Antigen: An antigen is a foreign molecule or

An antigen is a foreign molecule or substance that triggers an immune response in the body, leading to the production of antibodies. What is Antigen ? Definition of Antigen : Antigen is a substance that causes the body to produce antibodies to fight it off. Antigen can be proteins, polysaccharides, lipids, or nucleic acids. When antigens enter the body, they are detected by immune cells, leading to the production of antibodies or the activation of T-cells. Antigens can originate from pathogens like bacteria, viruses, fungi, or other foreign substances such as toxins. They help distinguish self from non-self, helping the ... Learn about antigens. Get the antigen definition and learn about the types, functions, and types of tests in immunology. Antigen It is a substance usually protein in nature and sometimes polysaccharide, that generates a specific immune response and induces the formation of a specific antibody or specially sensitized T cells or both. Antigens are “targeted” by antibodies. An antigen may be a substance from the environment, such as chemicals, bacteria, viruses, or pollen or may also be from inside the body. In general, two main divisions of antigens are recognized: foreign antigens (or hetero-antigens) and ...