HETEROGENEITY OF HUMAN ISLET CELL ANTIBODIES IN TERMS OF CROSS-SPECIES REACTIVITY

There has been no consistent view about the cross-species reactivity of islet cell antibodies (ICA), and no report about their target antigens in the pancreatic islet cells of different species. Therefore, we examined the cross-reactivity of human ICA against rodent pancreatic islet cells, and found at least two types of ICA, one having a comparatively strong cross-reactivity and the other lacking it. Furthermore, using human as well as some rodent pancreatic tissues that had been modified chemically, we came to suspect that the target antigens of ICA were sialic acid residues of glycolipids. Therefore, we suggest that there are at least two types of ICA recognizing sialic acid residues of glycolipids, one reacting with antigen(s) commonly present in human and rat islets, and the other with antigen(s) only present in human islets. © 1990.