Processes are provided for the synthesis of the human T-antigenic determinant 2-acetamido-2-deoxy-3-O-(.beta.-D-galactopyranosyl)-.alpha.-D-galactopyran oside containing an .alpha.-O-glycosidically linked bridging arm O--(CH.sub.2).sub.n COR. The determinant is coupled to carrier molecules to form artificial T-antigens, and to insoluble supports to form T-immunoadsorbents. The artifical T-antigen is shown to elicit a delayed type hypersensitivity reaction as a diagnostic for the presence of cancer in humans.