3) What is ELISA and why is it used?
Not 100% sure on the other ones, so I will leave them for someone else, but for ELISA...
ELISA (Enzyme-Linked Immunosorbent Assay) is a technique that uses an antibody-enzyme complex. The antibody section of the complex binds with the pathogen antigen. The enzyme ‘s usual substrate is then added and reacts with the enzyme, producing a colour change that can be detected.
The process is as follows:
1. Antibodies for the suspected antigen (of the pathogen) are added to the bottom of a well
2. The blocking agent is added to fill any areas not bound by the antibody.
3. Swabs from a patient’s sample are added. If the antigen is present in the sample, it attaches to the antibody. If the antigen is not present in the sample, it does not attach to the antibody.
4. An antibody with an enzyme attached is added. If the antigen has attached to the antibody, this second antibody attaches to the other end of the antigen. If the antigen has not attached, this second antibody does not attach either.
5. The plate is treated is that the solutions in the wells turn a particular colour only in the presence of the antigen-antibody complex.
Note: between each of the above steps, a washing step occurs to remove any loose particles.
The strength of the colour indicates the quantity of antigens present. The darker the colour, the more antigens are present, and therefore the more infectious the person is.
(Sorry... just copied it directly from my notes so hopefully it makes some sense
)
Hi,
Can someone explain how monoclonal antibodies work... is it a form of rational drug design?
Thanks,
Monoclonal antibodies are antibodies that are produced from a single plasma B cell. Basically, the process is:
1. An antigen (for which antibodies are required) is injected into the cell of an animal (e.g. a mouse). The animal produces plasma B cells that are specific to the antigen.
2. The plasma B cells are removed and fused with a tumor cell (called hybridisation) because tumor cells replicate rapidly and uncontrollably, and therefore are very effective to produce high numbers of the plasma cell.
3. The result is called a hybridoma cell, and it is capable of synthesising large amounds of the monoclonal antibody. They can be extracted and used for theraputic purposes, such as diagnostic tests such as pregnancy tests, neutralising toxins in poisons that are produced by endotoxins in the blood, or to target cancer cells if the body does not do this itself.
I am pretty sure that monoclonal antibodies are not a rational drug, but someone else might have to clarify this.
Hope all of this kind of makes sense...sorry if it doesnt!