Glomerulonephritis in the owl monkey (Aotus trivirgatus): ultrastructural observations.

: The kidneys of 11 clinically healthy owl monkeys (Aotus trivirgatus) acquired from four different sources were examined by light and electron microscopy. Eight of the 11 animals had morphologic evidence of glomerulonephritis. The lesions were characterized by one or more of the following changes: focal or segmental thickening of the glomerular basement membrane; proliferation of mesangial cells with increased production of mesangial matrix; and fibrosis and hyalinization of glomeruli with and without inflammatory cellular infiltration. Five of the eight animals with one or more of the above described changes had electron-dense deposits compatible with immune complex deposits in the intra-membranous and subepithelial regions of the basement membrane. The nature and source of the antigen or antigens responsible for the lesions are unknown.