Immune System Flashcards
What is the immune system?
A versatile defence system that protects us from diseases caused by pathogenic microbes
How many lines of defence do we have?
3
Which lines of defence protect us from anything (non-specific) foreign coming into our bodies?
First and second line
Describe the first line of defence.
A physical barrier against foreign bodies and microbes, created by the skin and mucous membranes
What does innate mean?
Inborn / natural
Describe the third line of defence.
The advanced part of our immune system, which targets SPECIFIC foreign bodies
Describe the second line of defence.
A non-specific immune response, which includes some immune cells, proteins, fever and inflammation.
Which line of defence targets specific foreign bodies?
The third line
Which lines of defence target non-specific foreign bodies?
First and second line
Which lines of defence make up our innate immunity?
First and second line
A fever is part of which line of defence?
The second
What is the purpose of a fever?
To create an unfavourable environment for most pathogens (too hot).
What is the purpose of inflammation?
To create an unfavourable environment for most pathogens.
List 3 signs/symptoms of inflammation
Redness, pain, swelling
List 2 things that can cause inflammation.
- Localised physical trauma
2. An infectious pathogen, trying to cause disease/damage.
Why is inflammation part of the second line of defence?
Because it is non-specific, and targets anything that is foreign.
Which line of defence is known as specific / adaptive immunity?
The 3rd line of defence
In which line of defence are memory cells created, in order to protect us from specific pathogens?
The 3rd line of defence
Why can we often get infected with a particular virus more than once?
Because viruses mutate (i.e, the flu).
Name 1 virus that frequently mutates
Influenza (flu)
What is a pathogen?
An infectious organism that can cause disease in a host
List 4 ways in which infectious organisms / pathogens can get into the body
- Through breaks in the skin (i.e, a cut)
- Via inhalation
- Via swallowing
- Via the eyes
How does the digestive system provide first line defence against pathogens?
- Saliva contains antibodies
- Stomach acid provides a very unfavourable environment to most pathogens (but not if stomach acid is low)
Name 1 thing that can cause reduced stomach acid and reduced salivary antibodies, in turn causing reduced immunity.
Stress
What is an antigen?
A cell marker (usually protein) that can be recognised by leukocytes.
How many types of antigen are there?
2
Name the 2 types of antigen
- Foreign antigens
2. Self antigens
Where would you find self-antigens?
On cell membranes (self antigens are cell membrane proteins)
Where would you find foreign antigens?
On microbes, bacteria, viruses, food, or drugs
What are antibodies?
Proteins produced in response to a specific antigen
Self antigens are produced through protein synthesis (transcription, translation and then embedding into cell membrane). True or false?
True
Which process are ‘transcription’ and ‘translation’ a part of?
Protein synthesis
What are foreign antigens?
Antigens not made by the body (i.e a bacteria or virus)
An immune response is created when ______ and ______ join together.
Antigens and antibodies
The ______ and _______ ________ are the first line of defence against pathogens.
Skin and mucous membranes
The skin acts as a physical barrier with its layers of tightly packed ________ cells.
Epithelial
How does the shedding of the epidermis layer of the skin contribute to our immune function?
When the epidermis sheds it also sheds any microbes that are on it.
How often is the epidermis of the skin entirely replaced?
Every 40 days
List 2 ways in which sweat contributes to immune function?
- It removes microbes from the surface of the skin
2. It contains IgA antibodies
Where would you find IgA antibodies?
Sweat, saliva, tears, breast milk
IgA = first letter of alphabet, first line of defence
What does Ig stand for?
Immunoglobulin
Immunoglobulins are antibodies. True or false?
True
What type of antibodies are found in sweat, saliva, tears, mucous secretions and breast milk?
IgA
How does sebum contribute to immune function?
It contains fatty acids which inhibit microbial growth (stop bacteria from undergoing mitosis).
List 3 places we find mucous membranes.
- The digestive tract
- The respiratory tract
- The urogenital tract
Saliva, tears and mucous secretions wash away microbes, and also contain anti- ________ substances.
Anti microbial
Name 2 body fluids that contain IgA and lysozymes
Tears and saliva
What are lysozymes?
Enzymes that break down bacterial cell walls
Where would you find the mucocilliary escalator?
In the respiratory tract
Tears are really important to provide an immune function on the surface of the eye. True or false?
True
Name 2 mucous secretions (substances secreted by mucous membranes).
Tears and saliva
What does the Ig in IgA / IgE / IgB, etc stand for?
Immunoglobulin
What is secretory IgA and how can it be measured?
Secretory IgA is the IgA present in the stool.
It can be measured via very comprehensive stool testing.
Why can IgA levels be used as an indicator of stress in a patient?
Because higher stress = lower IgA.
The more stressed a person is, the lower their IgA levels (and therefore general immune function) will be.
Vomiting and diarrhoea are rapid means of expelling _______.
Pathogens
Microflora generally outcompete pathogens for attachment sites on epithelial cell surfaces (the car parking spaces analogy), but where in the body / on which epithelial cell surfaces are they generally found?
In the large intestine
small intestine also, if SIBO is present
What is GALT?
Gut Associated Lymphoid Tissue
70% of our immune system is in the ______, in the form of _____
In the gut.
In the form of GALT (Gut Associated Lymphoid Tissue)
Which line of defence includes:
Complement System, Transferrins, Phagocytes, Natural Killer Cells, Inflammation, Cytokines and Fever?
2nd line of defence
List 4 mediators / factors in the second line of defence.
- Complement system
- Transferrins
- Phagocytes
- Natural Killer Cells
- Inflammation
- Cytokines
- Fever
What is the Complement System?
A series of proteins
List 2 outcomes produced by the complement system.
- Inflammation
2. Phagocytosis
What are transferrins?
Iron-binding proteins
Where are transferrins found?
In haemoglobin (Hb), in the blood. They are part of the Hb structure.
What do transferrins do?
They latch on to iron molecules and lock it away, stopping bacteria/pathogens stealing the iron for their own energy.
What are phagocytes?
White blood cells that specialise in engulfing / eating.
What are Natural Killer Cells?
Immune cells that release a protein called Perforin, which spears foreign cells, causing damage to the membrane and allowing water in, which in turn causes the foreign cell to rupture.
What is perforin?
A protein released by Natural Killer Cells
What do Natural Killer Cells do to foreign cells / pathogens?
They go around stabbing them and causing them to rupture! (Using the protein ‘perforin’)
Why is inflammation important?
Because it helps to attract white blood cells to the area (it’s a warning sign - a bit like pushing a fire alarm)
What are cytokines?
Messenger proteins that are released by cells
think of them as text messages to other cells
Which supplement can feed bacterial growth if not carefully controlled/monitored?
Iron
In adults, each Hb molecule contains ___ polypeptide chains; 2 x alpha and ___ x _____
4
2 x alpha, 2 x beta
How many polypeptide chains does 1 haemoglobin molecule have?
4
How many iron molecules can each haemoglobin carry?
4 (1 per polypeptide chain)
What is the complement system?
A defence system (involving cascade of events) made of over 30 proteins produced by the liver.
Where are the complement system proteins manufactured?
In the liver
Complement proteins are inactive and only become active when split into active fragments by ______
Enzymes
The main complement protein is known as ____.
C3
Whenever you see a letter after a complement protein (i.e, C3a and C3b), it means that protein is fragmented and active. True or false?
True
The most common way in which the complement cascade is activated is through the classical ________.
Pathway
What does the ‘classical pathway’ of the complement cascade involve?
An antigen and an antibody joining together
antigen-antibody complex
Give an example of a pathology that involves the classical pathway of the complement system.
Glomerulonephritis
(antigen-antibody complexes deposit on the kidney nephrons, causing inflammation and local damage, and subsequently loss of proteins into urine)
What is opsonisation?
The coating of a microbe with an identification protein
Collectively, complement proteins destroy microbes by:
- Promoting __________
- Contributing to ________
- Causing _______
- Phagocytosis
- Inflammation
- Cytolysis
How do complement proteins promote phagocytosis?
C3b fragments coat microbes in a protein (‘opsonisation’), which allows them to be identified as foreign by phagocytes and then engulfed.
In the complement system (second line of defence), complement protein fragments contribute to inflammation by binding to _____ cells and cause them to release ______
Mast Cells
Histamine
What is cytolysis?
Destroying (bursting) microbes
Which small protein hormones act as chemical messengers between different types of cells?
Cytokines
Cytokines are secreted by _________.
Leukocytes
What is the name given to the group of non-antibody proteins secreted by leukocytes?
Cytokines
Cytokines act on cells involved in _____
Immunity
Name 3 types of cytokines.
- Interleukins
- Interferons
- Tumour Necrosis Factor (TNF)
Interleukins are a type of _______
Cytokine
Interferons are a type of _____
Cytokine (Anti-viral proteins)
Which type of cytokine acts as a mediator between leukocytes?
Interleukins
Interleukins (cytokines) are mostly produced by ___-_____ cells.
T-Helper cells
Interleukin 1 (cytokine) is released by _______
Macrophages
Interleukin 1 (cytokine) is a protein hormone that tells your brain to ______ body temperature.
Increase
Interferons (cytokines) are involved in anti-_____ responses.
Anti-viral
Cells that are infected by a virus produce this type of cytokine.
Interferons
Which type of cytokine tells all surrounding cells to stop dividing, in an effort to stop viral spread/infection?
Interferons
Can viruses undergo mitosis themselves?
No. They can only replicate once they get inside one of our host cells.
Which type of pathogen can only replicate using host somatic cells?
Viruses
Tumour necrosis factor is a cytokine protein that promotes the accumulation of which 2 types of white blood cell?
Neutrophils and macrophages
In which line of defence would you find interferons and interleukins?
The second line of defence (these are both cytokines - protein chemical messengers)
Anti-viral proteins (cytokines) are called _____.
Interferons
Which WBC’s carry out phagocytosis?
Phagocytes
What is the name of the process whereby we engulf and digest cells / microbes?
Phagocytosis
Name 2 types of phagocytes.
Neutrophils
Macrophages
Which type of phagocytic cell is always first on the scene?
Neutrophils
Macrophages are found in ________, whereas monocytes are found in ________ (they are the same thing, other than location).
Macrophages = tissue Monocytes = blood
Monocytes travel in the blood, and when they arrive at a tissue they transform into _______
Macrophages
Phagocytes are non-selective in their targets. What does this mean?
They attack and engulf anything with a foreign antigen.
What do phagocytes use to break down foreign cells?
Lysozomes (balls of digestive enzymes)
Macrophages are antigen presenting cells. True or false?
True
Macrophages present parts of foreign cells they’ve digested to __ - ________.
T-lymphocytes
Name 2 types of antigen presenting white blood cells.
- Macrophages
2. B-lymphocytes
Which WBC’s do macrophages and B-lymphocytes present antigens from broken down foreign cells to?
T-lymphocytes
Macrophages are known as either _______ macrophages, or ______ macrophages.
Wandering or fixed
What is the difference between wandering and fixed macrophages?
Wandering macrophages are monocytes that have migrated in the blood to a site of infection and enlarged in the tissue.
Fixed macrophages stand guard in specific tissues and do not migrate.
Give 3 examples of where you would find fixed macrophages.
- Kupffer cells in the liver
- Alveolar macrophages in the lungs
- Microglia in the central nervous system
Explain the process of phagocytosis in 5 steps.
> Chemotaxis (attracts phagocytes to the area).
Adherence of phagocyte to target
Ingestion of the microbe
Digestion of the microbe, via lysosomes
Excretion of indigestible material
Phagocytosis occurs in ___ stages.
5 stages
What is chemotaxis?
Chemical attraction.
The release of chemicals by microbes, leukocytes, damaged tissue and activated complement proteins.
Name a bacteria that is resistant to the adherence part of phagocytosis, and therefore cannot be digested as normal.
Tuberculosis
A macrophage is an ______ presenting cell.
Antigen
Which non-specific lymphocytes account for just 5 - 10% of lymphocytes?
Natural killer cells
List 4 places that natural killer cells are found.
- Blood (predominantly)
- Lymph nodes
- Spleen
- Bone Marrow
Natural Killer Cells (NKC) attack anything they do not recognise. Name one type of abnormal body cell (not foreign cell) that they may attack.
Cancerous cells
Cancerous body cells will display abnormal surface antigens. True or false?
True
Natural Killer (NK) cells bind to a target cell and release _______ containing the protein ‘______’.
Granules, containing perforin
How does perforin cause cytolysis in a foreign or abnormal body cell?
Perforin inserts into the cell membrane and creates a channel for tissue fluid to flow into the cell. This causes the cell to rupture.
List the 5 cardinal (typical) signs of inflammation.
1. Redness 2, Heat 3. Pain 4. Swelling 5. Loss of function
Mast cells release _______ and _______
Histamine and heparin
_______ is the key chemical in inflammation and is created by the de-granulation of Mast cells.
Histamine
Describe the 3 basic stages of inflammation.
- VASODILATION (increased blood flow)
- Increased vascular permeability (allows arrival of immune cells, antibodies and clotting factors)
- Redness, swelling and heat
- EMIGRATION OF PHAGOCYTES (via chemotaxis) - neutrophils and monocytes
- TISSUE REPAIR
How many clotting factors are there?
13
Which cells release histamine?
Mast cells and basophils
Which chemical mediator, involved in inflammation, causes vasodilation and increased permeability?
Histamine
List 4 inflammatory mediators
- Histamine
- Leukotrienes
- Kinins
- Prostaglandins
Leukotrienes (inflammatory mediator) are produced by ________ and ____ _____
Basophils and Mast cells
What do leukotrienes do?
Attract phagocytes and increase blood vessel permeability, as part of the inflammatory response.
What are kinins?
Proteins that induce vasodilation, increase vessel permeability and attract phagocytes, as part of the inflammatory response.
Which type of chemical mediator involved in the inflammatory response induces pain (and therefore create a pain response)?
Kinins
_________ are lipids released by damaged cells. They enhance the effects of histamines and kinins, and intensify pain.
Prostaglandins
Which chemical mediator involved in the inflammatory response intensifies pain?
Prostaglandins
Prostaglandins are lipids released from cells when those cells are ______.
Damaged
Prostaglandins are made from the ______ ______ _____ part of damaged cell membranes.
Fatty acid tails
List 4 benefits of inflammation.
- Promotes phagocytosis
- Promotes immune response
- Dilutes toxins
- Fibrin formation (helps to isolate a wound and stop infection spreading)
List 4 harmful effects of inflammation.
- Pain
- Swelling (esp. dangerous in the cranium)
- Adhesions and scar tissue
- Atherosclerosis
How does fibrin formation contribute towards a healthy immune system?
Fibrin helps to clot and isolate a wound, which helps to stop infection spreading further.
Atherosclerosis is a harmful effect of ___________
Inflammation
What is a granuloma?
A multi-cellular attempt to contain a foreign body/pathogen by encasing i, if it can’t be broken down and removed.
What is fibrosis?
Scar tissue formation
Does scar tissue have any function?
No
What is a fever?
An abnormally high body temperature.
The release of which chemical mediator from macrophages, causes the hypothalamus to trigger a fever?
Interleukin-1
Name a fever-causing cytokine.
Interleukin-1
Which cells release the fever-causing cytokine, Interleukin-1?
Macrophages
List 3 ways in which a fever enhances immune response.
- It makes interferons more effective
- It inhibits the growth of some microbes
- It speeds up the reactions that aid repair
Many ________ toxins elevate body temperature.
Bacterial
A fever is a natural, beneficial response to an immune challenge and therefore, shouldn’t be suppressed. However, there is a temperature point at which a fever becomes harmful. What is this temperature?
39.5 degrees and beyond
Becomes harmful to proteins and starts to denature and change the shape of them .
State 2 possible outcomes of acute inflammation.
- Resolution
2. Chronic inflammation
What is the function of Interleukin-1? Is it a cell or a protein?
Interleukin-1 induces a fever.
It is a protein (a cytokine)
Explain the role of interferons.
Interferons are anti-viral proteins. They stop surrounding cells from replicating the viral DNA. They are released by the virus-infected cell.
Virus-infected cells release cytokines called ________ which send a message to all surrounding cells, telling them not to replicate (therefore reducing the chances of the viral DNA replicating).
Interferons
What type of cells are either granular or granular?
Leukocytes (WBC’s)
List 3 granulocytes
- Basophils/Mast cells
- Neutrophils
- Eosinophils
Which type of cell is the most abundant WBC in the blood, accounting for up to 60% of leukocytes?
Neutrophils
__________ are first on the scene in an immune response and are phagocytic.
Neutrophils
What is the difference between basophils and mast cells?
They are the same, except basophils are in the blood and mast cells are in the tissues.
Name 2 inflammatory cells / cells that create inflammation.
Basophils and mast cells
Name 2 inflammatory cells that release histamine and heparin.
Basophils and mast cells
Histamine creates ________ and _______ vessel permeability.
Vasodilation and increased vessel permeability
________ is an anticoagulant, released by basophils and mast cells. So in the inflammatory response it ensures an easy flow of fluid / stops stagnation.
Heparin
Mast cells have receptors for Ig___
IgE (immunoglobulin E)
____ is the antibody protein implicated in allergic responses.
IgE
Name a natural anti-histamine.
Quercetin
Which type of WBC destroys parasitic worms via phagocytosis and is also the predominant cell found raised in asthmatic reactions?
Eosinophils
List 3 agranulocytes.
- Monocytes & macrophages
- Natural Killer Cells
- B & T-lymphocytes
What is the difference between monocytes and macrophages?
They are the same, but monocytes are circulating in the blood whilst macrophages (wandering/fixed) are found in tissues.
_______ and _______ are phagocytic and secrete cytokines such as interleukin-1 (fever) and tumour necrosis factor (TNF).
Monocytes and macrophages
Which type of leukocyte targets foreign cells and secretes perforin to induce cytolysis.
Natural Killer Cells
Which 2 leukocytes are involved in the 3rd line of defence?
B and T-lymphocytes
Which 2 leukocytes are involved in ‘specific immunity’?
B and T-lymphocytes
In which line of defence do we create immunological memory?
The 3rd line of defence
In which body system do lymphocytes live?
In the lymphatic system
Where are lymphocytes developed/formed?
In the red bone marrow
Where do B-lymphocytes mature?
In the red bone marrow
Where do T-lymphocytes mature?
In the thymus
Name the 4 types of T-lymphocytes
- Cytotoxic T-Cells
- Helper T-Cells
- Memory T-Cells
- Regulatory T-Cells
Which type of T-lymphocytes are the most active in terms of going out and destroying particular foreign cells?
Cytotoxic T-cells
Which type of T-lymphocyte mediates the immune response?
Helper T-Cells
When are memory T-cells created?
When we have an active exposure to a disease
Which type of T-cells turn off an immune reaction when the immune response should be finished (stopping excessive immune reactions)?
Regulatory T-cells
What do B-lymphocytes produce?
Plasma cells
Which cells produce antibodies?
Plasma cells (produced by B-lymphocytes)
Every single type of plasma cell will create one type of antibody. True or false?
True
___-lymphocytes attack and regulate the immune response. ____-lymphocytes produce plasma cells, which produce antibodies.
T-lymphocytes attack & regulate
B-lymphocytes produce antibodies (via plasma cells)
Which cells, involved in the 3rd line of defence, function in specific immunity (they learn to respond to specific foreign antigens)
T and B-lymphocytes
Which cells produce immune memory for previously encountered antigens?
T and B-lymphocytes
_______ present antigens from foreign particles they’ve digested to ______ _______ cells, who then releases their own cytokines to mediate the body’s response.
Macrophages (or B-cells) present antigens to T-Helper cells, who then coordinate the response.
T and B-lymphocytes are normally at rest but become activated on encountering a foreign antigen. True or false?
True
Which are the effector cells of the ‘adaptive’ immune system?
T and B-lymphoctes
What is the Major Histocompatibility Complex (MHC)?
A group of cell surface proteins that are required for the immune system to recognise cells that are healthy body cells, versus cells that are ‘non-self’.
What is the name given to the group of cell surface proteins that are required for the immune system to recognise cells that are healthy body cells, versus cells that are ‘non-self’?
The Major Histocompatibility Complex (MHC)
What are the names of the 2 types of Major Histocompatibility Complex (MHC) proteins?
- Class 1 Major Histocompatibility Complex (MHC-I)
- Class 2 Major Histocompatibility Complex (MHC-II)
How many types of MHC are there?
Two:
- Class 1 Major Histocompatibility Complex (MHC-I)
- Class 2 Major Histocompatibility Complex (MHC-II)
Which molecules function to present foreign antigens to T-cells?
MHC’s (Class i and II)
MHC’s are each formed of 4 ________ ______and display a _____ produced by the cell (a self antigen) on its binding ______
4 polypeptide chains
Display a protein
Binding groove
Which body cells have MHC-1 (which is effectively your self antigens)?
All body cells except erythrocytes
Erythrocytes are the only cells in the body that don’t have ________
Class 1 Major Histocompatibility Complex (MHC-I)
When might a body cell start to produce abnormal proteins?
When it is cancerous, or invaded by a pathogen.
Abnormal proteins produced by a cell are combined with _______ and displayed on the cell membrane, flagging it up as a non-self cell to leukocytes.
MHC-1
What allows our leukocytes to determine healthy body cells from abnormal/infected cells?
MHC-1, which combines with abnormal proteins produced by the cell and displays them on the cell membrane for the attention of leukocytes.
MHC-1 is essentially a transmembrane protein. True or false?
True
Which is the only body cell that doesn’t create its own proteins?
Erythrocytes
DNA Transcription happens in the _______. Translation happens in the ________ of the cell.
Transcription = nucleus Translation = ribosomes
Whereabouts on the MHC-I and MHC-II is the cell protein/antigen attached/displayed?
In the binding groove.
Which are the only cells to have MHC-II?
The antigen presenting cells (macrophages and B-lymphocytes)
Macrophages and B-lymphocytes at the the only cells that have MHC-II. True or false?
True
What is the role of MHC-II?
To display whatever that particular cell (macrophage or B-lymphocyte) has broken down.
What is displayed on the binding groove of MHC-II?
Parts of digested foreign pathogens (antigen presentation)
What displays foreign antigens to T-helper cells, on its binding groove
MHC-II on the cell membranes of macrophages and B-lymphocytes
Why are MHC-II’s critical in the process of antigen presentation?
Because they are used to display the foreign antigen digested by macrophages/B-lymphocytes to the T-helper cells.
Which cells play a central role in cell-mediated immunity?
T-lymphocytes (T-cells)
Which cells play a central role in antibody-mediated immunity?
B-lymphocytes (B-cells)
__ cells create plasma cells. Plasma cells release _______
B-cells create plasma cells
Plasma cells release antibodies
Which cells are produced in the bone marrow and matured in the thymus?
T-lymphocytes
T-cells are divided into T-Helper cells and _______ T-cells
Cytotoxic
What is unique about all T-lymphocytes?
They each have a unique T-cell receptor, that only recognises a particular antigen.
At what point in life has the thymus atrophied?
By mid-teenage years
Why are T-helper cells also known as CD4 cells?
Because they express the CD4 receptor protein on their surface.
Which 2 immune cells express the CD4 receptor protein on their surface?
T-helper cells & macrophages
What are CD8 cells also known as?
Cytotoxic T-cells
Why are Cytotoxic T-cells also known as CD8 cells?
Because they express the CD8 receptor protein on their surface.
What 2 traits must T-cells have, in order to function properly?
- Self recognition - the ability to recognise self antigens
2. Self tolerance - the lack of reactivity to self antigens
If T-cells lack self tolerance (non-reactivity to self antigens), what medical condition can arise as a result?
Autoimmunity
A loss of T-cell self tolerance leads to ________
Autoimmunity
T-cells are ‘tested’ in the thymus (T-cell school!). Where are B-cells tested?
In the bone marrow
What causes autoimmunity?
Lack of self-tolerance in T-cells
Define adaptive immunity.
Adaptive immunity is the ability of the body to defend itself against specific agents.
How many types of adaptive immunity are there?
2
Name the 2 types of adaptive immunity.
- Cell mediated immunity (T-cells)
2. Antibody mediated immunity (B-cells)
Adaptive immunity is characterised by which 2 things?
- Specificity (for particular foreign antigens)
2. Production of immune memory
Which type of T-cell actively goes out and attacks foreign cells (like Natural Killer Cells)?
Cytotoxic T-cells
What is the difference in the action of Natural Killer Cells and Cytotoxic T-cells?
Natural Killer Cells attack anything foreign
Cytotoxic T-cells attack specific foreign cells
Which of the 2 types of adaptive immunity defends mostly against intra-cellular pathogens?
Cell mediated immunity (T-Cells)
Which of the 2 types of adaptive immunity defends mostly against extra-cellular pathogens?
Antibody mediated immunity (B-cells)
Antigen presentation involves communication between the macrophage / B - lymphocyte and the ___ ______ cells
T-helper
When an antigen fragment binds with a T-helper cell, the T-helper cell secretes a cytokine called ________,
Interleukin II
Which cytokine, released by T-helper cells:
a) is the prime trigger for T-cell proliferation
b) stimulates clonal selection of B-cells
Interleukin II
Which type of T-cell uses perforin and granzymes to attack foreign cells?
Cytotoxic T-cells
Which type of T-cell releases cytokines (including Interleukin II) to increase the activity of immune cells such a T, B and Natural Killer cells?
T-Helper cells
Which type of T-cell recognises an antigen with any future contact, ready to mount an immune reaction when needed?
Memory T-cells
What do Regulatory T-cells do?
Switch off the immune response when it is no longer required.
How do Regulatory T-cells switch off an immune response?
By deactivating immune cells (T-helper cells, macrophages and B-cells)
What would happen if we didn’t have regulatory T-cells?
The body would continue trying to fight off a disease that no longer exists (and would eventually end up fighting its own cells).
Which cells regulate and prevent excessive immune reactions/responses?
Regulatory T-cells.
When regulatory T-cells fail to work properly, what can often result?
Autoimmune conditions
B-lymphocytes form and mature in the _____ ______ and are fixed in ________ tissue where they do not leave.
Bone marrow
Lymphoid tissue
In antibody mediated immunity, __________ cells recognise the antigen on the B-cell membrane and release the cytokine _________, which triggers B-cell clonal selection.
T-helper cells
Interleukin II
Which cytokine triggers B-cell clonal selection in antibody mediated immunity, and which cells is it released by?
Interleukin II. Released by T-helper cells
Which 2 types of cell are produced in B-cell clonal selection?
- Plasma cells
2. Memory B cells
Which type of cell is short-lived and a few days after antigen exposure, secretes hundreds of millions of antibodies into the blood each day until they die?
Plasma cells
Which type of B-cells are long-lived and remember specific antigens for next time?
Memory B-cells.
What are antibodies?
Glycoproteins (part sugar/carbohydrate, part protein). Also known as Immunoglobulins
What is another name for Immunoglobulins?
Antibodies
How many antigen binding sites do antibodies generally have?
2 (Y-shaped)
What type of glycoprotein has a Y-appearance and is made up of 4 polypeptide chains?
Antibodies / Immunoglobulins
How many polypeptide chains do antibodies contain?
4 (2 x heavy and 2 x light chains)
Antibodies bind specifically with the antigen that stimulated their production (“lock and key”). True or false?
True
List 5 ways in which antibodies can inactivate antigens.
- Immobilisation: by latching on to bacterial cilia or flagella
- Agglutination: using their binding sites to clump foreign bodies together.
- Neutralising: Binding to bacterial toxins
- Activating complement: Antigen-antibody complexes activate the compliment cascade.
- Enhancing phagocytosis: Flagging to phagocytes
What is the most abundant antibody in our bodies (c80%) and what does it do?
IgG. Protects us against bacteria and viruses.
Where is IgG mostly found?
In the blood. (Also some in the lymph and intestines)
Which antibody can cross the placental barrier?
IgG
Where is IgA found and what is its function?
IgA is found in sweat, tears, saliva and breast milk. It gives localised protection of mucous membranes.
Which antibody is very closely linked to stress levels (i.e, is lowered/depleted when a person is stressed)
IgA
Which type of antibody is the first on scene in an immune response, normally then followed by IgG?
IgM
Which antibody type accounts for <1% of the antibodies in the blood and is involved in allergic reactions?
IgE
Which antibody type causes mast cells to release histamine and heparin?
IgE
A true food allergy involves ____ antibodies, whilst a food intolerance will typically involve an _____ antibody response.
Food allergy = IgE
Food intolerance - IgG
How long can memory cells last?
Decades
Why is a second exposure to a particular antigen/bacteria/virus much more effective when it comes to antibody production?
Because the first exposure = a slow rise in IgM then IgG (takes a few days for the body to get on it).
Subsequent exposure is a much faster response because the immune system has already developed thousands of memory cells from the last attack. Often the secondary response is so effective that it kills off the microbe before you exhibit any signs or symptoms.
What is the basis for vaccination against certain diseases?
Immunological memory
Why do vaccines contains lots of ingredients in addition to the partially live/dead foreign microbe?
- To keep the microbe in tact/alive until injected.
- To make sure the microbe doesn’t get broken down
- To create an immune response against the pathogen
Why are toxic heavy metals often added to vaccines?
To ensure the creation of an immune response when the vaccine is injected.
List 4 harmful ingredients often found in vaccines.
- Aluminium (to create immune response)
- Formaldehyde (vaccine preservative)
- Polysorbate 80 (to allow heavy metals through the blood-brain barrier)
- Mercury (to create immune response)
List 3 ways in which we can acquire immunity.
- Natural exposure to a disease
- Transfer of IgG antibodies across the placenta
- Transfer of IgA antibodies in breast milk
- Vaccination
- Injection with immunoglobulins (ie, anti-snake venom)
Give an example of naturally acquired active immunity.
Natural expose to a disease
Give an example of naturally acquired passive immunity.
- Transfer of IgG antibodies across the placenta
- Transfer of IgA antibodies in breast milk
Give an example of artificially acquired active immunity.
Vaccination
Give an example of artificially acquired passive immunity.
Injection with immunoglobulins (i.e, anti snake venom)
What is the difference between active and passive immunity?
Active immunity - your body works to produce an immune response & antibodies
Passive immunity - the immune response / antibodies are delivered into the body, so it doesn’t need to do anything itself to create them.
How many main types of antibody are there?
4 - IgM, IgG, IgA, IgE
Which types of immune cells are found in GALT (Gut Associated Lymphoid Tissue)?
Macrophages, B & T-lymphocytes
Which layer of tissue within the wall of the gut contains GALT?
The lamina propria (2nd layer)
Why is the gut microbiome important in immune health?
Because leukocytes learn from the microflora in the gut.
Define hypersensitivity.
An excessive immune response produced by the immune system.
Hypersensitivity is divided into ____ types.
4
Which hypersensitivity types are antibody mediated?
Types I, II and III
Which type of hypersensitivity is cell mediated?
Type 4
Which type of T-cells are involved in hypersensitivity Type 4?
Cytotoxic T-cells
What is another name for a Type I Hypersensitivity?
An allergy
Which type of hypersensitivity is immediate/rapid in its response and mediated by IgE antibodies?
Type I hypersensitivity (allergy)
What is anaphylaxis?
A big immune response (Type I hypersensitivity)
List 3 pathologies associated with localised Type I hypersensitivity (antibody mediated) reactions
- Hayfever
- Eczema
- Some contact dermatitis
What type of (antibody mediated) hypersensitivity reactions are involved when we get blood transfusion reactions?
Type II hypersensitivity
Give an example of a Type II hypersensitivity (antibody mediated) pathology
Haemolytic Disease of the Newborn
rhesus negative mother, rhesus positive baby
Which type of antibody is involved in all Type II hypersensitivity responses?
IgG
List 3 pathologies associated with Type III hypersensitivity immune reactions
- Glomerulonephritis
- SLE (lupus)
- Rheumatoid arthritis
Antibody-antigen complexes activate the ________ system.
Complement system
Type ____ hypersensitivity is IgA, IgG and IgM mediated.
Type III hypersensitivity
Why is the deposition of antibody-antigen complexes common in the glomerulus?
Because the blood pressure in the glomeruli is so high (4x higher than the systemic circulation)
Which type of hypersensitivity is associated with an over-reaction of cytotoxic T-cells to an antigen?
Type IV (4) hypersensitivity
Name 2 pathologies associated with Type IV hypersensitivity.
- Multiple Sclerosis
- Skin graft rejection
What is an allergen?
An antigen that generates allergy (a type I hypersensitivity reaction)
Give 4 examples of common allergens
- Dust mites
- Animal dander
- Dust
- Latex
- Pollen
- Certain foods
IgE cross-links _____ cells with an antigen, causing degranulation.
Mast cells
IgE antibodies grab the allergen on one of their Y arms and a mast cell with the other Y arm, linking them and causing the mast cell response.
Give an example of a common food intolerance and explain the cause.
Lactose intolerance.
Caused by a lack of the enzyme lactase, which is needed to properly digest lactose.
What is anaphylactic shock?
A very sudden, severe, systemic allergic response, within 5-10 minutes of antigen exposure.
Why is anaphylactic shock so dangerous?
Because it causes bronchoconstriction and vasodilation, which results in blocked airways.
How is anaphylactic shock treated?
By epi-pen (adrenaline)
What are autoimmune disorders?
Conditions associated with an immune response against the body’s own tissues.
Define autoimmunity.
A breakdown of mechanisms responsible for self tolerance.
There are significant links between autoimmunity and _____ gut.
Leaky gut
What can zonulin be used for?
A biomarker for increased intestinal permeability (leaky gut).
Which chronic, multi system autoimmune disease follows a relapsing-remitting course and involves antibodies that directly focus on targeting the nucleus and components of the offending cell’s DNA?
Systemic Lupus Erythematosus (SLE)
What is unique about the action of IgG antibodies in Lupus (SLE?)
They directly target components of cell nuclei (DNA, nucleic acids, etc)
Which autoimmune pathology would you be looking to diagnose if you test for Anti-nuclear antibodies in the blood?
Systemic Lupus Erythematosus (SLE)
Lupus is a multi-factorial disease, involving genetics, hormones and environmental factors. True or false?
True
List 5 potential causes of Systemic Lupus Erythematosus (SLE).
- Oestrogen dominance
- Low vitamin D levels
- Chronic bacterial infections
- EBV
- Smoking & silica dust
Patients with SLE usually suffer from significant sensitivity to sunlight, so are often told to apply factor 50 suncream. Why is this a bad thing?
Because it means that they are most likely vitamin D deficient and D3 deficiency is a cause / risk factor for SLE.
List 3 things that can cause flare-ups in patients with SLE.
- Contraceptive pill use
- HRT
- UV light
- Stress
- Pesticides
List 5 signs/symptoms of lupus (SLE).
- General fatigue and malaise
- Butterfly rash on the face
- Photosensitivity
- Joint pain
- Vasculitis (pain in fingertips)
- Raynaud’s Syndrome
- Pleurisy
- Nephrotic syndrome
- Pericarditis
- Anaemia
What is the allopathic treatment for lupus (SLE)?
- Immunosuppressants
- Corticosteroids
- High factor sun cream
- NSAIDs
Which chronic, systemic autoimmune disease primarily attacks the synovium (potentially all organs except the brain)?
Rheumatoid Arthritis
Which genes are implicated in Rheumatoid Arthritis?
HLA-DR4 and DR1
Which auto-antibody is present in around 80% of RA sufferers?
Rheumatoid Factor (RF)
________ _________ is an antibody that attacks other antibodies (IgG) in the blood, causing immune complexes that deposit in synovial joints and other tissues.
Rheumatoid Factor
List 5 signs/symptoms of RA.
- Symmetrical/bilateral arthritis of small joints (mostly hands and feet)
- Progressive morning stiffness, lasting >1hr
- Deformity of joints (swan neck, ulnar deviation)
- General fatigue and malaise
- Subcutaneous nodules
Which systemic autoimmune disease is associated with chronic inflammation of the spine and sacroiliac joints?
Ankylosing Spondylitis (AS)
Ankylosing Spondylitis more commonly effects _____ between the age of 15 - ____ years of age.
Males
Between 15 - 30yrs
Which gene is present in 95% of patients with Ankylosing Spondylitis (AS)?
HLA-B27
Which autoimmune disease has been linked to inflammatory bowel diseases (and leaky gut), as well as urogenital or intestinal infections such as Salmonella & Shigella?
Ankylosing Spondylitis (AS)
List 4 signs/symptoms of AS.
- Pain & stiffness in the lower back, ascending.
- Kyphotic posture
- Worsening morning stiffness
- Fatigue and malaise
- 20% suffer acute iritis
In which autoimmune disease would you find raised CRP/ESR, the HLA-B27 gene and potentially a ‘bamboo spine’ on X-ray/MRI?
Ankylosing Spondylitis (AS)
Which autoimmune disease occurs when antibodies start reacting with thyroglobulin proteins and/or thyroid cells?
Hashimotos Thyroiditis
In which autoimmune disease might you see an absence of knee reflexes?
Hashimotos Thyroiditis
In which autoimmune disease might you see goitre and exophthalmos?
Graves Disease
In which autoimmune condition do we see IgG antibodies binding to TSH receptors, stimulating production of thyroid hormones?
Graves Disease
What is the allopathic treatment for Graves Disease?
Carbimazole (drug)
Radioactive iodine
Explain the role of Interleukin-II
Interleukin-II is a cytokine that causes clonal selection (the creation of T-helper cells, cytotoxic T-cells, memory T-cells, plasma cells and Memory B-cells)
Briefly describe the structure of an antibody.
A Y-shaped structure that has 4 polypeptide chains, a constant and variable region and 2 binding sites.
What is the most abundant antibody found in the blood?
IgG
Give an example of naturally acquired passive immunity.
Transfer of IgA antibodies through breast milk.
Transfer of IgG antibodies through the placenta
Where does self-recognition and self-tolerance of T-cells develop?
In the thymus (where they mature)
