Innate Immunity Flashcards
What is the innate immune system?
It is the non-adaptive immune system to defend the host against pathogens. It exists in the germ line and does not undergo any genetic rearrangements.
What are the main cells of the innate immune system?
Phagocytes
What are the two major types of phagocytes found in the innate immune system?
Macrophages
Neutrophils
What are some of the characteristics of macrophages?
- are long-lived leukocytes.
- are widely distributed in normal tissues.
- are often the first cell to encounter a pathogen.
- represent the mature form of circulating monocytes.
- increase in number at sites of injury or infection.
What are some of the characteristics of neutrophils?
- are short-lived circulating leukocytes.
- are the most abundant type of white cell in the circulation.
- are rarely found in normal tissues.
- can be quickly recruited to sites of injury or infection.
What does it mean if neutrophils are seen in high amounts in tissues?
There is likely some sort of problem present in the tissue
What is opsonization?
Opsonization is the coating of particles by molecules that enhance recognition by phagocytes.
Adaptive immunity can opsonize pathogens with antibodies. The innate immune system can opsonize pathogens with proteins of the complement system.
What is the function of cytokines and what innate cells produce them?
Macrophages make them to act on cells to program them for microbial combat
What is the function of chemokines and what innate cells produce them?
Macrophages make them with chemoattractant properties to recruit leukocytes to sites of infection
What is the function of lipid mediators?
They have a similar function to cytokines in reprogramming cells
What are cell surface PRRs?
PAMP recognition receptors
Where are PRRs highly expressed?
Macrophages and dendritic cells
What is the function of TOLL like receptors?
Transmembrane and sense extracellular
infection like bacteria
What is the function of C-type lectin receptors?
Transmembrane and sense sugars for fungal infections
What is the function of Rig-I like receptors?
Cytosolic and recognize viral RNA