The ejection of antigens from cancer cells is strictly regulated. This has now been proven by scientists at Universitätsklinikum Erlangen, FAU. A better understanding of this mechanism could help in the development of new strategies to improve tumour recognition, as reported by the scientists in an article in ‘Journal of Clinical Investigation’.
Tumours use a variety of strategies to avoid being recognised directly by the body’s immune system. As special protein complexes are not usually attached to the cell surface, the immune system is not able to recognise tumour cells directly.
An exception to this is the indirect recognition of tumour cells. Tumour antigens are released as a result of uncontrolled cell death initiated by the rapid growth of tumours, or radiation therapy or chemotherapy. These can then be taken up by special immune cells, known as antigen-presenting cells. These special immune cells are then in a position to present the released proteins from the tumour cells to the body’s own immune system, triggering a renewed immune response. Up until now, however, very little research has been conducted into whether the release of such antigens is strictly regulated or whether it is simply an uncontrolled consequence of cell death.
Dr. Sascha Kretschmann from the Chair of Haematology and Oncology has now been able to demonstrate for the first time that a certain chaperone protein in the cell promotes a selective rejection from the tumour cell. This hinges on a certain amino acid sequence, which must be coded in the antigen itself.