Palmerston North mice, a new animal model of systemic lupus erythematosus

This report describes a previously unrecognized animal model of SLE, the PN mouse. Although outbred PN mice were studied originally as models of polyarteritis nodosa, their inbred descendants have autoimmune disease which closely resembles SLE. In the current study, positive indirect immunofluorescence tests for ANA appeared when the mice were 5 months old, and 80% of mice were ANA-positive at 10 months of age. Anti-DNA were detected in sera from newborn mice and from 53% of mice under 2 months of age. Seventy-six percent of PN mice developed anti-DNA at the age of 10 months. Glomerular deposits of IgG, IgM, IgA, and complement appeared at 2 to 4 weeks of age, and examination of renal tissue by electron microscopy showed basement membrane thickening and dense intramembranous deposits. Neoplasms arose in 14% of PN mice. Female mice died earlier than male mice, and the most common causes of death were glomerulonephritis and arteritis. It was concluded that the serologic and histologic characteristics of disease in PN mice resembled SLE.