11.1 - antibody production and vaccination Flashcards
1
Q
how does the immune system produce histamines?
A
- White blood cells in connective tissue secrete histamines in response to an infection
- producing cells are: mast cells and basophils
- cells are often called granulocytes and circulate the blood
- when needed cells secrete histamine that makes dilation of small blood vessels in the infected area
- causes blood vessels to leak fluid that contains immune components into the area
- this is an immune response
2
Q
what is the effect of a histamine?
A
- contributes to the symptoms of an allergic reaction, rashes, swelling, anaphylaxis, sneezing ect.
- variety of allergens can cause this reaction: pollen, medication, nuts
- anti-histamines decrease the effects of allergic responses induced by histamines
- Anti-histamines act by blocking the histamine receptors, so limiting the effect on the surrounding tissue and reducing symptoms
3
Q
what do antigens do in the immune system?
A
- triggers an immune response in an organism
- The surface of human cells also contains proteins and polypeptides; these are often referred to as self.
- The immune systems function because they can distinguish between foreign antigens and self
4
Q
what are antigens?
A
- they are foreign to the organism
- they are proteins and large polysaccharides
- found on the surface of cancer cells, parasites and bacteria, as well as on pollen grains and the external surface of viruses
5
Q
how do blood transfusions work with blood antigens?
A
- Blood groups are based on the presence or absence of certain types of antigens on the surface of red blood cells
- if the ABO blood group and the Rhesus (Rh) blood group don’t match with donor and recipient it will create an immune response
- blood transfusions, the transfer of an incompatible blood type results in agglutination followed by hemolysis in the recipient
- This results in the destruction of foreign red blood cells, and this may coagulate in blood vessels.
6
Q
what are pathogens?
A
- cause disease or illness in their hosts
- Most pathogens are specialised and therefore have a narrow range of hosts
- some viruses are specific to birds, pigs, dogs or bacteria
- also bacterial pathogens such as syphilis or viral pathogens that only cause disease in humans
- species-specific bc of specific receptors and and need for optimal temp
7
Q
what are zoonoses?
A
- they are pathogens that can cross species barriers
- like covid 19, Lyme disease, bird and swine flu, West Nile virus, Ebola, salmonellosis
-considered an emerging global health concern and can result in human deaths as there is a lack of immunity in human populations and/or due to a lack of understanding of the pathogen
8
Q
what is the principle of immune response?
A
“challenge and response” has been used to explain how the immune system produces large amounts of specific antibodies needed to fight infections by pathogens
9
Q
how do Antibodies produced by T-cell mediated responses, help the immune system?
A
- Macrophages ingest pathogens by endocytosis
- The phagosome with pathogen fuses with a lysosome and digestive enzymes will break down the pathogens to antigens.
- antigens then placed on membrane proteins called MHC II (Major
Histocompatibility Complex) proteins - then do antigen presentation at the cell surface
- T cells can only be activated by antigen-presenting cells that have processed and presented the antigen
- antigen is presented to T-helper cells which have specific antigen receptors and the T-cell with the matching receptor will bind to the antigen presented by the macrophage
- macrophage will pass a secondary signal to the TH cell that activates it
- T cell will bind to B cell with a B cell receptor specific to the antigen will be activated. Both the TH cell and B cell with be specific to the same antigen.
- B cell is activated by the direct binding and signals sent from the TH cell.
10
Q
what is antigen presentation?
A
- MHC II molecules with antigen transported in vesicles to plasma
membrane where it shows the processed antigen on the macrophage cell surface.
11
Q
what is colonial expansion?
A
- activated B cells will proliferate (by mitosis) to form clones and differentiate cells into either plasma cells or memory B cells
- Majority of the clones become plasma cells, which are mature B cells
12
Q
what are the plasma cells from colonial expansion?
A
- have extensive rough endoplasmic reticulum throughout the cytoplasm, which is needed to synthesise, modify and transport antibodies
- Only the genes for synthesising the specific antibody is upregulated (same as B cell receptor)
- number of plasma cells contract once the infection has resolved
13
Q
memory cells from colonial expansion?
A
- a small number of clones differentiate into memory cells
- Memory cells remain in circulation after the infection is cleared and are inactive until the same antigen (pathogen) infects the body
- Memory cells give long-term immunity to the disease
14
Q
why do plasma cells secrete antibodies?
A
- Antibodies are secreted and help to destroy the pathogen in many different ways
- antibodies in vesicles are transported by exocytosis
- Antibodies only persist for a short period (few weeks to months), and contribute to short-term immunity
15
Q
what is the role of antibodies?
A
- responsible for the destruction of pathogens following the immune response, and antibodies use a number of different ways to clear infection.
16
Q
what is Opsonisation?
A
- where antibodies bind to the antigen or pathogen and make it more recognisable to phagocytes so they are more readily engulfed and broken down.
17
Q
what is the Neutralisation of bacteria and viruses?
A
- where the antibodies bind to the bacteria or virus and prevents it from binding to host cells and thus blocks entry to the host cell.
18
Q
what is the Neutralisation of toxins?
A
- where antibodies bind to the toxins produced by pathogens and prevents it from affecting host cells.
19
Q
what is Activation of complement?
A
- where antibodies will bind to the antigen and recruit a system of proteins called complement
- complement system uses a cascade of proteins to form a membrane attack complex that forms a pore in the membrane of the pathogen, this perforation causes lysis and ultimately the destruction of the pathogen
- complement proteins bound to the antibodies can also act to opsonise pathogens for phagocyte clearance
20
Q
what is Agglutination?
A
- where antibodies that bind to the antigen causes clumping of pathogens, thus reduces pathogen population and prevents pathogens from entering host cells. This also makes it easier for phagocytes to engulf for clearance
21
Q
what is the primary immune response?
A
- Immunity develops when the immune system is challenged by a specific antigen and responds by producing antibodies to fight the infection and memory cells
- first encounter to a specific antigen will result in relatively slow production of antibodies as there are very few B cells with a B cell receptor specific to the antigen
22
Q
what is the secondary immune response?
A
- a second encounter (and all subsequent encounters) to the same antigen, this will result in a much faster and higher concentration (titre) of antibodies due to the presence of memory cells that were produced from the primary response.
- faster and higher titre of antibodies results in a faster clearance of the pathogen, and faster recovery by the individual
23
Q
what is a vaccine?
A
- introduced into the body, typically by infection
- may contain a live attenuated (weakened) version of the pathogen or some derivative of the antigens from the pathogen
- introduction of the antigen will stimulate a primary immune response, where the antigens stimulate the production of antigen-specific antibodies
- vaccination is still classified as active immunity or acquired immunity as the antigen is artificially introduced
24
Q
what does a vaccine do?
A
-first vaccine will cause small concentrations of antibodies to be produced and some memory cells formed
- If the actual antigen enters the body as a result of infection, it will be destroyed by the antibodies in a secondary immune response
- sometimes a second vaccine (or booster shot) may be administered to cause a secondary response
- second encounter with the same antigen results in a response from the memory cells for faster and greater antibody production
25
Q
what did Jenner do?
A
- infected a child with cow pox to show that he wouldnt get small pox
- when he recoverd from cow pox he was given small pox and he had risistance
- although very unethical explained our immune response
- he then made a vaccine basically and eradicated small pox
26
Q
what is Epidemiology?
A
- the study of the distribution patterns and causes of disease in a population.
- spread of the disease, the cause and predictions to minimise outbreaks are all part of epidemiology
27
Q
what do epidemiologists do ?
A
- epidemiologists contribute to planning and evaluating the severity of disease progression in a population, and are also responsible for planning and evaluating vaccination programmes
- Vaccination programmes are effective in minimising harm caused by outbreaks.
- Worldwide initiatives and collaborations for polio and tetanus have been successful in reducing (almost eradicated) disease
28
Q
what are Monoclonal antibodies?
A
- highly specific, purified antibodies that are produced by a clone of cells, derived from a single cell
- they recognise only one antigen
29
Q
how do you produce clone cells to make hybridoma cells?
A
- the antigen is injected into a mouse or another mammal
- This stimulates an immune response where the mammal makes plasma cells that produce antibodies
- various types of plasma cells are removed from the spleen of the mammal
- As only some plasma cells will produce the desired antibody, these plasma cells are selected
- The plasma B cells are fused with cancer cells called myeloma cells to form a hybridoma cell.
30
Q
how are hybridomas used to produce monoclonal antibodies?
A
- many different plasma B cells are fused with myeloma cells, so many different hybridoma cells produced
- Each hybridoma needs to be tested to identify the hybridoma that produces the desired antibody
- then the hybridoma cell is allowed to proliferate (divide) to form clones.
- ## These cells are cultured and will continue to secrete vast quantities of the desired monoclonal antibody
31
Q
what are Monoclonal antibodies used for?
A
- Monoclonal antibodies are used to treat and diagnose diseases including the test for malaria or HIV, and for forming antibodies for passive vaccination in rabies victims
32
Q
how does a pregnancy test use Monoclonal antibodies?
A
- used to detect the presence of human chorionic gonadotrophic (hCG) in urine
- hCG is only produced during pregnancy by the developing embryo and the placenta
- It is present in the urine of pregnant women and can therefore be used to identify pregnancy
