Immunity is primarily caused by the body's exposure to antigens, which triggers the development of acquired immunity, as well as by receiving antibodies through passive immunity.
Understanding Immunity
Immunity is the body's ability to defend itself against harmful substances like bacteria, viruses, and toxins. It's not a single, simple process but a complex interaction of different systems. There are two main types of immunity: acquired and passive.
Acquired Immunity:
- Development: This type of immunity is developed by exposure to various antigens. An antigen is a substance that causes an immune response.
- How it Works: When your immune system encounters an antigen, it builds defenses specifically targeted to that antigen. This allows the body to recognize and neutralize it on future encounters.
- Examples:
- Infection: Getting sick with a disease can result in acquired immunity. For example, after having chickenpox, you are typically immune to it for life.
- Vaccines: Vaccines introduce harmless versions or parts of antigens, like a virus, to your body. This triggers your immune system to create antibodies without causing the actual disease. As explained in the reference, "Vaccines work by causing acquired immunity without needing to have the infection first."
- Long-Lasting: Acquired immunity is generally long-lasting.
Passive Immunity:
- Development: Passive immunity is temporary immunity due to antibodies that are produced in another body and then transferred to your own.
- How it Works: You are not creating the antibodies yourself; rather, you are receiving them from an outside source.
- Examples:
- Maternal Antibodies: A newborn receives antibodies through the placenta during pregnancy and through breast milk. This gives the baby initial protection against common infections.
- Blood products (like plasma): Antibodies can be given directly to a person who needs an immediate immune boost, such as after a disease exposure.
- Short-Term: Passive immunity is short-lived as the antibodies are not being made by the recipient's immune system.
Summary of Immunity Causes
| Type of Immunity | Cause | Duration | How it Works |
|---|---|---|---|
| Acquired Immunity | Exposure to antigens (through infection or vaccination) | Long-Lasting | The body builds its own specific defense against a given antigen. |
| Passive Immunity | Receiving antibodies from another source | Short-Term | The body receives pre-made antibodies, without producing them itself. |
In conclusion, immunity is either developed through direct exposure to antigens, thereby enabling an individual to mount a defense, or through the receipt of antibodies. The reference highlighted that acquired immunity is the result of exposure to various antigens.
