3.2.2 Uses of Monoclonal Antibodies

What is hCG and where is it found?

hCG (human chorionic gonadotrophin) is a hormone present in the urine of pregnant women.

How do pregnancy tests use monoclonal antibodies?

The first section contains mobile antibodies complementary to hCG, attached to blue beads. The second section contains stationary antibodies complementary to hCG, stuck down to the stick. If hCG is present, it binds to the mobile antibodies, forming hCG/antibody complexes that bind to stationary antibodies, producing a blue line.

How are monoclonal antibodies used in laboratories?

They are used to measure and monitor levels of hormones or chemicals in the blood. Monoclonal antibodies are modified to bind to specific molecules and can be linked to fluorescent dyes so they can be detected (e.g. screening donated blood for HIV).

How are monoclonal antibodies used in research?

They are used to identify certain molecules on a cell or tissue. If the molecules are present, the fluorescently bound antibodies show up, indicating the molecule's presence.

How are monoclonal antibodies used in treating cancer?

Cancer cells have tumour markers not found on normal cells. a) Monoclonal antibodies can bind to tumour markers to stimulate the immune system to attack the cell. b) They can bind to receptor sites, blocking growth signals and stopping the cells from dividing. c) They can carry toxic drugs, chemicals, or radioactive substances directly to cancer cells.

What are the advantages of using monoclonal antibodies?

They only bind to specific cells, so healthy cells are not affected. They can be engineered to treat many different conditions. Mouse-human hybrid cells reduce the risk of triggering an immune response.

What are the disadvantages of using monoclonal antibodies?

It is difficult to attach monoclonal antibodies to drugs. They are expensive to develop. Since they originate from mice, they can sometimes trigger immune responses in humans.