Learn: Antibodies and Antigens (Specificity)

Welcome!You've already learned about how our body defends itself using white blood cells and barriers like skin and mucus. Now, let's explore antibodies and antigens and how they work together in the immune system.

What are Antigens?Antigens are molecules found on the surface of pathogens (like bacteria and viruses). They are unique to each pathogen and help the immune system identify what doesn't belong in the body.

What are Antibodies?Antibodies are special proteins made by white blood cells called lymphocytes. They attach to specific antigens to help destroy or neutralise the pathogen. Each antibody is unique and fits one specific antigen, like a lock and key.

How Antibodies and Antigens InteractWhen a pathogen enters the body, its antigens are recognised as foreign. Lymphocytes produce antibodies that are specific to the shape of the pathogen's antigens. This is called the specificity of antibodies.

Why Specificity MattersEach type of antibody is highly specific to one type of antigen. This means that if a new pathogen enters the body, the immune system must create new antibodies for it. This is why it can take time to recover from an infection.

How Does This Fight Pathogens?When antibodies attach to antigens, they can directly destroy the pathogen or mark it for destruction by other parts of the immune system. For example, they might clump pathogens together so white blood cells can engulf them more easily.

Vaccines and AntibodiesVaccines work by introducing a harmless version of a pathogen into the body. This triggers the immune system to produce antibodies specific to that pathogen, so the body is prepared if it encounters the real pathogen later.

Review Time!Great work! You've learned about antigens, antibodies, and how specificity helps the immune system. Let’s review with some questions.