T lymphocyte participation in acute serum sickness glomerulonephritis in rabbits

The extent and timing of glomerular T lymphocyte infiltration was studied in acute serum sickness (AcSS) glomerulonephritis (GN) in rabbits. AcSS was initiated by a single intravenous injection of bovine serum albumin (BSA). Rabbits developed circulating BSA anti-BSA immune complexes, and rapid immune elimination of the circulating antigen was associated with the deposition of immune complexes in the kidney and the onset of a diffuse endocapillary proliferative GN. On the day of immune elimination (defined as when less than 1% of the injected antigen remained in the circulation), rabbits developed significant proteinuria (98 +/- 36 mg/24 h; normal 14 +/- 1 mg/24 h, P less than 0.01), glomerular macrophage accumulation (44.3 +/- 21.1 macrophages per glomerulus [mac/glom]; normal 0.28 +/- 0.18 mac/glom, P less than 0.01), and a significant glomerular T lymphocyte influx (3.0 +/- 0.9 cells/glomerular cross-section [c/gcs]; normal 0.47 +/- 0.13 c/gcs; P less than 0.005). On the day prior to immune elimination, increased T cells numbers were observed in some rabbits (2.4 +/- 2.1 c/gcs) together with a minor macrophage presence (7.6 +/- 3.6 mac/glom) and minimal proteinuria (17.6 +/- 3 mg/24 h). These studies demonstrate the influx of T lymphocytes together with macrophages at the onset of proteinuria in serum sickness nephritis and are consistent with a role for cell-mediated immunity in the pathogenesis of this lesion.