(PM3A) Core Immunology Flashcards
What is the role of the immune system?
Combat infection
What is an infection
Parasitism by microbes
What are the body’s barriers to entry against microbes?
- Skin
- Gastro-intestinal tract
- Genitourinary tract
- Respiratory
- Mucous lining
(1) What groups of drugs are likely to be prescribed for a transplantation?
(2) Why?
(1)
- Glucocorticoids
- Anti-proliferatives
- Calcineurin inhibitors
(2) They are immunosuppressants - prevent rejection
(1) What groups of drugs are likely to be prescribed for an autoimmune condition?
(2) Why?
(1)
- Analgesics
- Glucocorticoids
- Anti-proliferatives
- Calcineurin inhibitors
(2) Symptom management + immune suppressants
- Reduce undesirable effects of immune response
What groups of drugs are likely to be prescribed for activation of the immune system?
(1) Vaccines
(2) Immune stimulators
What groups of drugs are likely to be prescribed for controlling hypersensitivity reactions?
- Antihistamines
- Glucocorticoids
FOR SYMPTOM MANAGEMENT
What groups of drugs are likely to be prescribed for cancer?
- Checkpoint inhibitors
ø PD1
ø CTLA-4 - Cancer vaccines
- T cell immunotherapy
What are checkpoint inhibitors?
A cancer treatment
Blocks some proteins (called checkpoints) of some immune/ cancer cells
What are the core concepts of immunology?
(1) Innate
(2) Adaptive
(3) Antigen specificity
(4) Lymphocytes
(5) Effector mechanisms
(1) How many main types of immunity are there in vertebrates?
(2) What are the main types of immunity in vertebrates?
(1) 2 types
(2)
- Innate immunity
- Adaptive immunity
What are examples of the innate immunities present in vertebrates?
- Evolved defence against microbes
- Barriers: Skin/ stomach acid
- Sequestration of nutrients
- Antimicrobials: e.g. lysosome
- Acute inflammation - tissue & cellular injury
- Antiviral responses: e.g. interferon
- Specific innate microbial recognition
What are the main giveaways of an acute inflammatory response? dcrt
(1) Dolor - Pain
(2) Calor - Heat
(3) Rubor - Redness
(4) Tumor - Swelling
What triggers/ causes acute inflammation?
Tissue/ cellular injury
Is tissue repair and healing part of the immune response?
No
How are microbes recognised by the body?
PAMP are different
(Pathogen Associated Molecular Patterns)
What is a lipopolysaccharide?
An endotoxin
LPS
What is Toll-like Receptor 4?
The receptor binding site for endotoxins/ lipopolysaccharides (LPS)
What are examples of the adaptive immunities present in vertebrates?
- Learned problems to antigens
- Memory
- Lymphocyte responses
- Expansion of specific T and B cells
- Production of antibodies
When are antibodies produced?
Following infection/ presence of a pathogen stimulating an immune response
Following ‘priming’.
With reference to immunology, what does ‘priming’ mean?
Contact of an immune cell with the antigen present on a pathogen/ microbe
What is the basis for adaptive immunity?
Antigen recognition
How do antibodies bind to specific antigens?
Variable region binds to antigen
Bonding includes:
- Hydrophobic
- Hydrophilic
- Van der waals
- Hydrogen
- Electrostatic
High affinity
Stable
What is an MHC?
Cell of the immune system of vertebrates
Major histocompatibility complex
Define epitope.
The part of an antigen that the antibody binds to
What are lymphocytes? Give examples of lymphocytes.
Type of white blood cell in the vertebrate immune system
ø B cells - produces antibody
ø T cells - respond to peptides
Where do lymphocytes reside?
- Blood
- Lymph nodes
- Bone marrow
How do B cells (B lymphocytes) recognise antigens?
Directly bind to antigen
via receptor on pathogen cell surface
What is a B lymphocyte?
B cell
Produces antibodies
Matures into plasma cells
How do T cells (T lymphocytes) recognise antigens?
Bind the antigen peptide (epitope) to MHC on surface of dendritic cell
What is a T lymphocyte?
T cell
Type of white blood cell in the vertebrate immune system
What is a dendritic cell?
Antigen presenting cell
(1) How many life stages do lymphocytes have?
(2) What are they?
(1) 3
(2)
Generation:
- Enable body to recognise anything
Priming + Replication + Clonal expansion:
- Learn what to respond to
- Memory
Effector function:
- Recognise and kill microbes/ pathogens
where are lymphocytes derived?
Derived from bone marrow cells
Selected based on safe and effective function
How do lymphocytes learn what to respond to?
Each one only recognises one specific peptide in new pathogen/ microbe
How many times does a single T cell replicate?
≥20 times
In first 2-3 weeks
What are lymphocytes primed by? dc
Innate stimulation of dendritic cells
With reference to immunology, what are effector cells?
T cells (lymphocytes)
B cells (lymphocytes)
What do effector T cells differentiate to?
(1) Helper T cells
(2) Killer T cells
What are the types of T lymphocyte?
(1) Killers: Direct killing of virally infected cells
(2) Helpers:
ø Cytokine release -> Inflammation
ø Control B cell antibody response
(1) What effect do antibodies have on bacterial toxins?
(2) What type of antibody has this direct effect on bacterial toxins
(1) Inactivates them
(2) Binding and blocking antibodies
- IgG
- IgA
Which specific antibodies can bind and inactivate toxins?
- IgG
- IgA
What mechanism of action do IgG and IgA antibodies have on viral infections?
Binding and blocking antibodies
Directly block viral infection
What happens to a pathogen when IgG and IgM bind to an antigen on its surface?
Activates on antigen
Punches holes into cell wall
Directly kills
Name some types of histamine antibodies.
Mast cells
What antigen do mast cells have on the surface?
IgE
What does recognition of IgE antigens trigger?
Histamine release
What receptor do histamines recognise?
IgE
What is IgE?
Immunoglobulin E
Histamine antibody
What is IgG?
Immunoglobulin G
Phagocytosis, direct killing & binding and blocking antibody
What is IgA?
Immunoglobulin A
Binding and blocking antibody
What is IgM?
Immunoglobulin M
Direct killing antibody
What are the types of T lymphocyte?
(1) CD8 Killer cells
- Directly kill virally infected cells
(2) CD4 Helper cells
- Trigger inflammation
What is the mechanism of action for an MHC?
Binds to a peptide in the virally infected cell
Takes the peptide to a CD8 killer T cell receptor where it is recognised
What is the mechanism of action of a CD8 killer T cell?
Binds to a peptide from an infected viral cell
Recognises and directly kills virally infected cells
What is the mechanism of action of CD4 helper T cells?
Macrophage phagocyte encounters bacterial pathogen
MHC (on B cell) presents peptide from bacterial pathogen to CD4 helper T cell
Recognition of bacterial peptide triggers pro-inflammatory mediator release
Triggers large-scale antibody release from B cells
What is the condition that destroys all CD4 T cells?
HIV - causes AIDS
What is experimental gene therapy?
Experimental technique
Uses genes to treat or prevent disease
What is SCID?
Severe Combined Immunodeficiency
Group of rare disorders - caused by gene mutations in immune cells
What is the intention of experimental gene therapy? ic
To increase activation of immune cells (lymphocytes)
What is the basic mechanism of action of vaccines? ps ir
Activation of pathogen specific immune responses
What is the effect of recombinant cytokines?
Activate inflammatory response
What is the effect of synthetic innate stimulatory drugs?
Activate inflammatory response
What are the types of antigen on a pathogen/ microbe?
(1) Structural antigens
(2) Short-peptide antigens
