Immunology 1 Flashcards
why is immunology complex?
Vital – 100% essential for life!
Potent- can kill in seconds
Multiple elements and systems
-replicated elements and systems
-interconnected elements and systems
Variation in humans
Variation in microbial pathogens
why is it important to be aware of the complexity of immunology?
Manipulating immune system can have severe side effects
Multiple therapeutics may be needed to treat a single disease
A single therapeutic can have variable efficacy
Some conditions are difficult to treat
Explains gulf between management and cure
what is an immune system?
All parts of the organism that combat infection
what are the 2 parts of immune system?
Innate immunity (most important)
Adaptive immunity (most complicated)
what are the 5 diseases categories
EXAM
Infection, Hypersensitivity, Autoimmunity, Transplantation, Cancer
Divide up therapeutics:
Activate vs inhibit
Cure vs block vs soothe
what are the 5 concepts of immunology?
Innate, Adaptive, Antigen Specificity, Lymphocytes, Effector Mechanisms
explain the concept innate?
Evolved defences against all microbes
Barriers- skin, acid
Sequestration of nutrients
Antimicrobials- lysozyme
Tissue and cellular injury: acute inflammation
Antiviral responses- interferon
Specific innate microbial recognition – born with it
what is innate response to cellular and tissue injury
acute inflammation
Innate response to cellular and tissue injury
Pain, Heat, Redness, Swelling
what an acute inflammation be triggered by?
Triggered by tissue or cellular injury
Very many mediators including: Complement, Clotting, Kinin system, Histamine, Eicosanoid pathway
Acute imflammation
Innate response to cellular and tissue injury
LINKED TO BUT SEPARATE FROM IMMUNE SYSTEM
Can be CONFUSING- many components involved in BOTH tissue repair and healing
AND immune response to pathogens/infection
how is innate microbial recognition work
Key: mammals have unique biochemical makeup; microbes look fundamentally ‘different
Classic example:
LPS, endotoxin, lipopolysaccharide
Bacterial cell wall component
(gram negatives e.g. E. coli)
explain the concept adaptive ?
Learned response to ‘antigens’
Memory
Characterised by Lymphocyte responses
Expansion of specific T and B cells
Production of antibodies
what is the difference between adaptive and innate immunity?
Innate :
Recognition/ specificity: Microbes, injury, At any time, Always the same
When learnt: evolutionary time
how : many mechanisms
Adaptive
Recognition/ specificity: Anything: “ANTI GEN, Only after “priming” , Memory of encounter
When learnt: Lifetime of individual- does not pass on
how : antigen recognition
antigen specificity:
What can the adaptive immune system learn to recognise?
anything (almost)
structures (antibodies) - 2 binding sites
peptides more than 8 or 8 amino acids (T cell receptor)
Read and recognize peptides (broken down protein)
what are Structural antigens are recognised by
antibodies
Variable region binds to antigen via mixture of hydrophobic/hydrophilic, electrostatic, hydogen bonding, van-der-waals interactions
Binding high-affinity and stable - strongest
Not always specific! Some binding sites shared
Peptide antigens are recognised by what receptors
the T cell receptor
Proteins are made up of many overlapping peptides For 8mer, theoretically 208 different ones!
Peptide is ‘sandwiched’ between MHC molecule and T cell receptor
what is the role of lympocyte and examples
Lymphocytes have to enable the adaptive immune system to:
recognise any antigen
‘learn to respond’ and ‘remember’
kill microbes
B cells (make antibody)
T cells (respond to peptides)
Live in blood, lymph nodes, bone marrow
Both have random, clonal antigen receptors
what is the role of b cells
make antibodies
what is the role of T cells
responds to peptide
how does B cell recognise antigen?
Directly bind antigen via antibody molecule on surface of cell
how does T cell recognise antigen?
Bind antigen peptide on MHC molecule bound on surface of dendritic cell (DC)
what are the three life stages of lympocytes?
Generation, selection
Enabling the body to recognise anything
2 Priming, replication, clonal expansion
Learning what to respond to - and remembering
3 Effector function
Recognising and killing microbes
explain generation of lymphocytes
Lymphocytes –like other blood cells - are derived from bone marrow cells but they are totally unique – their genome is randomly rearranged to give each cell a single antigen receptor
But after rearranging, lymphocytes are selected for safe and effective function – “tolerance”
innate signals control what responses
adaptive
what is the effector mechanism
Types of antibody
Binding and blocking
Histamine
Phagocytosis
what are the types of T cell and their role
Killers: Direct killing of virally infected cells
Helpers: Cytokine release and inflammation
Helpers: Control B cell antibody responses
what are the antibodies which is responsible for activating and blocking
Toxins can be bound and inactivated by
antibodies can directly block viral infection
Antigen bound by IgG and IgM activates ‘complement’ which can punch holes in cell walls
types of antibodies - histamine
Mast cells are ‘sentinels’ coated with IgE
Antigen recognition triggers histamine release
Macrophages are coated with receptors for IgG and rapidly phagocytose antibody bound to antigen
type of T lymphocyte
CD8 Killers: Direct killing of virally infected cells
CD4 Helpers: Trigger inflammation
Central role for CD4 helper T lymphocytes
1 Antigen bound by B cell antibody
2 B cell presents peptide derived from antigen
3 Peptide recognition by CD4 helper on B lymphocyte triggers activation signals to B cell
4 High levels of antibody against same antigen that peptide was derived from
what is AIDS caused due to
AIDS is caused by destruction of all CD4 T cells by HIV
what are the interventions for transplantation
Transplantation
Glucocorticoids
Antiproliferatives
Calcineurin inhibitors
Other immunosuppressants
what are the interventions for autoimmunity
Analgesics
Glucocorticoids
Antiproliferatives
Calcineurin inhibitors
Other immunosupressants
+ Symptom management
interventions for Activating the immune system
Vaccines
Immune stimulators
what are the interventions for cancer
Cancer
Checkpoint inhibitors
Cancer vaccines
T cell immunotherapy
what are the interventions for Controlling hypersensitivity reactions
Antihistamines
Glucocorticoids
+ Symptom management
