Overview of the Immune System Flashcards
Where are the primary and secondary lymphoid organs
Primary lymphoid (developmental of WBCs -BM, thymus
Secondary lymphoid (traps antigens, initiation site of adaptive response)
- nasopharyngeal LN
- tonsils
- bronchial
- peripheral
- spleen
- GALT
Describe the circulatory route of the lymphocytes
- Naive T cells
- Central memory T cells
- Effector memory T cells
- Tissue resident memory T cells
Naive T cell, central memory T cell
-Blood + SLO (enter tissues when activated)
Effector memory T cell
-Blood + SLO + tissue
Tissue resident memory T cell
-Tissue
Describe the function of each element of the innate immune system
- epithelial barriers
- complement
- phagocytes
- PRRs and MHCs on APCs
- MHCs on our own cells
- chemokines
- cytokines
Epithelial barriers => physical defence
Complement => liver produced proinflammatory, bind to non self -AB-AG -MBL -Alt pathway All converge onto C3 pathway and -opsonize -increase inflammatory response -microbe lysis
Phagocytes
-neutrophils, NK cells, macrophages phagocytose opsonised foreign material
PRRs on APC
-present PAMPs, DAMPs => cytokine, chemokine release, proinflammatory
MHCIIs on APC => present to Th
MHCI on self cells => present to CD8
Chemokines => recruit cells to inflammatory sites
Cytokines (interferons, interleukins) => activate, suppress, modify response in an autocrine/paracrine fashion
Describe the function of each element of the adaptive immune response
- antibody
- T cell receptor
Antibody (made by plasma cells, bind to specific antigens)
- Fc => interact with self cell molecules (complement, CD8) => microbe killing
- AB site => binds to specific AG
- neutralisation
- agglutination
- precipitation
- complement fixation
T cell receptor
- specific to protein presented on MHC of self cells/APCs
- signal 1 - MHC=TCR
- signal 2 - costimulation => T cell activation, proliferation
What are the key differences between the innate and adaptive response
- development
- speed
- duration
- specificity
- memory
- key molecules
- key cells
Innate
- from birth
- rapid
- short
- low
- none
- complement, enzymes
- phagocytes, NK
Adaptive
- increases with exposure
- slower
- long
- high
- long lasting
- AB, cytokines
- B, T cells
What triggers inflammation
What is the purpose of inflammation
Triggers
- trauma, necrosis, physical, chemical agents
- foreign body
- infections, toxins
- hypersensitivity
Effects
- alert to threat of injury
- neutralise, destroy cause
- prepare for repair, reduce damage
- LEADS TO IMMUNE RESPONSE, CANNOT HAVE IMMUNE RESPONSE WITHOUT INFLAMMATION
Describe the initial inflammatory response
Name the 5 inflammatory mediators that all interconnect with each other
VD, increased blood flow, metabolism=> rubor, calor
Increased permeability, chemotaxis, soluble mediators => edema, dolor
Complement Bradykinin Coagulation Arachidonic acid Free radicals
What are the 3 main proinflammatory cytokines
What do they do
IL6
- increase VD, vascular adhesion molecules
- DC maturation
TNFa, IL1
-do the same AND increase vascular permeability
What are the 4 phases of acute inflammation
Initiation
Amplification
Destruction via phagocytosis
Termination mediated by anti inflammatory mediators
Describe the arachidonic acid route in the membrane phospholipid pathway
- what drug inhibits this pathway
- COX pathway
- what drug inhibits this pathway
Membrane phospholipids =(phospholipase)=> arachidonic acid
-inhibited by steroids
Arachidonic acid =(COX)=> prostaglandins
-inhibited by NSAIDs
Prostaglandins
- increase permeability, VD
- neutrophil chemotaxis
Prostaglandin => thromboxane
-platelet aggregation, VC
Describe the arachidonic acid route in the membrane phospholipid pathway
- what drug inhibits this pathway
- lipoxygenase pathway
Membrane phospholipids =(phospholipase)=> arachidonic acid
-inhibited by steroids
Arachidonic acid =(lipoxygenase)=> leukotriene
Leukotriene A4 => B4
-neutrophil chemotaxis
A4 => C4, D4, E4
- slow reacting substance of anaphylaxis (
- bronchial SMC
Describe the arachidonic acid route in the membrane phospholipid pathway
- what drug inhibits this pathway
- platelet activating factor pathway
Membrane phospholipids =(phospholipase)=> lysoplatelet activating factor
-inhibited by steroids
LPAF => PAF
- platelet aggregation
- eosinophil chemotaxis
- neutrophil activation
What are the key differences between acute and chronic inflammation
- specificity
- immune response
- characterisation
- resolutions?
Acute
- non specific
- innate
- cardinal signs
- resolves or evolves into chronic
Chronic
- specific
- innate, adaptive
- fibrosis, granuloma, angiogenesis
- repetitive cycle: increased disease <=> increased recruitment
