Function of Human Cytomegalovirus Glycoprotein B: Syncytium Formation in Cells Constitutively Expressing gB Is Blocked by Virus-Neutralizing Antibodies

Virology ◽  
1994 ◽  
Vol 201 (2) ◽  
pp. 263-276 ◽  
Author(s):  
Sharof Tugizov ◽  
David Navarro ◽  
Pedro Paz ◽  
Yilong Wang ◽  
Ishtiaq Qadri ◽  
...  
Keyword(s):  
Human Cytomegalovirus ◽  
Neutralizing Antibodies ◽  
Syncytium Formation ◽  
Glycoprotein B ◽  
In Cells

scholarly journals Antigenic domain 1 of human cytomegalovirus glycoprotein B induces a multitude of different antibodies which, when combined, results in incomplete virus neutralization

1999 ◽  
Vol 80 (8) ◽  
pp. 2183-2191 ◽  
Author(s):  
Andrea Speckner ◽  
Diana Glykofrydes ◽  
Mats Ohlin ◽  
Michael Mach
Keyword(s):  
Human Cytomegalovirus ◽  
Neutralizing Antibodies ◽  
Natural Infection ◽  
Antibody Binding ◽  
Virus Neutralization ◽  
Single Amino Acid ◽  
Glycoprotein B ◽  
Considerable Proportion ◽  
Mutant Proteins ◽  
Neutralization Capacity

Glycoprotein B (gB, gpUL55) is the major antigen for the induction of neutralizing antibodies against human cytomegalovirus (HCMV), making it an attractive molecule for active and passive immunoprophylaxis. The region between aa 552 and 635 of HCMV gB (termed AD-1) has been identified as the immunodominant target for the humoral immune response following natural infection. AD-1 represents a complex domain which requires a minimal continuous sequence of more than 70 aa for antibody binding. Neutralizing as well as non-neutralizing antibodies can bind to AD-1 in a competitive fashion. The fine specificity of AD-1-binding monoclonal antibodies (MAbs) and affinity-purified human polyclonal antibodies was analysed by using recombinant proteins containing single amino acid substitutions spanning the entire AD-1 domain. Our results revealed that all MAbs had individual patterns of binding to the mutant proteins indicating the presence of a considerable number of distinct antibody-binding sites on AD-1. The neutralization capacity of antibodies could not be predicted from their binding pattern to AD-1 mutant proteins. Polyclonal human antibodies purified from different convalescent sera showed identical binding patterns to the mutant proteins suggesting that the combined antibody specificities present in human sera are comparable between individuals. Neutralization capacities of polyclonal human AD-1 antibodies did not exceed 50% indicating that, during natural infection, a considerable proportion of non-neutralizing antibodies are induced and thus might provide an effective mechanism to evade complete virus neutralization.

scholarly journals Potent Bispecific Neutralizing Antibody Targeting Glycoprotein B and the gH/gL/pUL128/130/131 Complex of Human Cytomegalovirus

2020 ◽  
Vol 65 (3) ◽  
Author(s):  
Hang Su ◽  
Xiaohua Ye ◽  
Daniel C. Freed ◽  
Leike Li ◽  
Zhiqiang Ku ◽  
...  
Keyword(s):  
Human Cytomegalovirus ◽  
Neutralizing Antibodies ◽  
Developmental Disorders ◽  
Bispecific Antibody ◽  
Hcmv Infection ◽  
Rhesus Macaques ◽  
Congenital Infection ◽  
Neutralizing Antibody ◽  
Glycoprotein B ◽  
Single Chain

ABSTRACT Human cytomegalovirus (HCMV) is a ubiquitous pathogen that can cause developmental disorders following congenital infection and life-threatening complications among transplant patients. Potent neutralizing monoclonal antibodies (MAbs) are promising drug candidates against HCMV infection. HCMV can infect a broad range of cell types. Therefore, single neutralizing antibodies targeting one HCMV glycoprotein often lack either potency or broad cell-type coverage. We previously characterized two human-derived HCMV neutralizing MAbs. One was the broadly neutralizing MAb 3-25, which targets the antigenic domain 2 of glycoprotein B (gB). The other was the highly potent MAb 2-18, which specifically recognizes the gH/gL/pUL128/130/131 complex (pentamer). To combine the strengths of gB- and pentamer-targeting MAbs, we developed an IgG–single-chain variable fragment (scFv) bispecific antibody by fusing the 2-18 scFv to the heavy-chain C terminus of MAb 3-25. The resulting bispecific antibody showed high-affinity binding to both gB and pentamer. Functionally, the bispecific antibody demonstrated a combined neutralization breadth and potency of the parental MAbs in multiple cell lines and inhibited postinfection viral spreading. Furthermore, the bispecific antibody was easily produced in CHO cells at a yield above 1 g/liter and showed a single-dose pharmacokinetic profile comparable to that of parental MAb 3-25 in rhesus macaques. Importantly, the bispecific antibody retained broadly and potent neutralizing activity after 21 days in circulation. Taken together, our research provides a proof-of-concept study for developing bispecific neutralizing antibody therapies against HCMV infection.

scholarly journals Mutated Forms of Human Cytomegalovirus Glycoprotein B Are Impaired in Inducing Syncytium Formation

Virology ◽  
1995 ◽  
Vol 209 (2) ◽  
pp. 580-591 ◽  
Author(s):  
Sharof Tugizov ◽  
Yilong Wang ◽  
Ishtiaq Qadri ◽  
David Navarro ◽  
Ekaterina Maidji ◽  
...  
Keyword(s):  
Human Cytomegalovirus ◽  
Syncytium Formation ◽  
Glycoprotein B

scholarly journals Recombinant Modified Vaccinia Virus Ankara Expressing a Soluble Form of Glycoprotein B Causes Durable Immunity and Neutralizing Antibodies against Multiple Strains of Human Cytomegalovirus

2004 ◽  
Vol 78 (8) ◽  
pp. 3965-3976 ◽  
Author(s):  
Zhongde Wang ◽  
Corinna La Rosa ◽  
Rebecca Maas ◽  
Heang Ly ◽  
John Brewer ◽  
...  
Keyword(s):  
Vaccinia Virus ◽  
Human Cytomegalovirus ◽  
Neutralizing Antibodies ◽  
Natural Infection ◽  
Glycoprotein B ◽  
Soluble Form ◽  
Effective Vaccine ◽  
Viral Pathogen ◽  
Modified Vaccinia Virus Ankara ◽  
Viral Vaccine

ABSTRACT Human cytomegalovirus (CMV) is a viral pathogen that infects both genders, who remain asymptomatic unless they receive immunosuppressive drugs or acquire infections that cause reactivation of latent virus. CMV infection also causes serious birth defects following primary maternal infection during gestation. A safe and effective vaccine to limit disease in this population continues to be elusive. A well-studied antigen is glycoprotein B (gB), which is the principal target of neutralizing antibodies (NAb) towards CMV in humans and has been implicated as the viral partner in the receptor-mediated infection by CMV in a variety of cell types. Antibody-mediated virus neutralization has been proposed as a mechanism by which host immunity could modify primary infection. Towards this goal, an attenuated poxvirus, modified vaccinia virus Ankara (MVA), has been constructed to express soluble CMV gB (gB680-MVA) to induce CMV NAb. Very high levels of gB-specific CMV NAb were produced after two doses of the viral vaccine. NAb were durable within a twofold range for up to 6 months. Neutralization titers developed in immunized mice are equivalent to titers found clinically after natural infection. This viral vaccine, expressing gB derived from CMV strain AD169, induced antibodies that neutralized CMV strains of three different genotypes. Remarkably, preexisting MVA and vaccinia virus (poxvirus) immunity did not interfere with subsequent immunizations of gB680-MVA. The safety characteristics of MVA, combined with the robust immune response to CMV gB, suggest that this approach could be rapidly translated into the clinic.

scholarly journals B Cell Repertoire Analysis Identifies New Antigenic Domains on Glycoprotein B of Human Cytomegalovirus which Are Target of Neutralizing Antibodies

2011 ◽  
Vol 7 (8) ◽  
pp. e1002172 ◽  
Author(s):  
Sonja Pötzsch ◽  
Nadja Spindler ◽  
Anna-Katharina Wiegers ◽  
Tanja Fisch ◽  
Pia Rücker ◽  
...  
Keyword(s):  
B Cell ◽  
Human Cytomegalovirus ◽  
Neutralizing Antibodies ◽  
Glycoprotein B ◽  
Cell Repertoire ◽  
Repertoire Analysis ◽  
B Cell Repertoire ◽  
Antigenic Domains

scholarly journals Enveloped Virus-Like Particle Expression of Human Cytomegalovirus Glycoprotein B Antigen Induces Antibodies with Potent and Broad Neutralizing Activity

2013 ◽  
Vol 21 (2) ◽  
pp. 174-180 ◽  
Author(s):  
Marc Kirchmeier ◽  
Anne-Catherine Fluckiger ◽  
Catalina Soare ◽  
Jasminka Bozic ◽  
Barthelemy Ontsouka ◽  
...  
Keyword(s):  
Epithelial Cell ◽  
Human Cytomegalovirus ◽  
Neutralizing Antibodies ◽  
Matrix Protein ◽  
High Titer ◽  
Neutralizing Antibody ◽  
Glycoprotein B ◽  
Solid Organ ◽  
Neutralizing Activity ◽  
Enveloped Virus

ABSTRACTA prophylactic vaccine to prevent the congenital transmission of human cytomegalovirus (HCMV) in newborns and to reduce life-threatening disease in immunosuppressed recipients of HCMV-infected solid organ transplants is highly desirable. Neutralizing antibodies against HCMV confer significant protection against infection, and glycoprotein B (gB) is a major target of such neutralizing antibodies. However, one shortcoming of past HCMV vaccines may have been their failure to induce high-titer persistent neutralizing antibody responses that prevent the infection of epithelial cells. We used enveloped virus-like particles (eVLPs), in which particles were produced in cells after the expression of murine leukemia virus (MLV) viral matrix protein Gag, to express either full-length CMV gB (gB eVLPs) or the full extracellular domain of CMV gB fused with the transmembrane and cytoplasmic domains from vesicular stomatitis virus (VSV)-G protein (gB-G eVLPs). gB-G-expressing eVLPs induced potent neutralizing antibodies in mice with a much greater propensity toward epithelial cell-neutralizing activity than that induced with soluble recombinant gB protein. An analysis of gB antibody binding titers and T-helper cell responses demonstrated that high neutralizing antibody titers were not simply due to enhanced immunogenicity of the gB-G eVLPs. The cells transiently transfected with gB-G but not gB plasmid formed syncytia, consistent with a prefusion gB conformation like those of infected cells and viral particles. Two of the five gB-G eVLP-induced monoclonal antibodies we examined in detail had neutralizing activities, one of which possessed particularly potent epithelial cell-neutralizing activity. These data differentiate gB-G eVLPs from gB antigens used in the past and support their use in a CMV vaccine candidate with improved neutralizing activity against epithelial cell infection.

scholarly journals Identification of a Neutralizing Epitope within Antigenic Domain 5 of Glycoprotein B of Human Cytomegalovirus

2014 ◽  
Vol 89 (1) ◽  
pp. 361-372 ◽  
Author(s):  
Anna-Katharina Wiegers ◽  
Heinrich Sticht ◽  
Thomas H. Winkler ◽  
William J. Britt ◽  
Michael Mach
Keyword(s):  
Human Cytomegalovirus ◽  
Neutralizing Antibodies ◽  
Mutational Analysis ◽  
Antibody Responses ◽  
Health Concern ◽  
Glycoprotein B ◽  
Protective Capacity ◽  
Important Target ◽  
Hcmv Disease ◽  
Antigenic Domain

ABSTRACTHuman cytomegalovirus (HCMV) is an important, ubiquitous pathogen that causes severe clinical disease in immunocompromised individuals, such as organ transplant recipients and infants infectedin utero. The envelope glycoprotein B (gB) of HCMV is a major antigen for the induction of virus-neutralizing antibodies. We have begun to define target structures within gB that are recognized by virus-neutralizing antibodies. Antigenic domain 5 (AD-5) of gB has been identified as an important target for neutralizing antibodies in studies using human monoclonal antibodies (MAbs). Anti-AD-5 MAbs share a target site on gB, despite originating from different, healthy, HCMV-infected donors. Mutational analysis of AD-5 identified tyrosine 280 in combination with other surface-exposed residues (the YNND epitope) as critical for antibody binding. The YNND epitope is strictly conserved among different HCMV strains. Recombinant viruses carrying YNND mutations in AD-5 were resistant to virus-neutralizing MAbs. Competition enzyme-linked immunosorbent assays (ELISAs) with human HCMV-convalescent-phase sera from unselected donors confirmed the conserved antibody response for the YNND epitope in HCMV-infected individuals and, because a significant fraction of the gB AD-5 response was directed against the YNND epitope, further argued that this epitope is a major target of anti-AD-5 antibody responses. In addition, affinity-purified polyclonal anti-AD-5 antibodies prepared from individual sera showed reactivity to AD-5 and neutralization activity toward gB mutant viruses that were similar to those of AD-5-specific MAbs. Taken together, our data indicate that the YNND epitope represents an important target for anti-gB antibody responses as well as for anti-AD-5 virus-neutralizing antibodies.IMPORTANCEHCMV is a major global health concern, and a vaccine to prevent HCMV disease is a widely recognized medical need. Glycoprotein B of HCMV is an important target for neutralizing antibodies and hence an interesting molecule for intervention strategies, e.g., vaccination. Mapping the target structures of neutralizing antibodies induced by naturally occurring HCMV infection can aid in defining the properties required for a protective capacity of vaccine antigens. The data presented here extend our knowledge of neutralizing epitopes within gB to include AD-5. Collectively, our data will contribute to optimal vaccine design and development of antibody-based therapies.

scholarly journals Antigenic Domain 1 Is Required for Oligomerization of Human Cytomegalovirus Glycoprotein B

2005 ◽  
Vol 79 (7) ◽  
pp. 4066-4079 ◽  
Author(s):  
William J. Britt ◽  
Michael A. Jarvis ◽  
Derek D. Drummond ◽  
Michael Mach
Keyword(s):  
Human Cytomegalovirus ◽  
Neutralizing Antibodies ◽  
Glycoprotein B ◽  
Structural Domain ◽  
Bacterial Artificial Chromosomes ◽  
Artificial Chromosomes ◽  
Antibody Binding Site ◽  
Virion Envelope ◽  
Antigenic Domain 1 ◽  
Antigenic Domain

ABSTRACT Human cytomegalovirus (HCMV) glycoprotein B (gB) is an abundant virion envelope protein that has been shown to be essential for the infectivity of HCMV. HCMV gB is also one of the most immunogenic virus-encoded proteins, and a significant fraction of virus neutralizing antibodies are directed at gB. A linear domain of gB designated AD-1 (antigenic domain 1) represents a dominant antibody binding site on this protein. AD-1 from clinical isolates of HCMV exhibits little sequence variation, suggesting that AD-1 plays an essential role in gB structure or function. We investigated this possibility by examining the role of AD-1 in early steps of gB synthesis. Our results from studies using eukaryotic cells indicated that amino acid (aa) 635 of the gB sequence represented the carboxyl-terminal limit of this domain and that deletion of aa 560 to 640 of the gB sequence resulted in loss of AD-1 expression. AD-1 was shown to be required for oligomerization of gB. Mutation of cysteine at either position 573 or 610 in AD-1 resulted in loss of its reactivity with AD-1-specific monoclonal antibodies and gB oligomerization. Infectious virus could not be recovered from HCMV bacterial artificial chromosomes following introduction of these mutations into the HCMV genome, suggesting that AD-1 was an essential structural domain required for gB function in the replicative cycle of HCMV. Sequence alignment of AD-1 with homologous regions of gBs from other herpesviruses demonstrated significant relatedness, raising the possibility that this domain may contribute to multimerization of gBs in other herpesviruses.

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