Lecture 3.1: Detection of Pathogens Flashcards
What are the 2 subsets of the immune system?
Specific
Non-Specific
What are the 3 Stages of Innate Immune System?
- Recognition of microbes and damaged cells
- Activation of mechanisms
- Elimination of the unwanted substances
Stages of Innate Immune System: Recognition
Uses pattern recognition receptors (PRRs) to recognise pathogen-associated molecular patterns (PAMPs) and responds rapidly to invading pathogens
Activates other parts of the immune system and tissues throughout the body
Stages of Innate Immune System:
What are PAMPs?
- Pathogen-associated molecular pattern
* Molecular structures of microbial pathogen that required for survival
What are DAMPs?
- Damage-associated molecular pattern
* Result of cell damage by infections
What are PRRs?
- Pattern Recognition Receptors
* They are cellular receptors
Examples of PRRs?
- Toll like receptor
- RIG-I-like receptors,
- Nod-like receptors,
- C-type lectin receptors.
- Cytosolic DNA Sensor
What are TLRs (Toll Like Receptors)?
- Play a crucial role in the initiation of innate immune response
- Type I transmembrane receptors
What are NOD-like Receptors (NLRs)?
- (NLRs) are a large family
- Cytosolic receptors that sense DAMPs and PAMPs in the cytoplasm.
- Nucleotide Oligomerisation Domain
What are 4 categories of NLR activities?
- Autophagy
- Signal Transduction
- Transcription Activation
- Inflammasome Formation
What NOD-like receptors recognise bacterial peptidoglycan?
- NOD1
* NOD2
Inflammasomes
- NOD-like receptors form multiprotein complexes- the inflammasome
- High molecular weight complex that activates inflammatory caspases
- Activates cytokines of the IL-1 family
Clinical Relevance Inflammasomes
- Gout -metabolic disease
- Severe attacks of pain, redness, and tenderness
- Deposition of monosodium urate, a crystallised form of uric acid
- Uric acid activates the NLRP3 inflammasome
- This induces the formation of IL-1
- Leading to the development of gouty arthropathy
- IL-1-blocking therapy
Cardinal Signs: The 4 -or’s of inflammation
Calor (Heat)
Dolor (Pain)
Rubor (Redness)
Tumour (Swelling)
When does Inflammation occur?
• Fundamentally protective.
• Triggered when pro-inflammatory mediators are released from preformed
stores or quickly produced in response to aN infectious or traumatic event
What is the purpose of Inflammation?
- Intended to destroy or ward off the offending agent
- Interwoven with tissue repair
- Inflammatory process resolves & tissue regeneration/ scar formation occurs
What are the 3 major components of Acute Inflammation?
(1) Dilation of small vessels leading to an increase in blood flow
(2) Increased permeability of the microvasculature enabling plasma proteins
and leukocytes to leave the circulation
(3) Emigration of the leukocytes from the microcirculation, their accumulation
in the focus of injury, and their activation to eliminate the offending agent
Anti Viral State
• Following viral infection IFN-alpha or IFN-beta signalling leads to increased
transcription of various genes coding for host defence proteins
• Results in an antiviral state
What is the Complement System? (3)
Part of the immune system that enhances the ability of antibodies and phagocytic cells to:
- Clear microbes and damaged cells from an organism
- Promote inflammation
- Attack the pathogen’s cell membrane
What is the Definition of Disease?
- A condition that disturbs the normal functioning of your body
- Body can no longer maintain homeostasis
What is the Definition of Illness?
A deterioration of the state of normal health
What is the Definition of Infection?
The invasion and growth of germs in the body outside of normal flora
Sign vs Symptom
Sign is a phenomenon detected by person other than the patient
Symptom is a phenomenon detected by the affected person
