Immunologic aspects of facial nerve paralysis induced by herpes simplex virus infection in mice

The immunologic aspects of facial nerve paralysis due to herpes simplex virus type 1 (HSV-1) infection were investigated in a mouse model system. Half of the 4- to 5 week-old mice developed facial nerve paralysis, whereas none of the 6-week-old mice died or developed facial nerve paralysis on inoculation with HSV-1. Six-week-old mice showed significantly higher titers of anti-HSV-1 neutralizing antibody than did 4-week-old animals. Passive transfer of either anti-HSV-1 antibody or HSV-1-immunized splenic T cells into 4-week-old mice 3 hours after HSV-1 inoculation prevented development of facial nerve paralysis and death, whereas such transfers 48 or 96 hours after HSV-1 inoculation did not prevent or exacerbate facial nerve paralysis. These results demonstrate that the age and the immunologic potency of mice are closely related to the pathogenesis of facial nerve paralysis. That facial nerve paralysis developed even in 6-week-old mice whose T-cell function was suppressed with anti-CD3 antibody suggests that virus-induced cellular demyelination is unlikely as a cause of facial nerve paralysis in this animal model.