What is inborn immunity?

Inborn immunity (or innate immunity) is the body's first line of defense against infection and disease. It is present from birth and provides a rapid, non-specific response to pathogens and other harmful substances. Inborn immunity includes physical, chemical, and cellular barriers that work together to protect the body.

Components of Inborn Immunity:

1. Physical Barriers:

- Skin: The skin acts as a physical barrier that prevents pathogens from entering the body.

- Mucous Membranes: The mucous membranes line the respiratory, digestive, and urogenital tracts and secrete mucus that traps and removes pathogens.

- Saliva, Stomach Acid, and Tears: These fluids contain antimicrobial substances that can kill or inhibit the growth of pathogens.

2. Chemical Barriers:

- Antimicrobial Substances: Certain cells, such as neutrophils and macrophages, produce reactive oxygen species (ROS), nitric oxide (NO), and antimicrobial peptides that can directly kill pathogens.

3. Cellular Barriers:

- Phagocytes: These cells, which include neutrophils, macrophages, and dendritic cells, engulf and destroy foreign particles, including pathogens.

- Natural Killer (NK) Cells: NK cells recognize and kill virus-infected or abnormal cells.

- Cytokines: These small proteins are released by immune cells and act as chemical signals that coordinate the immune response.

Activation of Inborn Immunity:

Inborn immunity is activated when pattern recognition receptors (PRRs) on immune cells recognize pathogen-associated molecular patterns (PAMPs) on the surface of pathogens. This recognition triggers a series of signaling cascades that lead to the activation of immune cells and the production of inflammatory mediators.

The inflammatory response is a key feature of inborn immunity. It involves the release of cytokines and other inflammatory mediators that cause increased blood flow, vascular permeability, and the recruitment of immune cells to the site of infection. This response helps to limit the spread of pathogens, promote tissue repair, and facilitate the adaptive immune response.

In summary, inborn immunity is a vital part of the body's defense against infection. It provides a rapid, non-specific response to pathogens and helps to limit the spread of infection and promote healing.