Detection of Islest Cell Surface Antibodies (ICSA) Using a Human Pancreatic B-cell Clone

Abstract

A human pancreatic B-cell clone (JHPI-1) was used as a target of islet cell surface antibodies (ICSA) in comparison with rat and/or mouse islet cells by indirect immunofluorescence and ¹²⁵Iprotein A binding assay. ICSA was detected in the sera of patients with insuline-dependent diabetes mellitus (IDDM) and normal healthy controls. All the sera that were positive for ICSA against rat and/or mouse islet cells were also positive for ICSA against JHPI-1 cells as expected, while in healthy normal controls all the sera that were negative for ICSA against rat and/or mouse islet cells were also negative for anti JHPI-1 cell ICSA. The percentage of positively stained living JHPI-1 cells correlated with that of living rat islet cells (r=0.81, p<0.01). Conversely, some IDDM pa, -tients sera that were negative for ICSA against rat and/or mouse islet cells reacted with JHPI-1 cells. Furthermore, the binding of ¹²⁵I-protein A to JHPI-1 cells exposed to sera from IDDM patients correlated with the binding to rat and/or i slet cells, and the ability of JHPI-1 cells to bind ¹²⁵I wasgreater than that of the rat and/or mouse islet cells.
In conclusion, it was possible to use not only rat and mouse islet cells, but also a human pancreatic B-cell clone derived from human fetal pancreas as target cells in these assays. Our data also indicate that JHPI-1 cells express relatively species-specific antigens on their surfaces and that there might be human-specific ICSA against human islet cells in the sera of IDDM patients.