Islet cell antibodies in Sulawesi macaques

Older monkeys of the Sulawesian species Macaca nigra spontaneously develop a lesion in the pancreatic islets of Langerhans in which there is depositio n of amyloid and gradual degeneration of all cells, which can lead eventual ly to development of diabetes mellitus. Islet cell antibodies (ICA), formed in response to the release of cellular antigens, can be used to detect the islet lesion and to monitor the progression of each monkey toward diabetes . Numerous M. nigra and one M. tonkeana in captivity have been tested, but it is unknown whether the islet lesion occurs in monkeys in their natural h abitat of Sulawesi. Blood samples collected from M. maurus, M. tonkeana, an d hybrid M, maurus/tonkeana were assayed for ICA, When all monkeys were con sidered together, 33% had ICA positive against beta cells and 14% had ICA p ositive against alpha and/or D cells. Appearance of ICA in blood of males w as virtually the same as in females. These results are similar to those fou nd in M. nigra examined in captivity. Since all Sulawesian species share a common genetic heritage, these results would support the appearance of this lesion in their natural habitat. Cause(s) for formation of the lesion and eventual development of diabetes are unknown. There may be genetic factors or genetic predisposition to environmental factors. If environmental factor s are responsible, then they must be present not only in the wild, but eith er carried with the monkeys or universally available, since M. nigra born i n captivity also develop the lesion and diabetes after physical maturity at ca, 7+ years. Am. J. Primatol. 47:223-229, 1999. (C) 1999 Wiley-Liss, Inc.