Increased risk of experimental central nervous system listeriosis in rats with chronic serum sickness. An immunohistopathological study.

The incidence and severity of central nervous system (CNS) infection were increased following the intraperitoneal innoculation of Listeria monocytogenes in adult Wistar rats with experimental chronic serum sickness. The results were attributed to an alteration in the blood-cerebrospinal fluid barrier induced by immune complex deposits in the choroid plexus of animals hyperimmunized with bovine serum albumin. CNS inflammation occurred in 16 of 40 (40%) of the test animals studied; one of 36 (2.8%) controls had CNS inflammation. There were extensive pathological changes in the choroid plexus, subarachnoid space, and neural parenchyma of the test animals, as compared with only small inflammatory foci limited to the choroid plexus and subarachnoid space in the one affected control. This experimental model for inducing bacterial CNS infection simulates certain predisposing conditions in chronic immune disease, and may therefore be useful in studying the pathogenesis of CNS infection in such cases.