Anti-Blood Group A1B Antigen Anticorps [HE-24] (A86814)

Blood group antigen expression in human colon cancer was studied by means of two monoclonal antibodies of broad anti-A (HE-14) and anti-type 3 and type 4 chain-based A and H (HE-10) specificity. These antigens were proved to reappear in tumors of the distal colon, the HE-10 antibody reacting more frequently (9 out of 12 samples) than HE-14 (5 out of 12 samples) and frequently with supranuclear staining of the cytoplasm probably in those places of the Golgi apparatus where carbohydrate antigens are synthesized. This staining pattern is characteristic of HE-10 in normal colonic mucosa as well. With HE-14, staining was often absent in less differentiated tumors, while HE-10 did react in such tumors. In this connection, the possible expression of type 3 and type 4 chain H antigens in the tumor tissue is discussed. In some cases, these two antibodies gave different staining patterns in parallel sections from the same tissue sample, primarily at the cellular level. Three out of 12 cases showed blood group antigen expression in the mucosa of the distal colon adjacent to the tumor only when HE-10 antibody was used.

Six different hybridoma cell lines were obtained producing IgM monoclonal antibodies (MAbs) against human blood group A antigen. All these MAbs agglutinate the A1, A1B and A2 erythrocytes, while only one of them agglutinates the A2B erythrocytes. The agglutination activity of 3 of these MAbs is inhibited by N-acetyl-D-galactosamine (D-GalNAc). Dissociation constants of complexes of these MAbs with D-GalNAc are approximately 2.2 X 10(-3) mol/l.