Resistance of herpes simplex virus type 2 to neomycin maps to the N-terminal portion of glycoprotein C

102

Although heparan sulfate (HS) serves as an initial receptor for the binding of both herpes simplex virus type 1 (HSV-1) and HSV-2 to cell surfaces, the two serotypes differ in epidemiology, cell tropism, and ability to compete for viral receptors in vitro. These observations are not necessarily contradictory and can be explained if the two serotypes recognize different structural features of HS. To compare the specific features of HS important for the binding and infection of HSV-1 and HSV-2, we took advantage of structural similarities between heparin and cell surface HS and compared the abilities of chemically modified heparin compounds to inhibit plaque formation. We found that the antiviral activity of heparin for both serotypes was independent of anticoagulant activity. Moreover, specific negatively charged regions of the polysaccharide, including N sulfations and the carboxyl groups, are key structural features for interactions of both HSV-1 and HSV-2 with cell surfaces since N desulfation or carboxyl reduction abolished heparin's antiviral activity. In contrast, 6-O sulfations and 2-,3-O sulfations are important determinants primarily for HSV-1 infection. The O-desulfated heparins had little or no inhibitory effect on HSV-1 infection but inhibited HSV-2 infection. Using a series of intertypic recombinant mutant viruses, we found that susceptibility to O-desulfated heparins can be transferred to HSV-1 by the gene for glycoprotein C of HSV-2 (gC-2). This supports the notion that the envelope glycoproteins of HSV-1 and HSV-2 interact with different affinities for different structural features of heparin. To determine if the modified heparin compounds inhibited plaque formation by competing with cell surface HS for viral attachment, binding studies were also performed. As anticipated, most compounds inhibited binding and plaque formation in parallel. However, several compounds inhibited the binding of HSV-1 to cells during the initial attachment period at 4؇C; this inhibitory effect was reversed when the cells and inoculum were shifted to 37؇C. This temperature-dependent differential response to modified heparin compounds was evident primarily when glycoprotein C of HSV-1 (gC-1) was present in the virion envelope. Minimal temperaturedependent differences were seen for HSV-1 with gC-1 deleted and for HSV-2. These results suggest differences in the interactions of HSV-1 and HSV-2 with cell surface HS that may influence cell tropism.

Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

mentioning

confidence: 87%

See 1 more Smart Citation

Differences in the susceptibility of herpes simplex virus types 1 and 2 to modified heparin compounds suggest serotype differences in viral entry

Herold

Gerber

Belval

et al. 1996

102

“…Mapping studies have identified the first two-thirds of PRV gC, the first half of herpes simplex virus type 1 gC, and the middle two quarters of bovine herpesvirus 1 (BHV-1) gC as containing viral attachment domains, but the precise sequences that function as a receptor domain in these homologs have not been identified (6,14,21,34). Clusters of positively charged amino acids, some conforming to HBD consensus motifs (1), are present in these regions of the various gC homologs, and it has recently been shown that the deletion or alteration of some of these clusters leads to an attachment defect or the loss of heparin-binding activity (5,19,30).…”

Section: Discussionmentioning

confidence: 99%

A heterologous heparin-binding domain can promote functional attachment of a pseudorabies virus gC mutant to cell surfaces

Flynn

Ryan

1995

The efficient attachment of pseudorabies virus to cultured cells is dependent on an electrostatic interaction between negatively charged cell surface heparan sulfate and the viral envelope glycoprotein gC. Deletion of the first one-third of gC severely impairs virus attachment, but the mutant virions are still capable of entering cells and establishing an infection via a gC-independent pathway. This region of gC contains three clusters of positively charged amino acids that exactly or nearly conform to proposed consensus motifs for heparinbinding domains (HBDs), and the loss of one or more of these potential HBDs may be responsible for the observed attachment defect. To more directly show the involvement of HBDs in pseudorabies virus attachment to cells, we replaced the first one-third of gC with a single, biochemically defined HBD from apolipoprotein B-100. On the basis of the results of attachment, penetration, and heparin competition assays, the heterologous HBD mediated heparan sulfate-dependent virus attachment, but not to fully wild-type levels. Although the intermediate phenotype is not understood, the apolipoprotein B-100 HBD may represent the smallest defined amino acid sequence that promotes functional herpesvirus attachment to cultured cells.

“…Neomycin inhibits HSV-1 infection by competing with gC-1 for binding heparan sulfate glycosaminoglycans, which suggests that gC-1 and gC-2 recognize different moieties on cell surface heparan sulfate (16). The differ-ences in sensitivity to inhibition were shown to reside in the N-terminal 223 amino acids of gC-2, which appears to confer resistance to neomycin inhibition of infection (29). It is also becoming evident that the contributions of gB and gC to viral binding may be different for HSV-1 and HSV-2.…”

mentioning

confidence: 98%

Dextran sulfate can act as an artificial receptor to mediate a type-specific herpes simplex virus infection via glycoprotein B

Dyer

Banfield

Martindale

et al. 1997

Herpes simplex virus (HSV) adsorption to host cells is mediated, at least in part, by the interaction of viral glycoproteins with cell surface glycosaminoglycans such as heparan sulfate and chondroitin sulfate. To investigate the contribution of various cell surface components in the infection pathway, we isolated a mutant cell line, sog9, which is unable to synthesize glycosaminoglycans (B. W. Banfield, Y. Leduc, L. Esford, K. Schubert, and F. Tufaro, J. Virol. 69:3290-3298, 1995). Although HSV-1 and HSV-2 infection of sog9 cells is diminished, the cells are still infected at about 0.5% efficiency, which suggests that these cells normally express at least one nonglycosaminoglycan receptor. In this report, we used sog9 cells to test whether glycosaminoglycan analogs, such as dextran sulfate (DS), could functionally substitute for cellular glycosaminoglycans to initiate HSV infection. We show that high-molecular-weight DS added either prior to or during inoculation stimulated HSV-1 but not HSV-2 infection by up to 35-fold; DS added after viral adsorption had no effect on infection efficiency. Moreover, DS stimulated HSV-1 infection at 4؇C, indicating that this compound impinged on an early, energy-independent step in infection. Using radiolabeled virus, we showed that HSV-1 is more efficient than HSV-2 in adsorbing to DS immobilized on microtiter wells. This raised the possibility that only HSV-1 could engage additional receptors to initiate infection in the presence of DS. To determine which viral component(s) facilitated DS stimulation, a panel of intertypic recombinants and deletion mutant viruses was investigated. These assays showed that DS stimulation of infection is mediated primarily by gB-1. Thus, this study provides direct evidence that a principal role for cell surface glycosaminoglycans in HSV infection is to provide an efficient matrix for virus adsorption. Moreover, by using DS as an alternative adsorption matrix (a trans receptor), we uncovered a functional, type-specific interaction of HSV-1 with a cell surface receptor.