Innate Immunity Flashcards
Neutrophils in the Immune System
Primary phagocyte
initiates inflammation after a cut/scrape
Main component of pus-yellow/white
Reactive Oxygen Species (ROS) that kills pathogens
Neutrophil extracellular traps
Basophl and Mast Cells
Basophils: similar to neutrophils, in blood
Mast cells: in tissue
- Histamines, inflammatory mediators, allergic disease
- Regulate some helper T cells, stimulate B cells to produce IgE
Eosinophils
Primary phagocyte against multicellular microbes, parasites
Neutralize basophil and mast cell products
Regulate mast cell function
Monocytes and Macrophages
Non-granulocytic
Become macrophages in the tissue
Eat pathogens
Presents antigens to T cells
Clean up debris from immune response
Not a uniform population
Some are better at recognizing different threats, some are more inflammatory or better at phagocytosis, wound healing, clearing danger signals, etc.
Dendritic Cells
Phagocytose antigen and presents it to helper T
After attaching to antigent, migrate to lymphoid sites to sho T cells
Most potent phagocytic cell in tissue
Lymphocyte Categories
Adaptive: T and B lymphs
Innate: NK cells
Natural Killer NK Cells
Lymphoid cells
Main functions: kill tumor or infected cells, doesn’t need memory
Directly activated by: absense of inhibitory signal, antibody dependent cell-mediated cytotoxicity (ADCC)
Function of Innate Immunity
- Detection of pathogen/danger signals
- Removal of potential pathogens
- Alerting other immune cells of potential threats
- Antigen processing and presentation, mount specific response later
Hallmark Feature of Innate Immunity
Pathogen-associated molecular patterns (PAMPs): ability to ID common molecular patterns found on groups of microbes
Danger-associated Mol Pat (DAMPs): also able to recognize danger signals from our own cells
Pathogen Associated Molecular Patterns
Common molecules in classes of microbes
- unique nucleic acid patterns, lipids, and carbohydrates
- things like dsRNA in viruses, mannose, lipopolysaccaride, lipoproteins
Think cell walls of bacteria, peptidoglycan,
Damage/Danger-Associated Molecular Pattern Molecules (DAMPs)
Produced by damaged cells, initiate a response to trauma, cancer, other settings of tissue damage in absence of overt pathogen infection
Depends on type of cell and injured tissue
Proteins: nuclear proteins, calcium binding proteins, heat-shock proteins
Non-proteins: nucleic acids, purine metabolites (ATP, uric acid)
Pattern Recognition Receptors
Induces inflammatory response
Receptors that recognize PAMPs and DAMPS
Cellular PRRs: found externally or internally of cell, induce signaling within cell for activation, facilitate phagocytosis
Soluble PRRs: bind extracellular microbes, clearance mechanisms, phagocytosis
How Cells Alert Other Cells
- Recognize non self molecules by pattern recognition receptors
- Activates innate immune cells
- Activated cells produce cytokines
- Vasodilation, and leukocytes travel to site of infection
Acute Phase Proteins
- Produced in response to increase in intercellular signaling cytokines
- Normal serum constituents, increase or decrease rapidly due to infection, injury, trauma
- Mostly produced by hepatocytes, can be produced by innate cells
- May bind to microbe, promote cell binding
C-Reactive Protein
Serum protein attached to foregin substance, neutralizes charge to make cells be able to approach each other
- Nonspecific
- Most widely used indicator of acute inflammation because it rises and declines so rapidly
