Intra-ocular and CNS listeriosis following systemic infection in Wistar rats with chronic serum sickness.

The relationship of immune complex deposits and cell-mediated immunity to the occurrence of ocular and brain listeriosis following a low (0.007-0.03 LD50) intraperitoneal challenge was investigated in 68 Wistar rats with chronic experimental serum sickness and 68 normally resistant controls. The induction of chronic serum sickness involved long continued immunization with bovine serum albumin which resulted in a high level of immune complex entrapment in both the ciliary processes (92%) and choroid plexus (74%) of eye and brain. The extensive immune deposits were associated with a high (23%) incidence of CNS listeriosis and a much lower rate (5.9%) of ocular listeriosis. The difference in incidence could not be related to impaired cell-mediated immunity based on cultural data in liver and spleen. The results seem to indicate that the eye is less vulnerable to systemic listerial infection in chronic immune complex disease despite comparable immune complex entrapment in the ciliary processes and choroid plexus. The findings reflect biologically significant differences between eye and brain that influence their respective vulnerability to systemic Listeria, an opportunistic bacterium, of clinical importance in patients with chronic immunological disorders.