Dendritic cells help the body to switch on an immune response by seeking out foreign proteins (antigens) and showing them to the T and B cells. They are normally present all over the body but only in very small numbers, which means that they are difficult to isolate and study. At the British Society for Immunology Annual Congress in Brighton this week, Dr Jonathan Austyn of the University of Oxford will explain how recent advances have made it possible to grow large numbers of dendritic cells in the lab, opening the way to their use in the treatment of cancer.
Cancers may develop because the immune system is not given a strong enough signal to destroy the tumour. There is even evidence that, in some cases, cancers are able to turn off the immune response. For example, immature dendritic cells are found in some cancers. However, substances produced by the tumour prevent the cells from developing into a more mature form which can stimulate an immune response. These substances may even cause the death of the dendritic cells.
However, immunologists now think it should be possible to over-ride the effects of these substances. Dendritic cells can be separated from the patient's blood or bone marrow and grown in large quantities in culture. They can then be shown bits of the tumour to which the immune system will react (tumour antigens) and reinfused into the patient. A recent clinical trial using this approach in the United States was most encouraging.
In certain types of cancer, such as the skin cancer malignant melanoma, it is known that patients can mount an immune response to the developing tumour. However, in many cases this response ultimately fails. Could treating patients with beefed-up dendritic cells help to maintain this response?
Dr Austyn and his colleagues will be starting a Phase I clinical trial early in
1998 where they will use dendritic cells to try to treat patients with advanced
(Stage IV) malignant melanoma or breast canc
Contact: Dr Jonathan Austyn
+44 1 865 221 281
British Society For Immunology