Please enable JavaScript.
Coggle requires JavaScript to display documents.
INNATE IMMUNITY - Coggle Diagram
INNATE IMMUNITY
-
-
DEFINITIONS
THREE LINES OF DEFENSES
- First line: Non-specific barriers (broad, external defense)
- Second line: Non-specific innate immunity (broad, external defense - patrolling immune cells such as mast cells)
- Third line: Specific immune system (humoral and cell mediated)
FEATURES OF INNATE IMMUNITY
- Genetically determined
- No prior contact
- 2nd line defence against infection
- Roles: Clean up debris, repairing damage tissues, Kill invading microbes, Activate adaptive immune response
- Non-specific and specific
COMPLEMENT SYSTEM
DEFINITION
- Secreted system of innate immunty
- Complement: Group of 30 serum proteins, involved in activation 'cascade'
MAJOR FUNCTION
- Opsonization: increase phagocytosis
- Chemotaxis: attract phagocytes/neutrophil
- Anaphylatoxin: Increased blood flow, capillary permeability
- Cell lysis
COMPLEMENT CASCADE
- Step in which protein component takes turn in precise chain
CLINICAL ASPECT
- Acute glomerulonephritis and SLE:
- Soluble Ag-Ab complexes activate classical pathway
- Found in autoimmune conditions
- Immune complexes bind complement, complement levels are low in immune complex diseases
- Transfusion mismatch
- Ab to A Ag in recipient binds to A Ag on donor red cells
- Activate complement, large amount of anaphylatoxins and membrane attack complexes are generated
- Anaphylatoxins cause shock, membrane attack complexes cause hemolysis
CYTOKINES AND CHEMOKINES
DEFINITION
- Cytokines: Soluble proteins that mediate: Immune reactions, Inflammatory reactions, Comm between leukocytes
CLASSIFICATION
- Interleukins: Cytokines made by one leukocytes, acting on other leukocytes
- Chemokines: Chemotactic activities
- Interferons: tissue antiviral cytokines
- TGF: growth, stimulate
- TNF: induction of apoptosis
MECHANISM
- Inducing stimulus: gene transcription for soluble protein in cytokine-producing cell -> Cytokines binds to receptor on target cells -> Binding generates signal -> changes in gene transcription and gene activation -> biological effect
ACTS IN 3 WAYS
- Autocrine action: same cell
- Paracrine action: nearby cell
- Endocrine action: Circulate in bloodstream
BACTERIAL SEPTIC SHOCK
- Bacterial endotoxins cause massive release of TNF and IL-1 (pro inflammatory cytokines) by activated macrophages)
- Increased vascular permeability
- Severe drop in blood pressure
- 10% mortality
CYTOKINE STORM
- Balance between sufficient cytokine production and immune response to eliminate the pathogen
- Sustained production of cytokines, leads to elevated circulating levels, necessary to appropriately control some disseminated infections
- Increased levels, cytokines can have systemic effects, cause collateral damage to vital organ systems