The Human Immunodeficiency Virus 2 Flashcards
Which cells does HIV specifically attack?
Helper T cells
How does HIV cause AIDs?
HIV kills or interferes with the normal functioning of helper T cells, weakening the immune system
Why is the loss of helper T cells harmful to the immune system?
It prevents the activation of B cells, which produce antibodies then cytotoxic T cells which kill infected cells
How does HIV affect memory cells?
Memory B cells may also be infected and destroyed, further weakening immune responses
Why do people with AIDs become more susceptible to infections and cancers?
The immune system cannot produce an adequate response, making them vulnerable to secondary infections
What are common secondary infections in AIDs sufferers?
Lungs, intestine, brain and eye infections along with weight loss and diarrhoea
Does HIV directly cause death?
No, the death is caused by secondary infections that the weakened immune system cannot fight
What is the purpose of the ELISA test?
To detect the presence and quantity of a specific protein (etc. an antigen) in a sample
Why is the ELISA test highly effective?
It is extremely sensitive and can detect very small amounts of a molecule
How does the ELISA test work?
1) Apply the sample to a surface (slide) so all antigens in the sample attach
2) Wash the surface several times to remove any unattached antigens
3) Add the antibody specific to the antigen that is being detected, leaving both to bind together
4) Wash the surface to remove excess antibody
5) Add a second antibody that binds to the first antibody. This second antibody has an enzyme attached to it
6) Add the colourless substrate of the enzyme, the enzyme acts on the substrate to change it into a coloured product
7) The amount of the antigen present is relative to the intensity of colour that develops
What is the first step in the ELISA test?
Apply the sample to a surface (for example a slide) so that all antigen attach
Why is the surface washed after applying the sample?
To remove any unattached antigens, ensuring only specific binding occurs
What is added after washing the surface?
A specific antibody that binds to the antigen being tested for
Why is the surface washed again after adding the specific antibody?
To remove any excess unbound antibody
What is the role of the second antibody in the ELISA test?
It binds to the first antibody and has an enzyme attached to it
What happens when the colourless substrate is added?
The enzyme converts it into a coloured product, indicating the presence of the antigen
How is the quantity of antigen determined in ELISA?
The intensity of the colour is proportional to the amount of antigen present
Why is ELISA useful in drug testing?
It measures drug quantity, which is important since some drugs occur naturally in low concentrations
