Islet cell surface antibodies in type 1 (insulin-dependent) diabetes mellitus: use of human fetal pancreas cultures as substrate.

Sixteen pancreases from 11-24 week old human fetuses were cultured for up to 11 days to investigate islet cell surface antibodies. Hormonal content and presence of cytoplasmic autoantigen were assessed by immunofluorescence with specific antihormone sera and high titre cytoplasmic islet cell antibody positive sera. Viable islet cells cultured on coverslips were tested with 21 islet cell antibody positive sera from Type 1 (insulin-dependent) diabetics, one islet cell antibody positive serum from a non-diabetic and four normal control sera. Surface binding immunoglobulins were detected by indirect immunofluorescence in nine out of 11 newly diagnosed Type 1 diabetics and in two out of ten longstanding diabetics with another coexistent autoimmune endocrinopathy. The four-layer double immunofluorescence technique showed that the surface antibody stained insulin secreting cells, but owing to rarity of A and D cells in the fetal cultures it has not yet been possible to exclude the reactivity of islet cell surface antibodies with glucagon or somatostatin cells.