NERVE GROWTH-FACTOR ANTIBODY STIMULATES REACTIVATION OF OCULAR HERPES-SIMPLEX VIRUS TYPE-1 IN LATENTLY INFECTED-RABBITS

Anti-nerve growth factor (anti-NGF) antibody has been shown to induce reactivation of latent herpes simplex virus type 1 (HSV-1) in vitro. W e found that systemically administered anti-NGF induces ocular sheddin g of HSV-1 in vivo in rabbits harboring latent virus. Rabbits in which HSV-1 latency had been established were given intravenous injections of goat anti-NGF serum daily for 10 days beginning 42 days after prima ry viral infection. Tears were assayed for virus for 12 days beginning on the day of the first injection. All eight rabbits given high titer anti-NGF had infectious virus in their tears at least once during the 12-day period. Fifteen of 16 eyes were positive and the average durat ion of viral shedding for these eyes was 4.0 days. Latently infected r abbits receiving daily injections of nonimmune goat serum or saline fo r 10 consecutive days were controls. Only six of the 16 (38%) eyes fro m rabbits receiving nonimmune goat serum shed virus. Only one of 12 ey es from untreated rabbits shed virus. Sera from control rabbits had no detectable anti-NGF activity; titers in anti-NGF-treated rabbits rang ed between 1:1000 and 1:10 000. NGF deprivation may act as a neuronal stressor and may share a common second messenger pathway with heat- or cold-stress induced reactivation of latent HSV-1.