Topic 3.3
How does specific immunity protect the body from future infections?
Specific immunity is the body’s advanced protection system that fights infections, learns from previous infections, and remembers them for the future. Unlike non-specific immunity, it learns from previous infections and remembers them for the future. This targeted response is precise and adaptable, becoming stronger each time it encounters a familiar pathogen.
Specific Immunity
Specific immunity is sometimes referred to as adaptive immunity. It is slower to respond but can learn from diseases and form a memory. It identifies pathogens by their unique markers (called antigens) and develops a targeted response to eliminate them. Once it has seen a disease and formed a memory, its response is rapid and effective.
This system depends on lymphocytes, a type of white blood cell. There are two types of lymphocytes:
- B cells, which produce antibodies to attack pathogens.
- T cells, which destroy infected cells and signal other immune cells for help.
Both B and T lymphocyte cells originate or are “born” in the bone marrow. B cells stay in the bone marrow to mature, while T cells leave and travel to the thymus gland, where they mature.
Key points about specific immunity:
- Only vertebrates have specific immunity.
- It remembers pathogens, enabling a faster and stronger response to repeat infections.
B and T Cells
B lymphocytes are like the body’s military intelligence system, seeking out their targets and sending defences to lock onto them. T cells are like the soldiers, destroying the invaders that the intelligence system has identified.
Once Leukocytes mature, they are stored or activated in many locations in the body, including the lymphoid organs, which include the thymus, spleen, and bone marrow. Clumps of lymphoid tissue, known as lymph nodes, also exist throughout the body.
Leukocytes circulate between the organs and nodes through lymphatic and blood vessels. The immune system coordinates this process to monitor the body for germs or substances that might cause problems.
Definitions
Write down and research each of the following terms to understand the key terminology better:
- Immune System
- Immune Response
- Pathogen
- First line of defence/Inflammation response
- Second line of defence/Immune response
- Third line of defence
- Non-specific response
- Specific response
- Antigen
- Macrophages
- B cells
- Antibodies
- Killer T cells
- Helper T cells
- Memory B and T cells