Pharmacology - Innate Immunity
What are the cellular events that take place when the innate immune system responds to a cut on your foot?
1. inflammtory factors are produced by tissue resident effector cells 2. local vasodilaiton & increased vascular permeability and leakage 3. recruitment of phagocytes and other inflammatory cells 4. killing of injured or infected cells or damaged tissue cells
What does phagocyte and phagocytosis mean and what type of cells are capable of performing this task?
A phagocyte is a cell that "eats" pathogens Phagocytosis is the process of "eating" the pathogen Neutrophils and Macrophages/monocytes are capable of doing this.
What is the complement system?
A system composed of ~30 soluble plasma proteins that work together to promote pathogen killing
Describe how chemical barriers work.
Chemical barriers work by creating a non-hospitable environment for bacteria and clearing them out, such as lysozymes or proteases
Besides fever, what are the additional systemic effects of these 3 inflammatory cytokines?
IL-6 - induces acute-phase protein production by hepatocytes TNF-alpha - mobilizes the metabolites of shock IL-1beta - produces IL-6
Which 3 inflammatory cytokines play a major role in the process of a fever? How?
IL-6, TNF-alpha, and IL-1beta They activate vascular endothelium and allow for local tissue destruction and an increase in the number of effector cells and production of proteins.
What is special about innate immunity?
Innate immunity is always present but doesn't generate memory
What are the major differences between innate and adaptive immune responses?
Innate immunity is always present, it is quick to activate but has a short duration. Adaptive immunity creates memory cells, it is slow to activate but lasts longer.
What are the major types of cytokines and their functions?
Interleukins - inflammatory respnses Interferon - Type I: induce production of antiviral proteins and activate NK cells. Type II: increase microbicidal activity of macrophages TNF-alpha - induces fever and increases synthesis of inflammatory proteins Chemokines - direct trafficking of leukocytes to sites of inflammation
How does the commensal flora within GI tracts function to compete with harmful pathogens?
It changes the environmental conditions, like pH to make the area less hospitable for harmful pathogens.
Which type of cells produces the cytokines involved in fevers?
Macrophages
What is the function of each type of granulocyte and what is the concept of degranulation
Neutrophil - Phagocytosis Monocyte/macrophage - phagocytosis (more efficient than neutrophils) Basophil and eosinophil - regulate vascular mediators, defend against parasites, secrete toxic substances Degranulation is the rapid release of granules rich in histamine, heparin and chemokines
What are the 2 major types of phagocytes and how does phagocytic killing work?
Neutrophils and Macrophages Phagocytes engulf foreign substances and remove them from the body.
Describe how physical barriers work.
Physical barriers work to prevent bacteria from physically entering the body such as the skin preventing dirt from getting into the blood.
What are the classic signs of inflammation?
Redness, fever and swelling, pain and tenderness
How does a fever develop?
The cells in the area are vasodilated, and inflammatory cells rush in causing a spike in temperature.
What are the major functions of the complement system in immune defenses?
The complement system triggers the release of histamin and other vasoactive substances to increase capillary permeability. It promots inflammation and pathogen destruction
How do inflammatory mediators and major cytokines contribute to the inflammatory process?
They cause local vasodilation, increase vascular permeability and leakage, recruit phagocytes/inflammatory cells and kill injured or infected cells.
What are the functions of natural killer cells?
They destroy compromised host cells by recognizing a condition called "missing self" where MHC molecules are at low levels or altered.
