Immunity* Flashcards
Antigens - definition? epitope definition?
Definition:
- any substance capable of triggering an immune response
Epitope is the area of the antigen which the antibody attaches to (gives identity either self or non-self)
Physical barriers - skin definition? mucus (production? produced from? composition? immune characteristics?) self-tolerance definition?
Adaptive and Innate (no answer and cells?)
Skin:
- is a barrier between internal and external
Mucus:
- produced by goblet cells in the resp tract and transported by cilia
- consists of 95% water, 2% salts and 2% mucin and is sticky
- also contains antimicrobials such as growth inhib, enzyme inhib, lysins and abs
Self-tolerance:
- elim lympho which react with self antigens during early development to be destroyed
Non-specific humoral factors - growth inhibitors (function? examples? dependent?) enzyme inhibitors (function and example?) lysins (function and example?)
Growth inhibitors: - deprive microbes of nutrients for growth - Transferrin (bind iron) and Interferon (antiviral) - temp dependent Enzyme inhibitors: - prevent enzymes from doing their job - poison or drugs Lysins: - lysis - lysozyme and complement
Complement system - classical? alternative? lectin?
(describe each pathway) MAC?
Alternative pathway: - C3 clipped and forms C3a and C3b - C3b reactive (neutralised by H2) - C3b stabilised and binds to prot B - prot B clips B to form C3bBb - C3b can bind C3 convertase forming C3bBbC3b - C5 convertase Classical: - C1 formed from C1q/r/s - C1q binds Ab and C1r/s are proteases - bind to C1q; act of C1r and act of C1s - C1s cleaves C4 to C4a/b - C4 homologous to C3 - C2 binds to C4b forming C4b2b - C3 convertase - C3 bind to C3b2b making C4b2b3b - C4 convertase Lectin: sugar binding prot - triggered by Ab absence - needs plasma mannose-binding lectin - ficolins (similar to C1q) bind lectin assoc serine proteases (sim to C1r/s) and cleave C2/4 - then identical to classical MAC: membrane attack complex - C5 convertase clips C5 - C5 binds with C6/7/8/9 to form MAC - C9 pore and the rest the stalk - C5 converts C5 into C5a/b, but stays on cell surface - C7/8/9 bind in succession to C5b - C5b/6/7/8 and C9 form MAC
Membrane attack complex - safeguards for self cells? opsonisation? chemo-attactrants?
Safeguards: - decay acceleration factor (DAF) which accelerates breakdown the C3bBb - CD59 compete MAC before attachment Opsonisation: - C3b clipped by a serum prot to form iC3b - macrophages can bind to iC3b Chemoattractants: - C3a/C5a recruit macro and neutrophils - anaphylatoxins
Pathology defintion - understanding and provide basis?
The study of disease:
- understanding how they develop and progress
- provide basis for treatment selection
Understanding disease - key words?
Aetiology
Pathogenesis
Prognosis
Aetiology defintion?
Cause of disease:
- genetic and environmental factors
Pathogenesis defintion?
How an individual disease develops and progresses
Mechanisms of disease (inflamm, neoplasms and circulatory disorders)
Types of basic pathological mechanisms (inflamm? Neoplasia? Circulatory disorder?)
Inflamm: - acute - chronic Neoplasis: - benign - malignant Circulatory disorders: - thrombosis - embolism - infarction
Inflammation - acute vs chronic?
Acute: - neutrophils polymorph mediated - healing and repair - abscess formation Chronic: - lymphocyte - macro - plasma cells
Neoplasia - benign vs malignant?
No cancer
Cancer
Diagnostic pathology - what gives them info? Can aid to give a?
Macroscipic, microscopic and molecular examination of tissue samples
- biopsies
Clinco-pathological correlation
Professional phagocytes - types? function?
Types: - monocytes - macrophages - granulocytes - dendritic cells Function: - phagocytosis
Phagocytosis - process?
Process:
- engulfs the bacterium into a small vesicles called a phagosome
- phagosome fuses with a lysozyme to form a lysosome
- lysosome kills the bacterium
- also release debris
Macrophages - differentiate from? Differentiate into? Found in the? Travel to? Activation causes? 3 states of readiness?
From: - bone marrow stem cells Differentiate into: - monocytes then macrophages on the tissues Found: - in the tissues Travel: - into the capillaries and hang around waiting for pathogens Act: - chemicals released causing redness and swelling Readiness: - resting (low MHC 2 levels) - primed (higher MHC 2 levels) - APC (engulf pathogen)
Neutrophils - most abundant? Name derivative? Profession phagocyte? Life span? Fucntion? Not APC? Acute inflammation (follow what?)
Most: - WBC Name: - neutral pink Professional: - most important Life span: - 5 days Function: - phagocytosis but not APC Acute inflamm: - migrate towards site of inflamm via BVs CIA interstitial fluid, following trail of chemokines via chemotaxis
Natural killer cells - differentiate from? types of NK cells? Found where? Function and kill what? 2nd function (FasL?) Cell recognition? Activation of NK cells (given off by?) Cooperation (macrophages secretion? LPS? IL-12? IL-2?)
Diff:
- stem cells in BM
NK types:
- have diff properties
Found:
- blood and spleen
Function:
- kill tumour cells, virus infected cells bacteria, parasites and fungi
- form a MAC (secrete perforin)
2nd function:
- FasL interact with Fas in target cell connectiong and causing the cell to die
Cell recog:
- activation and inhibition receptors
- inhibotry receptor recognises MHC I, found on all human cells
- activated of the target cell doesn’t express MHC I
Activation:
- IFNa/b givej off by cells under viral attack
- secrete IFN-y
Cooperation:
- LPS creates hyperact of Macro
- macrophages produce IL-12 and TNF to increase IFN-y secretion to increase activation
- NK produce IL-2 (GF) and Macro induce receptor on NK
Inflammaptey response - defintion? Acute vs chronic?
Def:
- battle that macrophages, neutrophils and other immune systems wage against invader
Acute:
- initial response of body to harmful stimuli
Chronic:
- progressive shift in type of cells at inflamm site characterised by simultaneous destruction and healing of tissue from inflamm process
Adaptive immunity - defintion? recognition of antigens (B and T lymphocytes recog specific epitopes?)
Def:
- specific and immunological memory
Recognition:
- B and T lymphocytes
- B cells recog free organic antigen via BCR (surface IgM)
- T cells need to be shown antigen with MHC via TCR
T lymphocytes - Name? Function? Types? CD4 (functions?) CD8?
Name: - thymus derived T cell Function: - CD4 stimulate B cell to produce antibodies - CD8 are cytotoxic CD4: - activate other immune cells - B cell ab class switch - activation and growth of Tc CD8: - exposed to infected cell release perforin forming a proe and release granzyme B and induce apoptosis
Function of MHC I and II - found on? presents what (act which response)?
Found on:
- MHC I; all nucleated cells
- MHC II; all APCs
Present:
- MHC I; present virally induced peptides to CD8 T cells and trigger cytotoxic response
- MHC II; present Ag to CD4 T cells and activate macro and B cells
T cell selection - basis? positive? negative selection? Clonal expansion process? T cell memory?
Basis:
- must learn to not recognise self antigens
Positive:
- thymocyte undergoes TCR gene rearrangement
- positive selection of receptors for MHC (CD3/4/8)
- forming CD4 and CD8
Negative:
- death of cells with high affinity for self antigens
Process:
- immature T cell binds to an APC forming CD4 abd CD8
- CD4 can activate B cells or activate more macrophages
Memory:
- from fully differentiated T cells
B cells and antibodies - cell type? production of? b cells express? Tolerance?
Type: - from BM and mature into plasma cells Production: - for abs production B cells: - express sIg on the B cell Tolerance: - tolerise T cell than B cell because B cells can't produce abs without T cell help
Antibody structure - 2 parts? light chain types? heavy chain (function? regions? 5 types of heavy?) flexibility?
2 parts: - ag binding region (Fab) - fc region Chains: - light; lambda and kappa - heavy; define Ig, constant region (same for all Ig class) and a variable region (differ between B) - gamma, delta, alpha, u and backwards 3 Flexibility: - hinge region allows flexibility
Antibody classes - IgM? IgG? IgA? IgE? IgD? - (function of each?)
IgM: - fixing complement and opsonisation IgG: - opsonisation IgA: - protect mucosal surface and resistant to stomach acid IgE: - defends against parasites causes anaphylactic shock and allergies IgD: - naive B cell antigen recep
Functions of abs - neutralisation? opsonisation? complement activation?
Neutralisation:
- abs neutralise the biological effects of the antigen (stop antigen binding)
Opsonisation:
- chemically modified to have stronger interactions with cell surface receptors on phagocytes and NK cells (C3d bind to pathogen act B cell)
Anaphylactic shock - cell type? express recep? allergic act? release of?
Cell:
- mast cell
Express recep:
- IgE
Act:
- inactive until an allergen binds to IgE
- binding of 2 or more IgE required to act mast cell
- clustering of the IgE causes a complex sequence of reactions (release of histamine and heparin)
Immunological memory - secondary response features? why it occurs? memory B better?
2nd response:
- rapid
- larger and often qualitatively different
Why:
- each exposure causes an expansion in the clone of lymphocytes and differentiate to memory cells
B:
- memory B cells produce abs but with higher affinity than naive and rapid
Active and passive immunity definitions? subtypes of active and passive (natural and artificial?)
Active: - conferred by a host response to a pathogen Passive: - conferred by adoptive transfer of abs or T lymphocytes specific for the pathogen Natural active: - during infection Artificial active: - injection or orally (long lasting immunity) Natural passive: - mother to child Artificial passive: - abs given for a fatal disease Passive: - memory cells only temp
Autoimmunity - definition? treatment? theories (clonal deletion? clonal anergy? idiotype network/)
Def:
- triggered to attach the tissues of the host
Treat:
- immunosuppression
Clonal deletion:
- self-reactive lymphoid cells destroyed during development of immune system
Clonal anergy:
- self-reactive T/B cells become inactivated in normal individuals
Idiotype network:
- network of bas capable of neutralizing self reactive abs naturally within the body
Vaccinations - inactivated? acellular? attenuated? subunit? DNA? (definitions?)
Inactivated: - pathogen particle destroyed and can't divide but can be recognised and evoke immunity Acellular: - cellular material with antigenic parts Attenuated: - reducing pathogen virulence Subunit: - part of virus DNA: - injecting genetically engineered DNA
