2.2 Flashcards
what kind of immunity is essential for effective host defense at the EARLY STAGE of infection
innate
what kind of immunity is essential for MICROBE CLEARANCE
adaptive
what are the steps of the innate immune response
- recognition of pathogen by host cells (receptors for pathogen constituents)
- recruitment of host cells at site of infection (soluble proteins)
- activation of destructive effector mechanisms (effector cells engulf pathogen & kill pathogen or pathogen-infected cells)
what cells are used as a defense mechanism to extracellular microbes & why
- complement macrophages, neutrophils, antimicrobial peptides
- bc accessible to soluble molecules & phagocytes
what cells are used as a defense mechanism to intracellular microbes & why
- NK cells & activated macrophages
- require killing or activation of infected cells
what kind of immunity recognizes structures shared by various classes of microbes that are not present on normal host cells
innate
in innate immunity pattern recognition receptors (PRR) encoded in germ line possess __ & are distributed ___
- limited diversity
- nonclonally
how do cells of the innate immunity identify microorganisms
pattern recognition receptors (PRR) recognize pathogen associated molecular patterns (PAMPs)
what are pathogen associated molecular patterns (PAMPs)
molecules expressed and / or produced solely by microbes
PRR expression and ligands are __
redundant
PRR are localized at ___ & ___ membrane and in the __
- plasma
- endosomal
- cytosol
what do PRR recognize
similar types of ligands
what is TLR signal transduction
the recruitment of adaptor proteins (MyD88 & TRIF) leading to activation of transcription factors and cytokine production
what does TLR3 recruit & what does it trigger
- TRIF
- IFN alpha / beta production
production of type 1 interferon (IFN alpha, beta) leads to an ___
antiviral state
increased expression of cytokines, adhesion molecules, and co-stimulators causes
- acute inflammation
- stimulation of adaptive immunity
what complex is involved in chronic disease development and the activation of inflammatory process that provide the host defenses
inflammasome multiprotein complex
what is NLRP3 inflammasome assembly initiated by
- microbial products
- substances indicating cell damage and death
- endogenous substances in excess in tissues
- inorganic particles
what does NLRP3 inflammasome assembly lead to
caspase-1 activation & results in cleavage of pro-IL1 beta and secretion of IL-1 beta
what does IL-1 beta induce
- upregulation of endothelial cell adhesion molecules
- upregulation of chemokines
NLRP3 inflammasome activation causes accumulation of ___ & ___ at the site of infection
- neutrophils
- monocytes