Antigen - Softcover

Please note that the content of this book primarily consists of articles available from Wikipedia or other free sources online. An antigen (from antibody generator) originally defined as any molecule that binds specifically to an antibody, the term now also refers to any molecule or molecular fragment that can be bound by an MHC molecule and presented to a T-cell receptor. "Self" antigens are usually tolerated by the immune system; whereas "Non-self" antigens are identified as intruders and attacked by the immune system. Autoimmune disorders arise from the immune system reacting to its own antigens. Similarly, an immunogen is a specific type of antigen. An immunogen is defined as a substance that is able to provoke an adaptive immune response if injected on its own. Said another way, an immunogen is able to induce an immune response, while an antigen is able to combine with the products of an immune response once they are made. The overlapping concepts of immunogenicity and antigenicity are thereby subtly different.