Identification of Structural Features of Heparin Required for Inhibition of Herpes Simplex Virus Type 1 Binding

Abstract

Binding of HSV-1 to cells is mediated by interactions of virion glycoproteins gC and/or gB with heparin sulfate (HS) glycosaminoglycans on cell surface proteoglycans. HS and the related glycosaminoglycan, heparin, comprise a family of heterogeneous carbohydrates composed of long, unbranched polysaccharides modified, for example, by sulfations and acetylations. To define the specific features of HS important for viral binding, we took advantage of the structural similarities between heparin and cell surface HS and compared the ability of chemically modified heparin compounds to inhibit the binding of viral particles to the cell surface and subsequent plaque formation. Because binding presumably involves multiple, complex interactions between both known heparin-binding glycoproteins, gC and gB, and cell surface HS, we compared the effects of modified heparin compounds on the binding and subsequent plaque formation of wild-type and gC-negative strains of HSV-1 and, in select cases, the binding of gB-negative virus to cells. We identified specific structural features of heparin essential for the inhibition of viral binding. For example, both N-sulfation and 6-O-sulfation must be important determinants since desulfation of heparin at these sites abolished or decreased the antiviral activity of heparin. Moreover, we found that the antiviral activity of heparin was independent of its anticoagulant activity. Carboxyl-reduced and 2,3-O-desulfated heparin selectively inhibited binding of gC-positive viruses (wild-type or a gB-negative strain) to cells, but had little or no inhibitory effect on binding and subsequent plaque formation for a gC-deletion virus. These results suggest that gC and gB interact with different structural features of HS.

Herpes Simplex Virus Glycoprotein B Binds to Cell Surfaces Independently of Heparan Sulfate and Blocks Virus Entry

“…Moreover, purified soluble gB from bovine herpesvirus type 1 binds to live cells with a K D of 5 ϫ 10 Ϫ7 M, a value similar to that reported for the HSV-2 gB/heparin complex (34). This suggests that the affinity of gB for heparin is conserved in related alphaherpesviruses, which is not surprising, since gB is the most conserved glycoprotein in the family (46); we propose that the affinity of gB1 for heparin is similar to that reported for gB2 (20,62). Another possibility is that the initial binding of gB to HSPG may enhance attachment of gB to a second type of receptor.…”

Recombinant adeno-associated virus purification using novel methods improves infectious titer and yield

“…The degree of sulfation strongly correlates with the virus-binding capacity of HS. 30 Therefore, we anticipated that heparinized matrices from different vendors would display different affinity towards rAAV. To develop the method, we tested several heparin ligand-containing media, including ACTI-Disk 50 (Arbor Technologies), which is a heparinized filter disk, three column chromatography media manufactured by Sigma (St Louis, MO, USA), Heparin-Agarose Type I, Heparin-Agarose Type II-S, Heparin Agarose Type III-S, and finally Affi-Gel Heparin Gel (Bio-Rad, Hercules, CA, USA).…”

HSV trafficking and development of gene therapy vectors with applications in the nervous system

“…Binding to cell surface glycosaminoglycans (GAGs), primarily heparan sulfate (HS), [43][44][45][46][47][48][49] is mediated by exposed domains of glycoproteins C 50 and B. 51,52 The HS-binding domains were mapped to regions within gC, 49,53 including amino acids 136-152, and a short stretch of lysine residues encompassing amino acids 68-76 within gB. 54,55 Deletion of gC, and the HSbinding domain of gB, in a single mutant virus impairs binding (ie slower kinetics) to an extent similar to the reduced binding of wild-type virus on HS-deficient cells.…”