An immunohistological study on the nephritis in chicks experimentally produced with avian nephritis virus

One chick inoculated by a combined nasal and conjunctival sac route (in) and two chicks inoculated per os (io) died with visceral urate deposits at post inoculation days (dpi) 9 and 11. All infected chicks showed renal degeneration and inflammatory changes that originated from tubular cell necrosis. Avian nephritis virus (ANV) antigen was detected as cytoplasmic granules within the necrotic tubular epithelial cells. The serum uric acid was increased in in- and io-infected chicks 5 to 10 dpi and was coincident with the severity of the renal degeneration. Immunoglobulin (IgG and IgM)-containing cells were detected first in the renal lesion 5 and 7 dpi; they were coincident with the cell infiltration. IgG- and IgM-containing cells were demonstrated in the spleen 5 dpi and increased thereafter eight to 12 times more than those in non-infected control chicks. They were almost coincident with the detection of antibody against ANV. These findings suggested that ANV replication may stimulate the proliferative response of IgG- and IgM-containing cells in the spleen, and that the appearance of IgG- and IgM-containing cells in the kidney may also be closely associated with the clearance of ANV and regeneration of the renal lesion.