'T cell versus T cell': A Study of the Cellular Immune Response in Cutaneous T cell Lymphoma (CTCL)

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Cutaneous T cell lymphomas (CTCL) are a group of malignant disorders derived from T lymphocytes, a type of white cell within our immune system. These malignant T cells settle mainly within the skin and cause severe complications. The rate at which the disease progresses within individual patients is variable but no genetic or phenotypic abnormalities of the tumour cell have been identified which determine disease progression. An alternative suggestion is that it is the patients' immune response to the tumour which regulates the aggressiveness of the disease. There is currently a great deal of interest in how our immune system may act to prevent or control cancer. Indeed, many patients with diseases such as lung cancer are now achieving long term remission after injection of molecules called antibodies that boost the strength of the immune system. Interestingly, these drugs are believed to act by increasing the activity of T cells - the very cell that is the cause of cancer in patients with CTCL. Evidence shows there is a cancer-specific immune response in patients with CTCL and in this fellowship we propose to investigate this in detail, in order to guide the introduction of new immune-based therapies. One fascinating aspect of the proposal is that we will examine how normal T cells are potentially able to control growth of malignant T cells. This will provide very novel information about the potential role of immune-modulatory therapy in patients with CTCL, which will be applicable to the treatment of cancer in general.In order to carry out this work we will recruit patients from one of the largest CTCL clinical units in Europe, and blood and skin biopsies will be taken at different stages of disease. Malignant and reactive T cells will be isolated and examined by multi-parameter flow cytometry, including a complete analysis of co-stimulatory molecule expression. We will use antibody probes to determine the pattern of expression, on both malignant and normal T cells, of the molecules that can suppress normal immune function. One exciting aspect here is that we will have access to a new technology, CtTOF, which will allow us to determine the presence of up to 34 proteins on the surface of cells at the same time. We will also try to find molecules within the malignant T cells that act as the targets for the immune response. We will focus on cancer testis antigens (CTAg), a remarkable family of proteins that normally only expressed in germ cells such as testis or ovary, but which are also expressed in many cancers. Using reagents called tetramers we will investigate the presence of CTAg-reactive T cells and assess why they are not effective in patients with progressive disease. Finally we will culture healthy T cells isolated from within CTCL biopsies with the CTCL cancer cells themselves, to see if they can recognise and kill the tumour cells. We will then use investigate how we can block inhibitory signalling molecules to investigate how we can strengthen killing of the cancer.We believe that we are strongly placed to perform this work as we bring together one of the largest and most academically active CTCL clinical units within the UK together with a very strong research team within tumour immunology. We anticipate that the results will contribute to a substantial increase in understanding of the mechanisms of immune evasion by CTCL. This research programme will have direct relevance to the study of tumour immunology both within CTCL and in relation to other forms of cancer. The beneficiaries of the work will therefore include academics working within tumour immunology and a wide range of cancer physicians. Most importantly, we believe that it can be used to guide the introduction of immune-stimulatory antibody therapy through a personalised approach in patients with CTCL.