REQUIREMENTS FOR ENTRY OF HERPES SIMPLEX VIRUSES (HSV) INTO PRIMARY HUMAN VAGINAL/CERVICAL CELLS. † 715

Abstract

Genital HSV infection is a major health problem that impacts both on sexually active individuals and neonates who become infected perinatally. To develop new strategies for the prevention of HSV, determination of the requirements for establishment of genital infection is imperative. The aims of these studies are to identify requirements for entry of HSV into cervical cells. Primary cultures were established using fragments of vagina, ectocervix and endocervix from specimens obtained from patients who had undergone hysterectomies for conditions such as endometriosis. Pts. ranged in age from 30-54, mean 43±7 years. We found that both HSV-1 and HSV-2 form plaques on primary cells within 24 h of infection; at the same m.o.i., virus plaques on cell lines in 48-72 h. Endocervix (columnar epithelium) was more susceptible to infection than ectocervix (squamous epithelium). Susceptibility of HSV infection increased if cells were cultured in the presence of 10-8-10-10 m/L of 17-beta-estradiol. We found that heparan sulfate serves as a receptor for binding of HSV to the cells. Heparin, an analog of HS, but not other glycosaminoglycans inhibited viral binding. The antiviral activity of heparin for both serotypes was independent of anticoagulant activity. N-sulfated regions of heparin were key for interactions of HSV with the cell surfaces since N-desulfation, but not N-deacetylation, abolished the antiviral activity. To assess the role of the heparin-binding glycoprotein, gC, in viral entry, we compared infection of wild-type (WT) and gC-deletion (gC-) viruses. We found a significant impairment in ability of HSV-1 gC- virus to infect primary human ectocervix. In contrast, deletion of gC from HSV-2 had no deleterious effect on HSV-2 infection of primary cells. These observations may reflect serotype differences in the role of gC in binding and entry for HSV-1 and HSV-2. In conclusion: 1) Primary human cervical and vaginal cells are susceptible to HSV infection in vitro and are a model system for study of genital tract infection; 2) HS is a receptor for viral binding; 3) for HSV-1, but not HSV-2, gC plays a key role in mediating viral entry into primary human cells; 4) serotype differences in gC may contribute to serotype differences in cell tropism.