[Immune complex disease of Swan and nude mice]

Swan and Nude mice with antinuclear antibodies (AN Ab) show early deposits of Ig and C in the mesangium and the basement membrane of glomerulus, marking an immune complexes disease. We have studied the Ig class of these immune complexes after acid elution and by direct immunofluorescence with suitable conjugates. In the Swan mice, fixed Ig are chiefly IgM and IgA, but AN Ab in the eluate kidney are principally IgG2 and IgM as the circulating AN Ab. In these mice the Ag of the fixed immun complexes are AN and murine leukemia virus Ag. In the Nude mice, fixed Ab are IgM and IgG2 and in part AN Ab. The circulating AN Ab and the AN Ab of eluates are also IgM and IgG2.