Antibody vs. Antigen
Antibodies and antigens are essential components of the immune system, playing crucial roles in defending the body against pathogens. Understanding the difference between the two is key to understanding how the immune system works.

Antigen
An antigen is a foreign substance that triggers the immune response in the body. These substances can be molecules such as proteins, carbohydrates, or lipids, which are recognized by the immune system as non-self. Antigens can come from pathogens like bacteria, viruses, or fungi, as well as from non-infectious sources like pollen, dust, or certain foods.
- Antigens are recognized by the immune system as foreign invaders.
- They trigger the production of antibodies by the immune system.
- Antigens can be specific to particular pathogens or more general in nature.

Antibody
Antibodies, also known as immunoglobulins, are proteins produced by the immune system in response to the presence of antigens. These Y-shaped molecules bind to specific antigens, marking them for destruction by other immune cells. Each antibody is specific to a particular antigen, creating a highly targeted immune response.
- Antibodies are produced by B cells in response to antigens.
- They help neutralize and eliminate antigens from the body.
- Antibodies play a crucial role in the adaptive immune response.

Key Differences
- Antigens are foreign substances that trigger the immune response, while antibodies are proteins produced in response to antigens.
- Antigens are recognized as non-self by the immune system, while antibodies are specific to particular antigens.
- Antigens can come from pathogens or non-infectious sources, while antibodies are produced in response to specific antigens to help eliminate them from the body.
Understanding the roles of antigens and antibodies is essential for understanding how the immune system recognizes and responds to foreign invaders, ultimately protecting the body from infections and diseases.