Properties and Function of different classes of Antibodies
Antibodies are glycoproteins produced in membrane-bound or secreted form by B lymphocytes in response to exposure to foreign structures known as antigens. The human immunoglobulins are a family of proteins that confer humoral immunity and perform vital roles in promoting cellular immunity. There are five classes of antibodies or immunoglobulins termed immunoglobulin G (IgG), IgM, IgA, IgD and IgE. All these classes have the basic four – chain antibody structure but they differ in their heavy chains termed γ, μ, α, δ and ε respectively. The antibodies are the gamma globulins. Antibodies are often referred to as “first line of defense” against infection. The most important function of antibodies is to confer protection against microbial pathogens. Antibodies confer protection in the following ways: They prevent attachment of microbes to mucosal surfaces of the host. They reduce virulence of microbes by neutralizing toxins and viruses. They facilitate phagocytosis by o