Immunity Flashcards
(48 cards)
What is a monoclonal antibody
Antibodies that have the same tertiary structure and are produced by cloning of plasma cells (B-cells)
2 examples of using monoclonal antibodies in medical treatments:
Cancer treatment -> antibodies are injected into blood, and they bind to specific cancer cell’s antigens and block it from reproducing
–> diagnosing disease, pregnancy test,
–>medical diagnosis/ cancer testing
–>passive immunity vaccines.
Describe the role of antibodies in producing a positive result in an ELISA test?
1st antibody binds/attaches to complementary antigen shapes that are bound to test plate.
2nd antibody with an enzyme attached is added to the test plate and attaches to this antigen ( the 1st antibody-antigen complex formed in step 1)
The solution/substrate is added and will change colour once it has binded with the enzyme attached.
Why was the amount of antibody given to the mice calculated in g per kg of body mass. Explain why the dose was calculated per unit mass?
To take into account the different masses of mice.
Explain how antibodies are produced when the mice were injected with sheep red blood cells?
Sheep red blood cells have antigens on their surface, which activate B-cells with specific complementary receptors, causing them to differentiate into plasma cells and produce antibodies.
Explain why, in a test strip test, which is using monoclonal antibodies to detect disease, the antibodies only bind to specific antigens.
Antibody found in blood/sample in the test is only complementary to the binding site shape of the antigen found on the test plate.
Explain why it is important to have a control line in a test strip, which is using monoclonal antibodies to detect a disease.
Prevents a false negative result because the antibody found in the blood sample had moved up the test strip and has not bound to any other antigens on the test strip that would indicate a positive test.
How would you join the points on a plotted graph?
Straight lines point to point as it would be impossible to predict the intermediate values between the points
Describe the role of macrophages in stimulating B lymphocytes.
Is an antigen in membrane presented to B lymphocytes
Or
produces cytokinins
Explain how antigenic variability causes some people to become infected more than once with influenza viruses?
Memory B-cells do not recognise new antigens, and so the antibodies shape that is previously produced is no longer complementary to the new antigen.
Describe how bacteria are destroyed by phagocytosis
Bacterial pathogen releases chemicals that attract phagocyte towards it.
Phagocyte engulfs pathogen and forms phagosome.
Lysosomes bind to phagosome and release contents into it, enzymes/lysozymes
That digest/hydrolise the bacteria.
An antigen in a vaccine leads to the production of antibodies. Describe the part played by B- lymphocytes in this process?
Phagocyte presents antigens to B lymphocytes.
Antigen binds to the complementary receptors on the B-lymphocytes
Lymphocytes become activated and cause themselves (B-lymphocytes) to reproduce by mitosis and undergo clonal selection
Forms plasma cells that secrete the antibodies into blood and memory cells.
Describe how giving a HPV vaccine leads to the production of antibodies against HPV?
Vaccine contains antigen from HPV
They are displayed on antigen presenting cells
Specific T-helper cells detect antigen and stimulate B-cells to divide by mitosis and clone to give plasma cells
Plasma cells produce antibodies that have specific complementary binding sites to the HPV antigen and these are secreted into the blood.
How does a vaccine work?
Vaccine contains antigen from sed disease e.g.. HPV virus
Displayed on antigen presenting cells
specific T-helper cells detect antigen and stimulate B-cells to divide by mitosis and clone to form Plasma cells and memory cells
Plasma cells produce antibodies with specific complementary binding sites to the antigen of the sed disease cell e.g. a bacterial cell, HPV virus.
Give 3 ways a doctor could use base sequences to compare different types of one virus e.g.. HPV virus type 1, 2 and 3
Compare base sequences of DNA
Look for mutations
Compare base sequences of mRNA
Main components of HIV are:
Capsid,
Phospholipid membrane (bilayer),
Why might a person with HIV develop a large number of infections about 9 years after he became infected with HIV?
HIV virus remains dormant and it only exists as DNA in host DNA
HIV destroys T-cells in body
So more free viruses are produced and this leads to fall in number of T-cells
Fewer T-cells can activate B-cells to divide by mitosis to form memory cells and plasma cells therefore antibody production is reduced
immune system not working properly cos has inability to fight infections
How does a DNA virus work?
The attachment protein of the DNA virus binds to the receptor on a human cell this binding allows DNA to enter the cell.
DNA is injected into the cell and joins the DNA in the nucleus of the cell.
The virus DNA is turned into messenger RNA (mRNA), so the ribosomes make more viruses which eventually burst out the cell because there are so many and they will go out and spread and bind to more human cells due to having the same receptors.
This forms a DNA viral disease.
What is reverse transcriptase used for in HIV RNA?
To turn HIV RNA into HIV DNA
How do RNA VIRUSES work?
E.g. HIV
The attachment protein of the RNA binds to the receptor only found on the T helper cells. The RNA is injected into the T helper cells. Alongside the RNA reverse transcriptase is (and enzyme) is injected. This enzyme makes DNA from RNA, using the DNA nucleotide from the host cell. (Cell the virus is infecting). This DNA is single stranded and is called complementary DNA. The virus uses DNA polymerase and more DNA nucleotides to form the second strand of DNA to make it double stranded so that it can join to the host cells DNA in the nucleus
Bacterial pathogens
Release toxins and divide
Viral pathogens
Replicate inside cells
HIV to aids process
When you are HIV positive you have the HIV virus in your body and it will only be in the T helper cells. It will lie dormant and then suddenly start to replicate after a while. It then attacks lots of T helper cells. The person will get aids because without the T helper cells they cannot fight off all the infectious diseases that the body normally fights.
How can HIV be thwarted into forming AIDS?
Aids can be thwarted by using antiviral drugs these drugs stop viruses replicating and therefore prevent HIV developing into AIDS however they have horrible side effects so most patients end up stopping using the drugs and end up with aids.
