Ch 2 Innate Immunity Flashcards
External defence system
Anatomical barriers,
Psoriasin
small protein, antibacterial effects against gram negative (E. coli)
Mucous membranes
mucus block adherence, respiratory, digestive, genitourinary tract
Surfactants
in mucus, produced by epithelial cells and bind to microorganisms
Lysozymes
enzyme in tears/saliva, attack gram positive cell wall
Internal defence system
includes acute phase reactants, finding and phagocytosis
Acute phase reactants
soluble factors that help contact/adherance/bind between microbes and phagocytes, rapid increase/decrease to infection
Positive acute phase reactants
Hepatocytes (liver parenchymal cells) produce due to cytokine increase (interleukin-1, 6, TNF) from mono/macro
C-reactive protein (CRP)
(calcium dependent) binds to receptors and promotes phagocytosis, similar to antibody (opsonins, agglutination, complement), acute inflammation indicator/vascular disease
Serum amyloid A (SAA)
activate mono/macro to increase inflammation, chemical messenger
Alpha-Antitrypsin (AAT)
major component of A band in electrophoresis, protease inhibitor released from leukocytes, regulates proimflammatory cytokines (interleukins/TNF), inhibits mono/macro activation (damage/emphysema)
Fibrinogen
coagulation (clot) pathway, promote aggregation of RBC/PLT (viscous/heart attack)
Haptoglobin
antioxidant protect by irreversibly bind to free Hb from intravascular hemolysis
Ceruloplasmin
copper transporting protein in plasma, enzyme converts ferrous Fe2+ to ferric Fe3+, (Wilson’s disease - autosomal recessive genetic disorder copper increase)
Complement C3
opsonin, lysis, chemotaxins
Pattern recognition receptors (PRRs)
Neu/eos/mono/mast/epithelial, bind to pathogen, activate phagocytosis
Cytokine/Chemokine
chemical messengers that make capillaries more permeable and recruit more phagocytes/trigger adaptive immune response
Pathogen Associated Molecular Patterns (PAMPs)
how PRRs tell apart self, only found in microbes (lipopolysaccharide/zymosan)
Toll-like receptors (TLR)
monocytes/macrophages/dendritic, bind to substance cytokine/chemokine activate (receptors activate immune responses)
C-type lectin receptors (CLR)
plasma membrane receptors on mono/macro/den/neu/B/T, bind to fungal cell wall
Retinoic acid-inducible gene-I-like receptors
RNA in viruses in cytoplasm of infected cells and induce inflammatory cytokines/type I interferons(inhibit viral replication/apoptosis)
Nucleotide binding oliglomerization domain (NOD)-like receptors (NLR)
immune surveillance in cytoplasm, bind to ligands (pamps)
Inflammasome
NLR, multiprotein unit activate apoptotic proteins and proinflammatory cytokines
Inflammation
body’s overall reaction to antigen (attract cells to site), erythema (redness), edema (swelling)
1. histamine from mast
2. increased capillary permeability fluids to tissue
3. WBC diapedesis, acute phase reactants
4. macrophage migration
5. APR stim phagocytosis
Phagocytosis
- physical contact
- cytoplasm surround
- formation of phagosome
- fusion of lysosomal granules to phagosome
- phagolysosome, lysosomal release contents
- digestion
- debris release exocytosis
Oxidative burst
O2 dependent pathway to eliminate pathogens, HMP converts NADP to NADPH (reduced), O2 to O2- (superoxide) to H2O2 and OH- (hypoclorite/bleach)
O2 independent pathway
NADPH oxidase (enzyme activated by microbe) when phagosome fusion H/K enter alter pH, activates proteases (lytic enzymes like defensins)
Defensins
cationic proteins, cleave G+-, fungi, virus cell wall w/out O2,
NK cells
interleukin, interferonA/B (cytokines) enhance NK then NK produce TNF/interferon gamma (recruit T cells), release perforins (pores in target) and granzymes (cell lysis thru pores)
Inhibitory receptors (NK)
detect class I major histocompatability complex (MHC) proteins on all healthy cells and inhibit NK
Activating receptors (NK)
activate cytotoxic mechanisms
Antibody-dependent cellular cytotoxicity (ADCC)
antibody coated lysed (tumor), no phagocytosis or complement
Innate Lymphoid cells (ILC)
mucosal sites, release immunoregulatory cytokines, Interferon gamma (produce superoxide and H peroxide)