Structure and Types of Antigens

Structure and Types of Antigens

An antigen molecule may contain a number of similar group or different antigenic determinant. The figure 10.4 shows that a cell which contains different groups of molecules over the surface. However only the group a andd has been selected for antigen processing. Hence a andd are antigenic determinant. Normally antigens are multi determinant.

Types of antigen

Antigen possesses several unique molecular structures which can induce an immune response. Most antigens are proteins, nucleoproteins, lipoproteins,

glycoproteins, or large polysaccharides with a molecular weight greater than 10,000. To become an antigen the molecule must be relatively having a higher molecular weight. Large antigenic molecule posses many antigenic determinant per molecule. However the low-molecular-weight substance that can combine with an antibody but cannot induce the formation of antibodies are called as haptens. They can also initiate antibody response when they are combined covalently with a carrier molecule. Since antigens stimulate the immune response they are other wise called as immunogens.