Chronic serum sickness in the rat: influence of antigen dose, route of antigen administration and strain of rat on the development of disease.

Chronic serum sickness (CSS) with systemic immune complex deposition has been produced in female Fischer (F344) rats by the daily intravenous (i.v.) administration of 2.0 mg bovine serum albumin (BSA) (Arisz et al., 1979). In the experiments described below, daily i.v. doses ranging from 0.5 to 10.0 mg BSA were found to be effective in producing CSS in F344 strain rats. The severity of renal disease and the extent of extrarenal immune complex deposition were increased with higher daily doses of BSA. Daily administration of different doses of BSA by an intraperitoneal (i.p.) route resulted only in slight mesangial glomerular abnormalities and did not cause abnormal elevation of urinary protein excretion. At the same time, extrarenal accumulation of immune deposits similar to that observed in rats given BSA by the i.v. route was seen. Wistar and Lewis (LEW) strain rats were similar to F344 strain rats in susceptibility to the induction of CSS, but daily i.v. injection of 2.0 mg BSA failed to produce the disease in Brown Norway (BN) rats. The latter observation suggests that genetic differences may influence the expression of immune complex disease in this model.