An Analysis of the Biological Properties of Monoclonal Antibodies against Glycoprotein D of Herpes Simplex Virus and Identification of Amino Acid Substitutions that Confer Resistance to Neutralization

Abstract

SUMMARYFour monoclonal antibodies to glycoprotein D (gD) of herpes simplex virus (HSV) types 1 and 2 neutralized virus in the presence of complement but exhibited diverse activities in its absence. Amino acid substitutions that conferred resistance to neutralization by each antibody were identified by deriving the nucleotide sequence of the gD gene from resistant mutants. Each antibody selected a substitution from different parts of the molecule and mutants resistant to a single antibody always arose from the same mutation. One of the antibodies reacted with a synthetic oligopeptide corresponding to the region of the molecule in which amino acid substitution conferred resistance, but the remaining three antibodies failed to react with predicted oligopeptide targets. These antibodies may therefore react with 'discontinuous' epitopes, a view supported by the observation that two of these three antibodies competed with each other in binding assays despite the fact that substitutions conferring resistance to neutralization arose nearly 100 residues apart in the primary sequence. The four antibodies had very different biological properties. One antibody neutralized infectivity but did not inhibit cell fusion, one antibody inhibited cell fusion but did not neutralize, while a third antibody had both activities. One antibody had neither activity but enhanced the infectivity of HSV-2 in a type-specific manner. The ability of antibodies to inhibit cell fusion by syncytial virus strains correlated with an ability to prevent plaque enlargement by a non-syncytial virus strain, implying a role for gD in the intercellular spread of virus that is independent of the syncytial phenotype. We found no correlation between neutralizing activity and anti-fusion activity suggesting that, while gD is involved in cell fusion, it has at least one other function which is required for infectivity.

Excretion of Non-infectious Virus Particles Lacking Glycoprotein H by a Temperature-sensitive Mutant of Herpes Simplex Virus Type 1: Evidence that gH Is Essential for Virion Infectivity

“…VP16 (Vmw65) and glycoprotein D were detected with monoclonal antibodies LPI and LP14 respectively (McLean et al, 1982;Minson et al, 1986). Antibody LP11 is a murine monoclonal antibody against HSV-1 gH (Buckmaster et al, 1984).…”

Induction of protective immunity with antibody to herpes simplex virus type 1 glycoprotein H (gH) and analysis of the immune response to gH expressed in recombinant vaccinia virus

“…AntitrpE-gH is a rabbit serum raised against a tryptophan E-HSV-1 gH fusion protein (Desai et al, 1988). Neutralization assays were performed as described by Minson et al (1986). Preparation of infected call lysates, immunoprecipitation, detection of enzymes by Western blotting and immunofluorescence were as described by Gompels & Minson (1989).…”

Glycoprotein 60 of equine herpesvirus type 1 is a homologue of herpes simplex virus glycoprotein D and plays a major role in penetration of cells

“…None of the antibodies showed any effect on the cell-cell fusion typically seen with EHV-l-infected RK cells (data not shown). Anti-HSV-1 gD MAbs that neutralized infectivity in the absence of complement also showed no effect on cell-cell fusion (Minson et al, 1986), whereas other complement-dependent neutralizing antibodies affected the fusion processes.…”

“…In addition to affecting penetration, MAbs to HSV-1 gD have been shown to affect cell-cell fusion (Noble et al, 1983;Minson et al, 1986). The EHV-1 antibodies used to block virus penetration were also tested for effects on cell-cell fusion.…”