Replication of herpes simplex virus in blood monocytes and placental macrophages from human neonates

Abstract

Increased permissiveness of macrophages for herpes simplex virus (HSV) replication may be a mechanism for the dissemination and severity of neonatal herpetic infection. We have assessed the replication of HSV in neonatal blood monocytes and placental macrophages using several criteria for viral permissiveness. Assay of production of infectious progeny virus indicated that cord blood monocytes, like adult monocytes, were nonper-missive for HSV (about 1% of cells producing virus). In vitro culture of cord blood monocytes resulted in increased replication of HSV, but to no greater extent than virus production in cultured adult cells. HSV infection of fetal placental macrophages was weak but present (4.4% of cells). Assay of production of viral antigens and electron microscopic analysis of structural elements indicated that a larger number of cord blood monocytes and placental macrophages were abortively infected than were productively infected. These results indicate that monocytes and macrophages from human neonates do not show the enhanced permissiveness for HSV demonstrated in newborn mice and suggest that dissemination of herpetic infection in human newborns cannot be explained by increased neonatal monocyte permissiveness for HSV. © 1989 International Pediatric Research Foundation, Inc.