Influence of antigen charge in the pathogenicity of immune complexes in rats.

Immune complexes (IC) formed in the presence of excess antigen with native human anionic (AA) or cationic (CA) albumin and anti-human albumin rabbit gamma globulin were administered to 51 female Wistar rats. In animals injected with IC formed with CA, IC deposition in the renal glomeruli (glomerular capillary walls and mesangium) occurred as early as 5 min after injection. These animals also showed slight alterations in renal structure and albuminuria, whereas in the animals injected with IC formed with AA there was no IC deposition in the renal glomeruli nor any alteration in renal structure or albuminuria. The serum complement levels of animals injected with IC formed with CA were significantly lower than those observed in animals treated with similar doses of IC formed with AA. In vitro experiments also showed that the IC formed with CA fixed more complement than those formed with AA.