Difference between Antigen and Antibody
Antigen and antibodies are two very different molecular entities. Simply put, an antibody (Ab), also known as immunoglobulins, is a glycoprotein that is produced in response to and counteracts a particular antigen. On the other hand, an antigen (Ag) is a foreign substance (generally harmful) that the body recognizes as foreign and that induces an immune response, thus stimulating the production of antibodies. Difference between Antigen and Antibody
Below, you will find a comparative table where we expand the details of the differences in these two elements
| Antigens | Antibodies |
|---|---|
| Also known as immunogens | Also known as immunoglobulins |
| Antigens are usually lipids. However, they can also be proteins, carbohydrates, and nucleic acids. | All antibodies are proteins |
| Antigens cause allergic reactions or even illness | Protects against the effects of the antigen either by lysis or immobilization of the particle |
| Epitopes are regions of the antigen where it interacts with antibodies. | Paratopes are variable regions of an antibody that bind to an epitope. |
| Antigens originate outside the body. | Antibodies always originate within the body |