THOMSEN-FRIEDENREICH-RELATED CARBOHYDRATE ANTIGENS IN NORMAL ADULT HUMAN TISSUES - A SYSTEMATIC AND COMPARATIVE-STUDY

A broad variety of normal human tissues were examined for the expressi on of Thomsen-Friedenreich (TF)-related histo-blood group antigens, TF (Gal beta 1-3GalNAc alpha 1-R), Tn (TF precursor, GalNAc alpha 1-R), sialosyl-Tn (NeuAc alpha 2-6GalNAc alpha 1-R), considered to be useful in cancer diagnosis and immunotherapy, and sialosyl-TF, the cryptic f orm of TF. These antigens or, more correctly, glycotopes, were determi ned by immunohistochemistry with at least two monoclonal antibodies (m Abs) each (except sialosyl-TF) as well as by lectin histochemistry. Fo r a better dissection of sialosyl-TF and TF glycotopes, tissue section s were pretreated with galactose oxidase or the galactose oxidase-Schi ff sequence. Staining with mAbs appeared to be more restricted than wi th the lectins used. Distribution patterns among normal epithelia were different for all four antigens. These antigens were also detected in some non-epithelial tissues. They can be classified in the following sequence according to the frequency of their occurrence in normal tiss ues: sialosyl-TF >> sialosyl-Tn > Tn > TF. Most of the positively stai ning sites for TF, Tn, and sialosyl-Tn are located in immunologically privileged areas, The com complex results obtained with anti-TF mAbs ( after treatment of the tissue sections with sialidase from Vibrio chol erae) and the lectins amaranthin and jacalin revealed a differential d istribution of the subtypes of sialosyl-TF [NeuAc alpha 2-3Gal beta 1- 3GalNAc alpha 1-R and Gal beta 1-3 (Neu-Ac alpha 2-6)GalNAc alpha 1-R] in normal human tissues. From our data it can be inferred that TF, Tn , and sialosyl-Tn are promising targets for a cancer vaccine.