The relative role of transplacental and milk immune transfer in protection against lethal neonatal herpes simplex virus infection in mice.

The role of passive maternal immunity in neonatal herpes simplex virus (HSV) infection is controversial. C57BL/6 mice born to HSV-immune mothers had significantly greater survival than those born to nonimmune mothers after an intraperitoneal or oral HSV challenge. In subsequent experiments with intraperitoneal and oral HSV challenge, non-immune mice that were foster fed for one week by actively or passively immunized mothers were significantly protected. Injections of passive antibody postpartum in nonimmune mother mice resulted in detectable transfer of antibody to HSV to their infant mice via breast milk. In mice, maternal breast milk, not transplacentally derived antibody, protects neonates from low-dose HSV infection.