Characteristic immunohistochemical and ultrastructural glomerular lesions in Nude mice.

Kidney glomerular lesions were studied by light microscopy and immunofluorescence in 17 congenitally athymic Nude mice and 25 of their phenotypically normal littermates. The 3-month-old mice had glomerular deposits of total IgG, IgG2, IgM, and C3, but IgG1 was consistently absent and IgA was present in only 30 per cent of cases. Conversely, the 6-month-old littermates showed no deposits. However, the 9- and 12-month-old littermates had glomerular deposits of all of the immunoglobulins and C3. Kidney tissue from five Nude mice was studied by electron microscopy. In three of these five mice the mesangial and subendothelial deposits contained characteristic double layered lamellar structures approximately 130 A wide. Antinuclear antibodies were found in the serum of 3 or 10 Nude mice and 1 of 12 littermates. Different hypotheses on the origin of the characteristic lamellar structures are proposed. The significance of the early development of autoimmunity and glomerular lesions in Nude mice is discussed.