Intro - Innate Immunity Flashcards
What is the central problem that the Immune System must deal with?
Invasion by microbial pathogens
What is the main task of the Immune System?
To distinguish self from non-self
Must not attack or destroy self;
Must eliminate whole organisms (bacteria, fungi)
Must eliminate intracellular pathogens (viruses, cancers)
What is Innate Immunity?
What are some physical examples?
Also called “Natural” immunity; evolutionarily old.
Ex: Skin, mucous membranes
What are some examples of Innate Immunity?
Anatomic barriers: skin & mucous membranes
Physiologic barriers: temperature, pH, oxygen tension, soluble factors (lysosyme, interferons, complement)
Endocytosis/Phagocytosis
Inflammatory Response: Vasodilation, influx of phagocytic cells (margination, extravasation, chemotaxis)
Soluble mediators involved in inflammation: acute phase proteins, histamines, kinines
What are the Anatomic Barriers of innate immunity?
- Skin: epidermis has keratin, low pH, prevents bacterial growth
- Mucous membranes: traps organisms (cilia moves those trapped organisms)
What are the Physiologic Barriers of innate immunity?
- Temperature: prevent bacterial growth
- pH
- oxygen tension
- soluble factors
What are the Soluble Factors of the physiologic bariers of innate immunity?
- Lysosyme: Found in mucous, cleaves bacterial peptidoglycans (cell wall).
- Interferons: produced by infected cells, antiviral effects (shuts cell down).
- Complement: series of proteins, form a cascade on exposure to sialic acid, lead to bacterial lysis.
What are lysosymes?
They are Soluble Factors of the physiologic bariers of innate immunity.
They are found in mucous.
They cleave bacterial peptidoglycans (cell wall).
What are interferons?
They are Soluble Factors of the physiologic bariers of innate immunity.
They are produced by infected cells.
They are antiviral in nature (shuts cell down).
What is complement?
They are Soluble Factors of the physiologic bariers of innate immunity.
They are a series of proteins that form a cascade on exposure to sialic acid and lead to bacterial lysis.
What is endocytosis?
It is part of innate/natural immunity.
It is present in all cells.
It delivers macromolecules to endosomes (a vesicle formed by the invagination and pinching off of the cell membrane during endocytosis).
What is phagocytosis?
It is part of innate/natural immunity.
Not present in all cells, only Monocytes, Macrophages, Neutrophils.
Engulfs particles/organisms via receptors, degrades them in lysosymes (surround with cytoplasm). The receptor for this binds lipopolysaccharides/LPS (unique to bacteria).
What is the inflammatory response?
It is part of innate/natural immunity and involves getting immune cells to the site of infection.
- Vasodilation: Expansion of blood vessels, contraction of blood vessels, expansion, swelling at site
- Increase in capillary permeability. Exudate released (fluid that exudes out of a tissue or capillaries due to injury or inflammation)
- Influx of phagocytic cells: (macrophages, neutrophils) - margination, extravasation, chemotaxis
What is vasodilation?
It is part of the inflammatory response of innate/natural immunity, and involves getting immune cells to the site of infection.
It is the expansion of the blood vessel, which increases capillary permeability and thus allows the influx of phagocytic cells (margination, extravasation, chemotaxis) to the site of infection.
What is margination?
It is part of the inflammatory response of innate/natural immunity.
When there is an influx of phagocytic cells, it refers to the adherence of these cells to the capillary wall.
