Innate Immunity Flashcards
Antibiotic therapy can lead to loss of _____, allowing pathogens to grow out
Commensals
What types of pathogens do Toll-Like Receptors help defend against, what cells are they expressed on, and what type of reaction do they induce?
Bacteria, fungi and viruses. On monocytes/macrophages and dendritic cells. Induce inflammation
Which receptors are at the PM and which are in the endosome: TLR-2, TLR-3, TLR-4, TLR-7 and TLR-9?
TLR-2 and 4 are at the PM, TLR-3, 7, and 9 are in the endosome
What is the major component of gram-negative bacteria outer membranes and what human receptor of the innate immune system recognizes it?
Bacterial lipopolysaccharide, recognized by TLR-4
What does TLR-9 recognize?
Unmethylated CpG DNA, a hallmark of bacterial DNA
What are the three main receptors in the innate immune system?
Toll-Like Receptors (TLRs), Mannose receptors and RIG-like Receptors (RLRs)
What do Rig-Like Receptors (RLRs) recognize?
Viral RNA
What two types of molecules do innate immune cells emit and what does each do?
Type I interferons (alpha and beta) - have anti-viral properties, and Pro-inflammatory cytokines and chemokines - attract effector cells
Endothelial cells produce chemokines and adhesion molecules to attract monocytes and neutrophils. What stimulates them to do so?
Cytokines from macrophages
Name four types of phagocytic cells
Circulating monocytes, resident macrophages, dendritic cells, neutrophils
Activation of innate phagocytic cells leads to production of what toxic species?
ROS, NO, and lysosomal proteases
Name 5 cytokines produced by innate phagocytic cells, what cell type produces each, and what each does
Type I interferons - any infected cell, is anti-viral, TNFa - Macrophages and DCs, increases vascular permeability, IL-1 - Macrophages and keratinocytes, induces acute phase proteins, IL-6 - Phagocytes, endothelial cells, fibroblasts, release of acute phase proteins, IL-8 (aka CXCL8) - phagocytes, attracts neutrophils
TNFa and IL-1 induce expression of what proteins in endothelium to attract inflammatory cells?
P-selectin and E-selectin
Binding of what leukocyte protein to what endothelial protein causes extravasation?
Leukocyte LFA-1 binding to endothelial ICAM-1
What leads to pus formation at sites of injury?
Neutrophils ingest pathogens and then die, releasing pus
NKG2D
A receptor in NK cells which recognizes molecules that resemble MHC class I molecules (expressed on stressed or infected cells)
What are two activating receptors for NK cells and what is an inhibiting receptor?
NKG2D and Fc (for IgG or IgE) receptors are activating, MHC class I recognizing receptors are inhibiting
What cytokines activate NK cells?
Type I interferons, IFNg, IL-12
Where do gamma-delta T cells live and what do they do?
In epithelia and in the gut, they recognize self components that are altered by infection
What type of cell recognizes microbial glycolipid antigens and what receptor presents these molecules?
NK T cells (found in epithelia, liver, and lymphoid organs). Presented by CD1
B1 Cells
Found in pleural and peritoneal cavities with specificities for common targets in the gut, often polysaccharides. Produce IgM
What cytokines in particular produce an acute phase response?
IL-1, IL-6, and TNFa
Two important acute phase proteins and what each does
C-reactive protein - binds phosphocholine (on surface of dead or dying cells), and Mannose-binding lectin - recognizes microbial carbohydrates and can coat microbes or activate complement
What are four roles of the acute phase response?
Neutrophil mobilization, increase body temperature, protein and energy mobilization, dendritic cell maturation
