Identification of salivary proteins inhibiting herpes simplex virus 1 replication

Salivary proteins play an important role in the maintenance of the oral ecology. Previous studies have indicated that human submandibular‐sublingual and parotid salivas can selectively suppress the in vitro infectivity of herpes simplex virus 1. The purpose of this study was to identify the salivary components in human submandibular‐sublingual saliva that modulate in vitro infectivity. Assessment of the interaction of viral particles with salivary components was accomplished using an in vitro solid‐phase assay. These experiments revealed that herpes simplex virus particles selectively interact with the members of the salivary proline‐rich protein and cystatin families. Subsequent yield reduction assays demonstrated the ability of proline‐rich proteins and salivary cystatins to inhibit the viral replication, with basic proline‐rich peptides being more effective. Subsequent assays suggest that basic proline‐rich peptides reduced the virus titer by interfering with penetration and/or cellular processing of virus within the target cell. Collectively, these results further suggest that salivary proteins have an important role in the host defense mechanism against recurrent herpesvirus infection.