Morphology of central nervous system disease in immunosuppressed mice after peripheral herpes simplex virus...

Inoculation of mice and rabbits on the cornea with herpes simplex type 1 virus has been shown to cause an ascending infection of the trigeminal nerve, ganglion, and descending tract within the brainstem (2, 3, 7). A discrete, destructive, and primarily demyelinative lesion is seen on the central nervous system side of the trigeminal root entry zone 5 to 8 days after infection (8, 15, 16). This study, utilizing Swiss mice, demonstrated that immunosuppression with cyclophosphamide prior to infection with herpes simplex type virus causes a marked reduction of the mononuclear infiltrate within the central nervous system and a significant decrease in myelin destruction when compared with the infected, nonimmunosuppressed control animals. The content of virus in the brainstem was similar in both groups by day 8 as were the neutralizing antibody titers to herpes simplex type 1 virus. These results suggest that the cellular response plays a definitive role in the destruction of central nervous system tissue after peripheral infection with herpes simplex type 1 virus.