12a Host defense Flashcards
Lysozyme
AMP- hydrolase very good at breaking down cell walls
Bacteriosins
Bascally defensins created by good bacteria
Lactoferrin
Glycoprotein
- sequesters iron
- oxidizes cell walls
Tamm-Horsfall protein
Inhibits uropathogenic E.coli from binding urinary epithelium
Epithelial ion transport in the gut
- CFTR expels CL- in response to cAMP/PKA signaling downstream of VIP
- Driven by 2Cl/K/Na transporter on basolateral side of cell
- K/Na Atpase pushes sodium back out of the cell
TGF-Beta
Inhibits lymphocytes and promotes epithelial division, differrentiation and migration
Promotes IgA differentiation of plasma cells
TLR distribution in the gut
Basolateral epithelial surface
Dendritic cell surface
ALSO NLR- cytoplasmic TLR in epithelials activated with intra-cytoplasmic peptidoglycan
Mannose receptor
Membrane receptor on phagocytes- recognizes bacterial cell wall carbohydrates and fungal wall peptidoglycans
CRP
Soluble PRR that recognizes microbial cell wall components
Downstream bacterial TLR genes
TNF, IL1, IL6
Downstream TLR genes - viral pathogens
IFN alpha and beta
Minimally invasive intestinal pathogens
Campylobacter
Clostridium
Candida
Cryptococcus
Invasive intestinal pathogens
Listeria
Enteroinvasive E.Coli
opportunist: Clostridia/ Shigella
Toxogenic gut bacteria
Enterotoxoggenic E.Coli
Vibrio Cholerae
(Clostridium and shigella)
TLRs
TLR 2- Bacteria only
TLR 3– Fungi and viruses
TLR 4,5 - bacteria and fungi
TLR 7, 9 - viruses
Epithelial activation
Occurs via
- IL1 and TNF from APCs and PMNS
- IL22 and IL17 from Th17 later on
IL12
Dendritic cell product that activates macrophages
Mucosal
IgG/A pathway
Epithelials–> IL6, IL23, TGF-B—> Push TH17 and B->Ig secreting cells
APCs–> IL12–> Th cells –>Th1–>IFNg–>IgG plasma cells
IFN alpha and Beta
Produced in epithelial cells in response to viral invasion via TLR/NLR
Granulocyte activation in parasitic infection
Causes release of:
- Vasoactive amines (promotes smooth muscle action)
- Proteinases
- prostaglandins and leukotrienes
- Cytokines
Th17 cells
Extracellular bacterial and fungi
*stimulated by TGFb, IL6, IL23
Release IL17, IL22- activate epithelials Attract neutrophils and monoctes