The fight against illness
- Pathogens produce the symptons of an infectious disease by damaging the body's cells or producing poisonous waste products called toxins.
- The body protects itself by producing antibodies, which lock onto antigens on the surface of pathogens such as bacterium. This kills the pathogen.
- Human white blood cells produce antibodies, resulting in active immunity. This can be a slow process but has a long-lasting effect. Vaccinations using antibodies from other human or animal result in passive immunity, which has a quick but short-term effect.
- Each pathogen has its own antigens, so a specific antibody is needed for each pathogen.
- The process of immunisation is also called vaccination - It starts with injecting a harmless pathogen carrying antigens. The antigens trigger a response by white blood cells producing the correct antibodies. Memory cells (a type of T-lymphocyte cell) remain in the body, providing long lasting immunity to that disease.
- Immunisation carries a small risk to the individual, but it avoids the potentially lethal effect of the pathogen, as well as decreasing the risk of spreading the disease.
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