Turnover and transformation of T cell clones in retroviral infection and leukaemia

Human T lymphotropic virus -1 (HTLV-1) is a retrovirus which causes an aggressive blood cancer, adult T cell leukaemia/lymphoma (ATL), in 5% of carriers. HTLV-1 preferentially infects CD4+ T cells, and the virus genome is found inserted into the DNA of malignant cells in ATL. We know that individuals who poorly control the virus have a particularly high risk of developing cancer, and that the viral burden is principally controlled by the cytotoxic T lymphocyte (CTL) response to HTLV-1. Here I will describe some novel approaches we have developed (1) to assess the efficiency of CTL killing of HTLV-1-infected and leukaemic T cells ex vivo and (2) to quantify and characterise clonally expanded HTLV-1-infected malignant T cells.