what are the 3 barriers of the immediate immune system
mechanical
chemical
microbiological
what are the 2 soluble effectors of the immediate immune system?
complement
antimicrobial peptides
innate immunity is a system of what?
pattern recognition
what are the four components of the innate immunity?
barriers
soluble effectors
cells
cytokines
what are 4 pathogen associated molecular patterns (PAMPs)
LPS
flagellin
mannose sugars
unmethylated CpG DNA
what are 3 damage-associated molecular patterns?
heat shock proteins
fibronectin
chromatin
**induces inflammation
what is an example of pattern recognition receptors?
Toll like receptors aka TLRs
what are the mechanical barriers?
epithelial cells joined by tight junctions
flow of fluid on surface
what are the chemical barriers
fatty acids low pH surfacatant enzymes in tears alpha and beta defensins
what are the microbiological barriers?
normal microbiota
mechanical barriers prevent infiltration, how?
- physically block pathogens from entering
- barriers are not passive
- mucosal cells produce chemical barriers
- specialized immune tissues are integrated into barriers(eg: payers patches)
what is the importance of lymphoid tissues that are integrated into barriers?
-where B and T cells are locally activated
example is payers patches in the ilium
-connected to the lymphatic system
-have less structure than lymph nodes
every mucosal tissue has what two things?
- secretion-traps pathogens
- motility-removes pathogens from mucosal surface
what are two ways that chemical barriers get ride of pathogens?
- isolation and physical removal
- targeted destruction(eg: lysozyme that cleaves peptidoglycan)
what are chemical barriers made of and where is one place they can all be found?
peptides and proteins mostly with some lipids and carbohydrates
**all can be found in the mouth
lysozyme
cleaves glycosidic bonds of peptidoglycan allowing the cell membrane to be exposed
lactoferrin
- binds and sequesters iron, limiting growth of bacteria and fungi
- limits infectivity of some viruses
- disrupts microbial membranes
defensins (alpha and beta)
disrupts membranes of bacteria, fungi, protozoan parasites, and viruses.
- also has toxic effects intracellularly
- kill cells and disable viruses
- *puts a hole in the cell membrane
surfactant proteins
block bacterial surface components and promotes phagocytosis
what type of defensin is released by a PNM
alpha
what type of defensin is released by mucosal surfaces in the body?
beta
* constitutively
what do defensins do
make holes in bacteria cell membranes because they are positively charged. remember cell membrane is negatively charged.
do defensins affect eukaryotic cells?
no due to proteins and other lipids in the membrane
what is another function of defensins other than make holes in bacterial cell membranes?
signaling molecules
eg: chemotaxis, opsonization
defensins are prominent in the oral epithelium, where do they come from and where are they found?
- neutrophils secrete alpha into GCF
- startified oral epithelium constitutively release beta defensins
- *can control the type of bacteria present
what type of bacteria form barriers in the gut?
mutualistic-both benefit
commensal-one benefits one doesn’t benefit or get harmed
what are the functions of the microbiota of the gut?
- pathogen displacement
- nutrient competition
- receptor competition
- produce antimicrobials
- induce IgA
- aide in metabolism of food and synthesis of vitamins
how does the mucosal flora interact with the immune system
- antimicrobial peptides shape the flora
- commensal outcompete pathogenic
- pattern recognition receptors(PPR) detect commensal bacteria and prevent inflamm
- commensals induce IgA and antimicrobial peptide release
- dendritic cells constantly browse mucosal flora
T/F resident microbiota are resistant to defensins of the gut?
true
what is the complement system?
plasma proteins that act in cascades to selectively kill extracelluar pathogens and diseased tissue, promote inflamm, clear tissue damage, regulate tissue homeostasis
what are the three complement pathways?
classical
lectin
alternate
what are the three outcomes of the complement?
- phagocytosis (opsinization)
- lysis (MAC)
- activating adaptive immune system
how do barriers actively resolve pathogens?
antimicrobial peptides and removal of pathogens
how do barriers passively resolve pathogens?
prevent entry of pathogens into host
