Difference between Antigen and Antibody
Antigens and Antibodies can be differentiated by the following:
| Feature | Antigen | Antibody |
|---|---|---|
| Definition | A substance that triggers an immune response and can stimulate the production of antibodies. | Proteins produced by the immune system in response to the presence of an antigen. |
| Origin | Can be derived from pathogens (bacteria, viruses), foreign substances, or even self-substances in certain autoimmune conditions. | Produced by B cells (a type of white blood cell) in response to the presence of antigens. |
| Nature | Antigens can be proteins, carbohydrates, lipids, or nucleic acids. | Antibodies are proteins (immunoglobulins) with specific structures that recognize and bind to antigens. |
| Function | Initiates and elicits an immune response. | Acts against antigens by binding to them and neutralizing or marking them for destruction by other immune cells. |
| Recognition | Recognized by the immune system as foreign or non-self. | Specifically binds to the complementary antigen that triggered its production. |
| Diversity | Diverse; various antigens can elicit an immune response. | Highly diverse; numerous types of antibodies, each specific to a particular antigen. |
| Specificity | Generally not highly specific; the immune system can recognize a broad range of antigens. | Highly specific; each antibody is designed to recognize and bind to a specific antigen. |
| Production | Produced by the body or introduced through vaccination. | Produced by B cells through a complex process called somatic recombination. |
| Role in Immunity | Initiates the immune response by triggering the production of antibodies. | Essential for the immune system’s ability to recognize, neutralize, and eliminate pathogens or foreign substances. |
| Examples | Pathogen proteins, toxins, allergens. | IgG, IgM, IgA, IgD, IgE (classes of antibodies). |
| Size and Structure | Variable depending on the type of antigen. | Y-shaped structure; composed of two heavy chains and two light chains. |
| Half-life in Blood | Antigens may persist for a shorter duration. | Antibodies can circulate in the bloodstream for an extended period |
Antibody – Structure, Functions, and Types
Antibody proteins are Y-shaped proteins that recognize and neutralize pathogens in the immune system. Antibodies play an important role in immune defense. Antibody structure consists of four polypeptide chains—two heavy and two light—and they form a distinctive structure with variable and constant regions.
There are five main types of antibodies: IgM, IgG, IgA, IgD, and IgE, each having a specific role in the immune responses. Antibody functions include recognizing and binding to specific antigens, marking them for destruction or neutralization by the immune system. In this article, we will study antibody structure, function, types, and differences between antibodies and antigens.
Table of Content
- What are Antibodies?
- Structure of the Antibody
- Antibody Diagram
- Antibody Types
- Antibodies Functions
- Production and Mechanism of Action
- Applications of Antibodies in Medicines
- Difference between Antigen and Antibody