Lecture 2 Flashcards
Who is Ilya Mechnikov?
Father of innate immunity
What was Mechnikov’s discovery?
first to demonstrate phagocytosis and usefulness of inflammation
how did Mechnikov demonstrate phagocytosis?
put mango thorn into translucent starfish larvae –> cells gathered around thorn, therefore cells must have purpose
how does Mechnikov’s experiment relate to what we know today?
mimics the neutrophil swarm during infection
what did Janeway theorize?
in order for phagocytes to attack, the innate immune cells must recognize components of microbes –> determine self vs non-self
how do innate immune cells distinguish self vs non-self?
PRRs on innate immune cells recognize microbial component, PAMPs, on microbes
2 examples of PAMPs
- dsRNA
- LPS
What is an immunologist’s “dirty little secret”? how does it work?
adjuvants –> dead mycobacterium and other components that were PAMPs that stimulate immune response
why is there a diverse set of PRRs?
to be able to detect many different microbe PAMPs
why do PRRs follow the idea of “form follows function”
location of receptor determines what PAMP it can detect and therefore downstream effector function
ex. receptors inside the cell bind viral PAMPs
ex. receptors outside the cell bind extracellular pathogen PAMPs
what is a limitation of Janeway’s PAMP hypothesis based on Metchnikov’s observation? significance?
the thorn is not a pathogen but the cells were still able to migrate –> therefore, maybe our immune response senses DAMAGE rather than pathogen/non-self
what is Matzinger’s Danger Theory?
innate immune cells detect danger via indicators of cell stress/dysfunction/death, not just detection of PAMPs
what is the term for things that trigger innate immune cells in the Danger theory?
DAMPs –> microbial and non-microbial inflammatory triggers
2 general types of inflammation inducers
exogenous and endogenous
2 types of exogenous DAMPs
microbial and non-microbial
4 types of endogenous DAMPs
- cell-derived
- tissue-derived
- plasma-derived
- ECM-derived
another name for some endogenous DAMPs?
ALARMINS –> alarm the innate immune cells to activate
4 core components of inflammation
- INDUCERS (stimulants)
- SENSORS (detectors)
- EFFECTORS (cell type)
- MEDIATORS (soluble factors)
what are the sensors in inflammation?
PRRs –> detect pathogens and damage
what are the effectors in inflammation?
basically every cell in our body is an immune cell according to the danger theory because all can detect stress
what are 5 mediators in inflammation?
- cytokines
- chemokines
- anti-microbial peptides
- Ab
- lipid mediators
why do we need mechanisms to control inflammation?
too much inflammation is bad!
what happens if inflammation causes too much tissue repair? (2)
- leads to fibrosis –> compromises elasticity of tissue so it cannot function properly
- excess collagen deposition allows tumour to grow bc immune system cannot interfere with tumour
what happens in chronic inflammation?
system gets so stressed –> leads to tissue malfunction bc body can only handle so much inflammation and stress –> leads to disease