Innate immunity Flashcards
Is the innate immunity specific/nonspecific?
nonspecific
What are the 3 components of the innate immunity?
- Anatomical barrier
- cellular component
- Humoral component
What factors falls under anatomical barrier?
Mechanical, chemical + biological
What cell is in the anatomical barrier?
epithelial cell
What line of defense is the epithelial cell?
first line
What does the epithelial cells have of content that makes it useful in the innate immune system?
Antimicrobial proteins:
Alpha + beta defensins
Histatins
Surfactant protein A + D
What does epithelial cell secrete and why?
MUCUS –> prevent adhesion
What disease/ condition does NOT have mucus?
cystic fibrosis
What is the mechanical factors in the anatomical barrier?
Skin: keratinized, desquamatation + tight junction
Other: flushing action + mucus
What are the chemical factors in the anatomical barrier?
Fatty acid, sweat, < pH, enzymes + surfactant (opsonins)
What secretes low pH?
Skin + Stomach + Vaginal secretions (post-pubertal)
What enzymes are found in chemical factors?
lysozymes + phospholipase
What are biological factors?
Microbial antagonism + antimicrobial peptide
How does the normal microbiota play a role in biological factors?
- prevent attachment
- compete for growth
- make bacteriocins
- maintain acid pH
Which antimicrobial peptide play a role in biological factors?
Phospholipase + a & b defensin + ribonuclease
What secretes antimicrobial peptide in biological factors?
skin, mucus membranes + intestinal Paneth cells
What is the function of antimicrobial peptide in biological factors?
increased production induced in response to bacterial infection & pro-inflammatory cytokines
which 2 oxygen methods do neutrophils kill in?
oxygen dependent + oxygen independent
Explain oxygen dependent killing in neutrophils.
Phagocyte bind –> phagolysosome
way 1 –> H2O2 –> OH (RADICAL)
way 2 –> MPO + CL –> makes hypochlorite
List enzymes in oxygen independent killing in neutrophils.
protease, phospholipase, nuclease, lysozymes, lactoferrin, glycosylase + basic protein + cationic (cathepsin)
What are NK cells , do they require antigen and how do we find them (which CD)?
They are Large granular non-T, non-B lymphocytes
They dont require antigen
CD56+ CD16+ CD3
What is the role of NK cell?
Important in immune response against virally infected cells & spontaneously arising tumors
How does NK cell do its role?
Activate when T cell activate then apoptosis (by granules containing perforin + granzymes)
How does NK cell work against virus?
Cell has MHC 1 --> virus bind and enter Cell makes micA + micB --> NK bind with KAR + KIR KAR *--> kill KIR *--> doesnt kill * one is usually more than the other
What is cytokine?
small secreted proteins released by cells which may have anti or pro-inflammatory properties
What ways can cytokine act?
paracrine or autocrine way
What is a chemokine?
cytokine with chemotactic property
Why is coagulation system activated?
- Tissue damage
- Vasodilation
- phagocyte chemotactic
- antimicrobial activity
What is complement system? And how many pathways are there and name and describe them.
Helps clear pathogen by aiding phagocytosis
o Classical: has immune complex (antibody + antigen bound together)
o Lectin pathway: manose binding lectin complex
o Alternative pathway: pathogen coated by c3b
Explain the classical pathway + its activation
Antigen + antibody –> C1 –> Antigen + antibody + C1 + C4B –> Antigen + antibody + C1 + C4B + C2A –> c3 covertase
To activate: c3b + c5a
Explain the lectin pathway + its activation
Antigen + MBL –> Antigen + MBL + C4B –> Antigen + MBL + C1 + C4B + C2A –> c3 covertase
To activate: c3b + c5a
Explain the alternative pathway + its activation
pathogen + C3B + FACTOR B –> (factor D makes factor Bb) –>pathogen + C3B + FACTOR Bb –> c3 covertase
activation:c3 covertase + factor p + c3b –> c5 convertase + c5a + c3b
What makes pores in MAC?
C9
What is the c1 inhibitor?
serpin
What is the c3 inhibitor?
DAF
How to stop mac?
C59
What complements activates basophil?
C3a + C4a + C5a
What is opsonization?
Coating microbe with complement proteins
What is the pathway to phagocytosis?
Opsonization and phagocytosis –> Inflammation –> Lysis
How does the innate system recognize pathogens?
- PRR bind to PAMP
- DAMP (tissue damage)
- NK
What are PAMP + PRR?
PAMP on bacteria –> needed for survival (e.g LPS + petidoglycan + DNA etc)
PRR: toll like receptor that bind to PAMP –> initiate phagocytosis + cytokine + etc
Are PRR in serum?
some can be! C-reactive protein (CRP) + serum amyloid
How to activate complement?
- Pathogen enter body
- Chemotactic factors made by receptors (PRR)
- PRR bind to PAMP on bacteria –> recognized by toll like receptor
- Macrophage is activated –> phagocytosis
- Cytokines (pro-inflammatory made) + chemokine
- IL8 attract neutrophil
- Neutrophils come –> transmigration –> inflammation
What is an example of DAMP?
phosphatidylserine
