Protection of newborn mice against herpes simplex virus infection by prenatal and postnatal transmission of antibody.

Pre- and postnatally acquired protection against herpes simplex virus type 2(HSV-2) infection mediated by maternal antibody was investigated in the newborn mouse. Newborn mice, 2 days old, were inoculated with HSV-2 intraperitoneally after maternal immunization with live or inactivated virus. The survival rates improved in proportion to the maternal neutralizing antibody titres. Ninety-three percent of animals delivered by Caesarean section from immune mothers and suckled by non-immune mothers survived viral infection, whereas 7% of control animals survived. The same was true with animals born to non-immune mothers and nursed by immune mothers. In foetal sera and milk of immunized mice, anti-HSV activity was associated primarily with antibody of the IgG class as measured by enzyme-linked immunosorbent assay (ELISA). In addition, oral administration of antibody conferred protection on newborn mice. These studies indicate that maternal IgG, acquired not only postnatally but also prenatally, plays an important role in protecting newborn mice against HSV infection.