Module 5 Immunocellular Alterations Flashcards
Innate Immunity
- Physical protective barrier of skin & mucosal surfaces
- Automated response to physical/infectious injury
Processes
- Phagocytosis
- Inflammation
- Complement activation
- Coagulation
Stratum Corneum
- Physical impermeable barrier
- Works with granular & spinous cell layer
- Corneocytes embedded in lipid matrix
Sebaceous Gland
- Secrete sebum
- Coats skin in antimicrobial lipid
Physical Barrier
- Acidic pH
- Antimicrobial lipids & peptides
- Disrupt bacterial membranes
Mucosal Surface Barrier
- Bacteria trapped in mucus
- Mucus contains antimicrobial peptides & secretory IgA
Goblet Cells
- Attract bacteria
- Intestinal
Skin Infection Barrier
- Keratin
- Mucous
- Tight junctions between epithelial cells
Microbe Death via Antibiotics
- Defensins
- Dermcidin
- Acidic pH
- Sebum
Epithelial Functions
- Portals of entry of microbes
- Provide physical barriers
- Produce antimicrobial substances
- Harbor lymphocytes
- Kill microbes & infected cells
Granulocytes
- Multi-lobed nucleus
- Spotted surface (protein, peptides)
- Cytoplasm packed with granules
- Granules loaded with antimicrobial enzymes
- All contribute to innate immunity
Polymorphonuclear Cell (PMN) /Neutrophils
- Recognized by multi-lobed nucleus
- 60% of bone marrow
- Develop within bone marrow
- 10hr lifespan
- 10^11 enter & leave circulation daily
Neutrophil Granules Function
- Kills bacteria by iron restriction
- Destruction of cell wall & membrane
- Oxidation
Phagocytosis
- Optimised by antibody
- Compliment protein binds to bacteria receptor
NADPH Oxidase System
- Electrons pumped into vacuole
- Convert oxygen into super oxygen animes
- Interact with protons to form hydrogen peroxide
- MPO reacts with hydrogen peroxide & halide (Cl, Br, I)
- Form toxic oxidizing agents (HOCl, OH,)
Chronic Granulomatous Disease
- Genetic defect X-linked & autosomal recessive
- Failure to produce cytochrome b558
- Unable to generate superoxide (NADPH Oxidase)
- Can’t kill bacteria, form granulomatous lump
Basophils
- Fight parasitic & allergic reactions
- Produce heparin (anticoagulant)
- Produce histamine (vasodilator)
- Initiate chronic allergy & anaphylaxis
Eosinophils
- Fight parasitic infection
- Pathology of asthma
- Produce reactive oxygen species
Macrophage Lifespan
- Emerge from bone marrow as stem cell
- Circulate as monocytes
- Migrate into tissue (differentiation) take up properties
- Activated macrophage
- Inject microbe
- Life span several months
Macrophage Function
- Efflux of iron & manganese (nutrition)
- Influx of copper & zinc (support oxidate killing)
- Produce nitric oxide synthase
Pattern Recognition Receptors
- Recruitment of adapter proteins
- Recruitment & activation of protein kinases
- Activation of transcription factors
- Gene transcription
TLR 1, 2, 6
- Peptidoglycan
- Lipoproteins
TLR 4
- Bacterial LPS
- Fungal mannans
- Viral envelope proteins
TLR 5
- Bacterial flagellin
TLR 3, 7, 8, 9
- Microbial & viral nucleic acids
Innate Immunity Specificity
- Structures shared by classes of microbes/damaged cells
Innate Immunity Receptors
- Tool-like
- N-formyl peptide
- Mannose
- Scavenger
- Identical on each cell
Adaptive Immunity Specificity
- Structural detail of microbial molecules
- May recognize nonmicrobial antigens
- Distinct antibody molecules
Adaptive Immunity Receptors
- Encoded by genes
- Produced by recombination of gene segments
- Greater diversity
- Clonal distribution
Cytokine Production
- Complement
- Microbe engagement of toll receptors
Cytokine Function
- Modify functionality of immune cells & vascular endothelium
TLR Engagement
- Immune cells produce cytokines & chemokines
Tumour Necrosis Factor (TNF)
- Macrophages & t cells
- Endothelial & neutrophils activation
- Hypothalamus fever
- Upregulate expression of adhesion proteins
Interleukin -1 (IL-1)
- Macrophages & endothelial cells
- Endothelial activation (inflammation/coagulation)
- Hypothalamus fever
Chemokines (IL8)
- Macrophages, dendric cells
- Activated endothelial cells
- Attract neutrophils
Chemokines Function (IL8)
- Upregulate oxidative capacity
- Change in shape
- Promote adhesion to endothelium
- Promotes granulation (protein to surface)
Interleukin -12 (IL12)
- Dendritic cells & macrophages
- Act on t & NK cells
- IFN production
- Activate macrophage killing capacity
Interleukin-10 (IL-10)
- Macrophages, endothelial cells, T cells
- Inhibit IL-12 production
- Anti-inflammatory