Lecture 2 Flashcards
True or false: Dendritic cells can come from both the common lymphoid progenitor and common myeloid progenitor
True
What are the 4 ways the innate immune system work?
- PREVENTS infection
- RECOGNIZING microbe
- ALARMING other cells/tissues
- DESTROYING the microbe/infected cells
True or false: Physical barriers are not considered part of innate immunity
False
Physical barriers are considered part of innate immunity
What are the 3 ways to prevent microbes from crossing skin/epithelial barrier
- Mechanical
- Chemical
- Microbiological
How does mechanical prevent microbes from entering
- Epithelial cells joined by tight junctions (skin barrier)
- Flow of fluid and mucus
How does chemical prevent microbes from entering
- Acids
- lysozymes
- Acidity
- Low pH
- ANTIMICROBIAL PEPTIDES (DEFENSINS)
How does microbiological prevent microbes from entering
Uses the normal flora
What is complement?
A system of proteins made by the liver that help innate immunity
What is used to recognize pathogens?
Soluble proteins
-Pathways of complement activation
What are the 3 pathways of complement activation
- Alternative Pathway
- Lectin Pathway
- Classical Pathway
Which pathway is the first to act in complement activation?
Alternative
Which is the last pathway to act?
Classical
Why is it the classical pathway the slowest to be activated?
The classical pathway uses antibodies, and antibodies come from adaptive immunity
-Adaptive immunity has a slow response
What is the alternative pathway?
Chemical surface that activates when pathogen reaches surface
What is the Lectin pathway?
Mannose-binding lectin binds to pathogen surface
What is the Classical pathway?
C-reactive protein/antibody binds to specific antigen on pathogen surface
What does each pathway lead to?
Each pathway leads to complement activation (antibody + pathogen) & cleaves C3 into C3a and C3b
-C3b binds to pathogen
What does C3a & C5a path result in?
ALARM
-recruitment of inflammatory cells
What does C3b pathway lead to
DESTROY
-Opsonization of pathogens
What does C5b pathway lead to?
DESTROY
-Perforation of pathogen cell membranes
What happens when C3 gets cleaved?
C3 turns into C3a and C3b
-C3a recruits phagocytes
-C3b binds to bacterium/pathogen
What happens when C3b binds to bacterium/pathogen?
When C3b binds to bacterium/pathogen, C5 cleaves into C5a and C5b
What is opsonization?
Pathogen is marked for phagocytosis
-opsonin enhances this
What can recruit immune cells and how?
C3a and C5a by increasing vascular permeability
What is inflammation characterized by?
- Heat
- Redness
- Swelling
- Pain
Why is there heat and redness in inflamation?
-C3a and C5a increrase vascular permeability which means more blood can flow into the vessels which causes heat & redness
What causes swelling and pain in inflammation?
More plasma proteins enter the cell casuing crowding which leads to pain and swelling
Which cells mediate innate responses?
- Neutrophils–>bomb
- Macrophages–>Collector
- Dendritic cells (most powerful)–>Detective
- Natural killer cells–>Border Patrol
What is LPS recognized by?
TLR4
What does RIG-I recognize?
double stranded RNA
What are the membrane associated receptors?
TLRs
What are the cytosolic receptors?
-Nod-like receptors
-CARD-family receptors
What does cGas recognize?
cytoplasmic DNA
What does IKK protein kinase lead to?
IKK phosphorylates transcription factors that degrade NFkB inhibitor which lets it go into nucleus and make cytokines and chemokines
What does TBK1 protein kinase lead to?
Phosphorylates IRF3 which leads to type 1 interferons: IFN alpha and beta
What is the adaptor, protein kinase, and product of TLR
-Myd88 or TRIF
-IKK protein kinase
-NFkB makes cytokines/chemokines (MyD88)
-TRIF pathway phosphorylates RF3 to make type 1 interferons
What is the adaptor, protein kinase, and product of CARD/RIG-I?
-MAVS/IPS-1
-TBK1
-IRF3
-type 1 interferons
What is the adaptor, protein kinase, and product of cGAS
-STING
-IKK or TBK1
-Chemokines/cytokines or interferons
