Innate Immunity Overview and Mechanisms

Study Notes

Innate immunity serves as the body’s first line of defense against pathogens, offering rapid and non-specific protection.
This defense mechanism does not require previous exposure to pathogens to function effectively.

Physical Barriers: Skin and mucous membranes act as barriers preventing pathogen entry.
Cellular Defenses:
- Macrophages, neutrophils, and dendritic cells play key roles in engulfing and destroying pathogens.
Pattern Recognition Receptors (PRRs):
- Identify and respond to pathogen-associated molecules.
- Types include:
  - Toll-like Receptors (TLRs): Recognize specific microbial components.
  - NOD-like Receptors (NLRs): Detect intracellular pathogens.
  - C-type Lectin Receptors (CLRs): Bind carbohydrates on pathogens.

Inflammation: Initiated in response to injury or infection, increasing blood flow and immune cell recruitment.
Phagocytosis:
- Process where immune cells ingest and eliminate microbes.
- Essential for clearing pathogens and debris.
Complement System:
- A group of proteins that enhance the ability of antibodies and phagocytic cells to clear microbes.
- Promotes inflammation and helps lyse pathogens.

Anti-microbial Proteins: Present at epithelial surfaces and in blood, these proteins provide a direct defense against pathogens.
Infected Cell Recognition: Immune cells can identify infected cells and induce apoptosis to eliminate threats.
Inflammatory Proteins: Enhance the inflammatory response, aiding in recruitment and activation of immune cells.