The Thomsen-Friedenreich (TF) receptor: an old history with new mystery.

The Thomsen-Friedenreich (TF) receptor represents the cryptic precursor structure of the human MN blood group system. Blood group antigens, however, are no longer regarded to be restricted to red cells because most of them are carbohydrate markers. Therefore, these anti-blood group antibodies, especially blood group specific lectins, can be widely used to detect different carbohydrate units of numerous glycoconjugates in several organs. Blood group antigens of carbohydrate character and their precursors seem to be important signals during malignant transformation of normal cells, as they can be altered in different ways within the architecture of the cancer cell membrane. In this connection, the significance of the TF receptor is presented, as well as its position among other and different anti-galactose specific reagents (in the broadest sense) from various sources. The biological role of these lectins and lectin analogues is discussed and a purification method is recommended.