Immunity is the set of mechanisms and physiological responses of the body that enable it to recognise and defend itself against pathogens, such as bacteria, viruses, fungi and parasites, as well as foreign and harmful substances. This immune response involves a highly coordinated network of immune system cells, antibodies and proteins1.
Innate immunity is the body’s first line of defence and is present from birth. It includes physical barriers such as the skin and mucous membranes, as well as specialised cells such as macrophages, Natural Killer cells, or neutrophils, which act rapidly to eliminate invading pathogens.
Adaptive immunity develops throughout life and is highly specific for particular pathogens. It is subdivided into two main categories:
- Humoral immunity: involves the production of antibodies by B cells (B lymphocytes) that circulate in the blood and body fluids, and are essential for neutralising pathogens and toxins.
- Cell-mediated immunity: involves the action of T cells (T lymphocytes) that detect and destroy cells infected by intracellular pathogens, such as viruses and some bacteria.
On the other hand, active immunity is when the immune system produces antibodies in response to exposure to a pathogen or after receiving a vaccine. It provides long-lasting immunological memory.
Passive immunity, on the other hand, is obtained by transferring pre-formed antibodies, usually from an external source, such as the mother through breast milk or through monoclonal antibody treatments.
These different types of immunity work together to provide an effective defence against a variety of infectious threats and foreign substances, thus helping to maintain the health and well-being of the body.
Bibliography:
https://oncouasd.files.wordpress.com/2015/06/inmunologia.pdf
