Medical Uses of Monoclonal Antibodies (WJEC GCSE Biology)

Diagnosis of disease

Immunoassays are used in the diagnosis of diseases caused by Chlamydia trachmatis, HIV, and Plasmodium:

Radioactively labelled monoclonal antibodies are added to test samples of infected body fluids. These attach to specific antigens on the disease-causing cells. The extent of the infection is related to the extent molecules detected by the labelled monoclonal antibodies

Tissue typing for transplants

The concentration of non-self-antigens in tissues can be assessed:

 B-lymphocytes within transplant tissue would normally cause rejection as these would be detected as non-self antigens by the body's immune system. These are prevented from functioning by monoclonal antibodies that can be used against the body's T-lymphocytes (Helper T-cells) which would attack the non-self B lymphocytes

Monitoring the spread of malaria

Blood samples are taken from individuals (even if they do not show any malarial symptoms) and tested with labelled monoclonal antibodies:

The presence of the Plasmodium parasite in the bloodstream can be detected by monoclonal antibodies, even if the parasites are dead having been killed by anti-malarial drugs. Specific antigens from Plasmodium will attach to labelled monoclonal antibodies. Labelled monoclonal antibodies can be detected and their quantity measured, indicating the presence of malaria. This enables the success of anti-malarial drugs and the potential spread of malaria to be monitored.

Destruction of cancer cells

The destruction of cancer cells can be targeted with the use of monoclonal antibodies:

Tumour markers are a special type of antigen found on some cancer cells. Monoclonal antibodies can be produced that act specifically against tumour marker antigens. The monoclonal antibodies can be attached to anti-cancer drugs so that the drug will be delivered directly to the cancer cells and thereby destroying them.