The immune system is the body's natural defense system.) The antibodies attach, or bind, themselves to the antigen and inactivate it.
Every healthy adult's body has small amounts of thousands of different antibodies. Each one is highly specialized to recognize just one kind of foreign substance. Antibody molecules are typically Y-shaped, with a binding site on each arm of the Y. The binding sites of each antibody, in turn, have a specific shape. Only antigens that match this shape will fit into them. The role of antibodies is to bind with antigens and inactivate them so that other bodily processes can take over, destroy, and remove the foreign substances from the body.
Antigens are any substance that stimulates the immune system to produce antibodies. Antigens can be bacteria, viruses, or fungi that cause infection and disease. They can also be substances, called allergens, that bring on an allergic reaction. Common allergens include dust, pollen, animal dander, bee stings, or certain foods. Blood transfusions containing antigens incompatible with those in the body's own blood will stimulate the production of antibodies, which can cause serious, potentially life-threatening reactions