Terminal Deoxynucleotidyl Transferase - Uses

Uses

Terminal transferase has applications in molecular biology. It can be used in RACE to add nucleotides which can then be used as a template for a primer in subsequent PCR. It can also be used to add nucleotides labeled with radioactive isotopes, for example in the TUNEL assay (Terminal deoxynucleotidyl transferase dUTP Nick End Labeling) for the demonstration of apoptosis (which is marked, in part, by fragmented DNA). Also used in the immunofluorescence assay for the diagnosis of acute lymphoblastic leukemia.

In immunohistochemistry, antibodies to TdT can be used to demonstrate the presence of immature T and B cells and multipotent haematopoietic stem cells, which possess the antigen, while mature lymphoid cells are always TdT-negative. While TdT-positive cells are found in small numbers in healthy lymph nodes and tonsils, the malignant cells of acute lymphoblastic leukaemia are also TdT positive, and the antibody can therefore be used as part of a panel to diagnose this disease and to distinguish it from, for example, small cell tumours of childhood.