Blood group related carbohydrate antigens in human fetal pancreas

Many tumor-associated carbohydrate antigens are related to the blood group systems. Since several of these antigens are developmentally regulated, a systematic knowledge of the expression of blood group related carbohydrate antigens during organogenesis is important. By immunohistochemical methods we investigated the expression of carbohydrate structures related to the ABH, Lewis, T and Tn blood group systems in 28 fetal pancreas, from 13th-40th gestational week using a comprehensive set of well-defined monoclonal antibodies, reacting with type 1, 2, 3, and 4 chain carbohydrate structures. The following antigens were found in fetal pancreas: Type 1 chain: Lea, Leb, monosialylated Lea and disialylated Lea, type 2 chain: N-acetyllactosamine (the immediate precursor to blood group H antigen), branched N-acetyllactosamine, H-antigen, Lex and Ley; type 3 chain: H-antigen. The T-antigen was well expressed, whereas this was not the case with the Tn-antigen. As expected the A-antigen was found in 10 of 24 cases. The A-related antigens: ALeb, ALed and ALey were only found in a few of these ten specimens whereas type 3 chain A-repetitive was found in all of them. Since msLea, Lex, Ley and T-antigen have been described as tumor-associated antigens, we conclude that several carbohydrate tumorrelated antigens are expressed in fetal pancreas.