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Journal of Virology, December 1999, p. 9879-9890, Vol. 73, No. 12
School of Dental
Medicine,1 Center for Oral Health
Research,2 and School of Veterinary
Medicine,3 University of Pennsylvania,
Philadelphia, Pennsylvania 19104
Received 28 May 1999/Accepted 24 August 1999
Herpes simplex virus (HSV) entry is dependent on the interaction of
virion glycoprotein D (gD) with one of several cellular receptors. We
previously showed that gD binds specifically to two structurally
dissimilar receptors, HveA and HveC. We have continued our studies by
using (i) a panel of baculovirus-produced gD molecules with various
C-terminal truncations and (ii) a series of gD mutants with
nonoverlapping 3-amino-acid deletions between residues 222 and 254. Binding of the potent neutralizing monoclonal antibody (MAb) DL11
(group Ib) was unaffected in forms of gD containing residues 1 to 250 but was greatly diminished in molecules truncated at residue 240 or
234. Both receptor binding and blocking of HSV infection were also
affected by these C-terminal truncations. gD-1(234t) bound weakly to
both HveA and HveC as determined by enzyme-linked immunosorbent assay
(ELISA) and failed to block infection. Interestingly, gD-1(240t) bound
well to both receptors but blocked infection poorly, indicating that
receptor binding as measured by ELISA is not the only gD function
required for blocking. Optical biosensor studies showed that while
gD-1(240t) bound HveC with an affinity similar to that of gD-1(306t),
the rates of complex formation and dissociation were significantly faster than for gD-1(306t). Complementation analysis showed that any
3-amino-acid deletion between residues 222 and 251 of gD resulted in a
nonfunctional protein. Among this set of proteins, three had lost DL11
reactivity (those with deletions between residues 222 and 230). One of
these proteins (deletion 222-224) was expressed as a soluble form in
the baculovirus system. This protein did not react with DL11, bound to
both HveA and HveC poorly as shown by ELISA, and failed to block HSV
infection. Since this protein was bound by several other MAbs that
recognize discontinuous epitopes, we conclude that residues 222 to 224 are critical for gD function. We propose that the potent
virus-neutralizing activity of DL11 (and other group Ib MAbs) likely
reflects an overlap between its epitope and a receptor-binding domain
of gD.
0022-538X/99/$04.00+0
Copyright © 1999, American Society for Microbiology. All rights reserved.
The Major Neutralizing Antigenic Site on Herpes
Simplex Virus Glycoprotein D Overlaps a Receptor-Binding
Domain


*
Corresponding author. Mailing address: 212 Levy Bldg.,
School of Dental Medicine, University of Pennsylvania, Philadelphia, PA
19104. Phone: (215) 898-6553. Fax: (215) 898-8385. E-mail: whitbeck{at}biochem.dental.upenn.edu.
Present address: Department of Microbiology and Immunology,
Louisiana State University School of Medicine, Shreveport, LA 71130.
Present address: Department of Microbiology, University of Nevada
at Reno, Reno, NV 89557.
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