Antigens as Recognition Molecules That Trigger Antibody Production
- Imagine your body as a well-guarded fortress.
- To keep invaders out, it relies on a sophisticated system of recognition and defense.
- At the heart of this system are antigens are molecules that act as "name tags" for foreign invaders, alerting your immune system to take action.
Definition
Antigen
Foreign molecules, usually proteins or glycoproteins, that trigger an immune response by being recognized by the immune system.
What Are Antigens?
- Structure: Most antigens are glycoproteins (proteins with attached sugar molecules) or other proteins.
- Location: They are typically found on the outer surfaces of pathogens, such as bacteria, viruses, and fungi.
Antigens can also be found on non-pathogenic cells, such as transplanted organs or mismatched blood cells, which can trigger an immune response.
How Do Antigens Trigger Antibody Production?
- Recognition of Non-Self: The immune system uses antigens to distinguish between self (your body’s cells) and non-self (foreign invaders).
- Activation of Lymphocytes:
- Helper T-Cells: Recognize antigens presented by macrophages and activate B-cells.
- B-Cells: Produce antibodies specific to the antigen.
Step-by-Step Process of Antibody Production
Antigen Recognition
- Antigens on the surface of a pathogen are recognized by specific B-lymphocytes.
- Each B cell has receptors on its surface that can bind to a specific antigen, which acts like a key fitting into a lock.
Activation of B-Lymphocytes:
- The binding of the antigen to the receptor on a B cell triggers the activation of that B cell.
- The activated B cell then undergoes clonal selection, where it divides rapidly to produce a clone of identical B cells.
Definition
B lymphocytes (B cells)
White blood cells that recognize specific antigens and produce antibodies to neutralize pathogens.
