immune ch 3 (i'm cooked)

PRRs

Pattern-recognition receptors; recognizes common structural compounds of many different pathogen

PAMPs

Pathogen-associated molecular pattern; any structure on a microbe recognized by PRRs

DAMPs

Damage associated molecular pattern; receptors that detect changes to cells/tissues

Scavenger receptors function

subset of PRRs that identify and bind microbial parts and eliminates them + removes cells that died via apoptosis. triggers phagocytosis, cell adhesion and intracellular signaling

TLRs function + use

signal receptors that recognizes variety of microbial ligands; most important is TLR4 that recognizes lipid A of LPS

TLR structure

pattern recognition domain with repeated motif 20-29 amino acids with leucine-rich repeat regions; variations in LRRs + amino sequence = different ligand specificity 

TLR 4 complex

ngl memorize slides 11-12

Extracellular TLR recognition

carbs, lipids, and protein structures on surface of pathogens

intracellular TLR recognition

disdinguish nucleic acids of pathogens vs human cells

Type I interferon function

induce resistance to viral replication, increase of ligands for receptors on NK cells, activate NK cells to kill infected cells

type I interferon pathway

infected cell secretes IFN-B → IFN-B bound to type I interferon receptors which stimulate IFN-a production → IFN-B binds to uninfected cell which produces even more IFN-B

macrophages + neutrophils lifespan and amount

macrophages are long-lived and tissue residing; neutrophils are life span 2 days, circulate in blood waiting for signals. N are most abundant wbc in peripheral circulation (50 bil) 

CXCL8 function

cytokine that recruits peripheral neutrophils to infection site

four steps of neutrophils traveling to infected tissue

rolling adhesion, tight binding, diapedesis, migration

Macrophage and neutrophil pathogen range

neutrophils > macrophages

4 types of granules in neutrophils 

myeloperoxidase, defensin, lactoferrin, gelatinase

Neutrophil phagocytosis progress

once bacteria engulfed endosome fuses with azurophilic, specific and gelatinase (tertiary?) → pH rises due to NADPH oxidase + superoxide dismutase → lysosomes reduce pH and completely degrade bacteria → neutrophil commits apoptosis

Autocrine secretion

cell releases a chemical messenger that binds to its own surface

paracrine

chemical massagers that act on nearby cells

Immune response time

immediate innate = 0-4 hours, induced innate = 4 hours - 4 days, adaptive = 4+ days

cell that makes 1000x more interferons than other cells

plasmacytoid dendritic cells, <1% of total leukocytes, in peripheral circulation

TNF-a and CXCL8 function

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NK cells and viral infections

innate response to viruses/cancer while T cells are developing; levels of IFN-a+b and IL-12 peak

NK cell subpopulations

CD56 (glycoprotein) bright more abundant in tissues, dim in blood; >100 million in circulation. majority of NK cells in uterine are bright, fluxes during menstrual cycle

NK cell activation

infected cells release type I interferon → causes proliferation of NK cells → differentiation of NK cells to cytotoxic effector cells → kills virus-infected cell via inducing apoptosis

NK + macrophage interactions

Macrophages activated by viral infection secrete cytokines which recruit NK → they conjugate, IL-15 + 12 activates NK → NK proliferate + differentiate and secrete IFN-y → binds to macro receptor which increases phagocytosis + cytokine secretion

plasma proteins function

Pathogen recognition + elimination, inflammatory response, and coagulation

most abundant plasma proteins during acute-phase

c-reactive and serum amyloid A (so predictable it’s diagnostic marker for infection + inflammation, tissue damage)

C-reactive protein

opsonin (binds to foreign things making them easier to phag) which triggers classical complement pathway

MBL

calcium dependent lectin (c-ype) ac phase protein; binds to mannose-containing carbs of bacteria, fungi, protozoans and viruses.

Lectin, classical and alt pathway

sldies 46-49 broski

produces plasma proteins

liver stimulated by cytokines released by macrophages