5. Cell recognition and the immune system Flashcards
What are monoclonal antibodies?
Antibodies produced from a single group of genetically identical b-cells (plasma cells) specific to one type of antigen.
Why are all monoclonal antibodies identical in structure?
They have the same primary structure as they are all coded for by the same gene.
As a result they also have the same secondary and tertiary structure.
How are monoclonal antibodies produced?
The specific antigen binds to the receptor of the b-cells.
A helper t-cell sends out a chemical signal to activate the b-cell.
This releases specific antibodies.
Some plasma cells, mean identical antibodies will be produced
Why can monoclonal antibodies be used in the creation of ‘targeting drugs’?
They all have the same unique tertiary structure.
This means that they will then bind to a specific antigen with a complementary shape.
Therefore, you can make monoclonal antibodies bind to a specific target molecule, such as a cell antigen.
How can monoclonal antibodies be used in the treatment of cancer?
Individual types of body cells have a different type of surface antigen that can be identified.
Cancer cells carry a unique antigen called a tumour marker.
Monoclonal antibodies can be produced to bind to these tumour markers. Anti-cancer drugs can then be attached to these antibodies.
Thus the drugs will only be released where antibody binding occurs, only affecting cancer cells.
This reduces side effects because the drugs will only accumulate at specific cell sites.
How can monoclonal antibodies be used in pregnancy testing?
The placenta in a pregnant woman produces the hormone HCG, this can be found in the mother’s urine.
Monoclonal antibodies are immobilised in coloured beads on a test strip.
When urine is applied, any HCG will bind to the antibodies to form antigen-antibody complexes.
The HCG-antibody-colour complex moves along the strip until it is trapped by a different type of antibody.
The creation of this specific complex accumulates to produce a coloured line confirming pregnancy.
What are the ethical issues surrounding the production and use of monoclonal antibodies?
Production requires the use of mice to produce the antibodies, in order to produce them the mice must have tumour cells present in the body.
The mice must be injected with cancer cells.
Pros and cons of the use of monoclonal antibodies in humans?
Pro: Positive results in treating cancer and diabetes.
Con: Negative results involve deaths in treating multiple sclerosis. - In 2006 a drug trial involved the injecting of monoclonal antibodies into patients suffering with multiple sclerosis. Within minutes 6 participants went into multiple organ failure.
on a basic level, how does a virus replicate?
Virus attaches to host cell and injects its genetic material
The genetic material is used as a code to synthesise proteins in the nucleus
New virus particles are assembled
Viruses burst out of and destroy the host cell
what two regular functions of cells can viruses not perform?
respire
photosynthesise
explain the function of a attachment protein when looking at viruses
allows the virus to attach to the host cell
explain the purpose of DNA/RNA when looking at viruses
proteins that encode for the virus
explain the purpose of a capsid when looking at viruses
protein coat that encapsulates the DNA/RNA
explain the purpose of nucleoproteins when looking at viruses
accessory protein e.g enzymes
true/false
viruses are not formed of cells
viruses are considered non-living
true
true
what is HIV?
Human Immunodeficiency Virus
interferes with the functioning of the immune system.
why is HIV called a retrovirus?
because it uses the enzyme reverse transcriptase to perform reverse transcription
what is AIDS?
a disease of the immune system, HIV kills or interferes with normal functioning of the immune system, leading to AIDS
However not always a result of HIV
how can you test for HIV?
ELISA testing.
enzyme linked immunosorbent assay
how does an ELISA test work?
It uses antibodies to detect the presence of certain proteins (antigens) , CD4
why do antibodies not work against viral diseases?
viruses have no metabolic processes or cell structures for antibiotics to disrupt.
a virus protein coat means that antibiotics can not bind to sites.
How does HIV replicate?
through the use of helper T-cells
the attachment proteins on the virus are complementary to the proteins on the surface of T-helper cells
Explain some advantages of ELISA testing
very sensitive so can detect the smallest amounts of protein.
can also be used to detect hepatitis and tuberculosis, not just HIV
can also be used to detect the amount of drugs in a person’s system
Explain why AIDS is deadly to sufferers?
AIDS sufferers have around 200mm-3 T-helper cells circulating opposed to the healthy 1000mm-3
sufferers develop small infections a lot easier and faster. complications of infections are also far more likely to be deadly
Usually HIV/AIDS does not kill a person, the ill health associated with it does
