HCMV glycoprotein B subunit vaccine efficacy mediated by nonneutralizing antibody effector functions

Human cytomegalovirus (HCMV) is the most common congenital infection worldwide, frequently causing hearing loss and brain damage in afflicted infants. A vaccine to prevent maternal acquisition of HCMV during pregnancy is necessary to reduce the incidence of infant disease. The glycoprotein B (gB) + MF59 adjuvant subunit vaccine platform is the most successful HCMV vaccine tested to date, demonstrating ∼50% efficacy in preventing HCMV acquisition in multiple phase 2 trials. However, the mechanism of vaccine protection remains unknown. Plasma from 33 postpartum women gB/MF59 vaccinees at peak immunogenicity was tested for gB epitope specificity as well as neutralizing and nonneutralizing anti-HCMV effector functions and compared with an HCMV-seropositive cohort. gB/MF59 vaccination elicited IgG responses with gB-binding magnitude and avidity comparable to natural infection. Additionally, IgG subclass distribution was similar with predominant IgG1 and IgG3 responses induced by gB vaccination and HCMV infection. However, vaccine-elicited antibodies exhibited limited neutralization of the autologous virus, negligible neutralization of multiple heterologous strains, and limited binding responses against gB structural motifs targeted by neutralizing antibodies including AD-1, AD-2, and domain I. Vaccinees had high-magnitude IgG responses against AD-3 linear epitopes, demonstrating immunodominance against this nonneutralizing, cytosolic region. Finally, vaccine-elicited IgG robustly bound membrane-associated gB on the surface of transfected or HCMV-infected cells and mediated virion phagocytosis, although were poor mediators of NK cell activation. Altogether, these data suggest that nonneutralizing antibody functions, including virion phagocytosis, likely played a role in the observed 50% vaccine-mediated protection against HCMV acquisition.

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HCMV glycoprotein B subunit vaccine efficacy was mediated by non-neutralizing antibody effector functions

10.1101/246884 ◽

2018 ◽

Cited By ~ 2

Author(s):

Cody S. Nelson ◽

Tori Huffman ◽

Eduardo Cisneros de la Rosa ◽

Guanhua Xie ◽

Nathan Vandergrift ◽

...

Keyword(s):

Human Cytomegalovirus ◽

Vaccine Efficacy ◽

Subunit Vaccine ◽

Hcmv Infection ◽

Neutralizing Antibody ◽

The United States ◽

Glycoprotein B ◽

Vaccine Platform ◽

Effector Functions ◽

Epitope Specificity

AbstractHuman cytomegalovirus (HCMV) is the most common congenital infection worldwide, frequently causing hearing loss and brain damage in afflicted infants. A vaccine to prevent maternal acquisition of HCMV during pregnancy is necessary to reduce the incidence of infant disease. The glycoprotein B (gB) + MF59 adjuvant subunit vaccine platform is the most successful HCMV vaccine tested to-date, demonstrating approximately 50% efficacy in preventing HCMV acquisition in phase II trials. However, the mechanism of vaccine protection remains unknown. Plasma from 33 gB/MF59 vaccinees at peak immunogenicity was tested for gB epitope specificity as well as neutralizing and non-neutralizing anti-HCMV effector functions, and compared to an HCMV-seropositive cohort. gB/MF59 vaccination elicited IgG responses with gB-binding magnitude and avidity comparable to natural infection. Additionally, IgG subclass distribution was similar with predominant IgG1 and IgG3 responses induced by gB vaccination and HCMV infection. However, vaccine-elicited antibodies exhibited limited neutralization of the autologous virus, negligible neutralization of multiple heterologous strains, and limited binding responses against gB structural motifs targeted by neutralizing antibodies including AD-1, AD-2, and Domain I. Interestingly, vaccinees had high-magnitude IgG responses against AD-3 linear epitopes, demonstrating immunodominance against this non-neutralizing, cytosolic region. Finally, vaccine-elicited IgG robustly bound trimeric, membrane-associated gB on the surface of transfected or HCMV-infected cells and mediated virion phagocytosis, though were poor mediators of NK cell activation. Altogether, these data suggest that non-neutralizing antibody functions, including virion phagocytosis, likely played a role in the observed 50% vaccine-mediated protection against HCMV acquisition.SignificanceThe CDC estimates that every hour, a child is born in the United States with permanent neurologic disability resulting from human cytomegalovirus (HCMV) infection – more than is caused by Down syndrome, fetal alcohol syndrome, and neural tube defects combined. A maternal vaccine to block transmission of HCMV to the developing fetus is a necessary intervention to prevent these adverse outcomes. The gB/MF59 vaccine is the most successful tested clinically to-date, achieving 50% reduction in HCMV acquisition. This manuscript establishes the function and epitope specificity of the humoral response stimulated by this vaccine that may explain the partial vaccine efficacy. Understanding the mechanism of gB/MF59-elicited protective immune responses will guide rational design and evaluation of the next generation of HCMV vaccines.

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Novel Potent Neutralizing Antibodies Revealed the Domain I of HCMV Glycoprotein B for Vaccine Design

SSRN Electronic Journal ◽

10.2139/ssrn.3800383 ◽

2021 ◽

Author(s):

Changwen Wu ◽

Yuanbao Ai ◽

Yayu Wang ◽

Yueming Wang ◽

Tong Liu ◽

...

Keyword(s):

Neutralizing Antibodies ◽

Vaccine Design ◽

Glycoprotein B ◽

Domain I

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Protection from cytomegalovirus viremia following glycoprotein B vaccination is not dependent on neutralizing antibodies

Proceedings of the National Academy of Sciences ◽

10.1073/pnas.1800224115 ◽

2018 ◽

Vol 115 (24) ◽

pp. 6273-6278 ◽

Cited By ~ 53

Author(s):

Ilona Baraniak ◽

Barbara Kropff ◽

Lyn Ambrose ◽

Megan McIntosh ◽

Gary R. McLean ◽

...

Keyword(s):

Antibody Response ◽

Neutralizing Antibodies ◽

De Novo ◽

Natural Infection ◽

Neutralizing Antibody ◽

Glycoprotein B ◽

Solid Organ ◽

Viral Glycoprotein ◽

Viral Spread

Human cytomegalovirus (HCMV) is an important pathogen in transplant patients and in congenital infection. Previously, we demonstrated that vaccination with a recombinant viral glycoprotein B (gB)/MF59 adjuvant formulation before solid organ transplant reduced viral load parameters post transplant. Reduced posttransplant viremia was directly correlated with antibody titers against gB consistent with a humoral response against gB being important. Here we show that sera from the vaccinated seronegative patients displayed little evidence of a neutralizing antibody response against cell-free HCMV in vitro. Additionally, sera from seronegative vaccine recipients had minimal effect on the replication of a strain of HCMV engineered to be cell-associated in a viral spread assay. Furthermore, although natural infection can induce antibody-dependent cellular cytotoxicity (ADCC) responses, serological analysis of seronegative vaccinees again presented no evidence of a substantial ADCC-promoting antibody response being generated de novo. Finally, analyses for responses against major antigenic domains of gB following vaccination were variable, and their pattern was distinct compared with natural infection. Taken together, these data argue that the protective effect elicited by the gB vaccine is via a mechanism of action in seronegative vaccinees that cannot be explained by neutralization or the induction of ADCC. More generally, these data, which are derived from a human challenge model that demonstrated that the gB vaccine is protective, highlight the need for more sophisticated analyses of new HCMV vaccines over and above the quantification of an ability to induce potent neutralizing antibody responses in vitro.

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Immunological assessment of pediatric multisystem inflammatory syndrome related to COVID-19

Journal of the Pediatric Infectious Diseases Society ◽

10.1093/jpids/piaa142 ◽

2020 ◽

Author(s):

Serge Grazioli ◽

Fedora Tavaglione ◽

Giulia Torriani ◽

Noemie Wagner ◽

Marie Rohr ◽

...

Keyword(s):

T Cell ◽

T Cell Activation ◽

Neutralizing Antibodies ◽

Cell Activation ◽

Nk Cell ◽

University Hospitals ◽

Positive Serology ◽

Recent Infection ◽

Inflammatory Syndrome ◽

Post Infectious

Abstract Background Recently, cases of multisystem inflammatory syndrome in children (MIS-C) associated with COVID-19 have been reported worldwide. Negative RT-PCR testing associated with positive serology in most cases suggests a post-infectious syndrome. Because the pathophysiology of this syndrome is still poorly understood, extensive virological and immunological investigations are needed. Methods We report a series of four pediatric patients admitted to Geneva University Hospitals with persistent fever and laboratory evidence of inflammation meeting published definition of MIS-C related to COVID-19, to whom an extensive virological and immunological workup was performed. Results RT-PCRs on multiple anatomical compartments were negative whereas anti-SARS-CoV-2 IgA and IgG were strongly positive by ELISA and immunofluorescence. Both pseudo- and full virus neutralization assays showed the presence of neutralizing antibodies in all children, confirming a recent infection with SARS-CoV-2. Analyses of cytokine profiles revealed an elevation in all cytokines, as reported in adults with severe COVID-19. Although differing in clinical presentation, some features of MIS-C show phenotypic overlap with haemophagocytic lymphohistiocytosis (HLH). In contrast to patients with primary HLH, our patients showed normal perforin expression and NK cell degranulation. The levels of soluble IL-2 receptor (sIL-2R) correlated with the severity of disease, reflecting recent T-cell activation. Conclusion Our findings suggest that MIS-C related to COVID-19 is caused by a post-infectious inflammatory syndrome associated with elevation in all cytokines, and markers of recent T-cell activation (sIL-2R) occurring despite a strong and specific humoral response to SARS-CoV2. Further functional and genetic analyses are essential to better understand the mechanisms of host-pathogen interactions.

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Vaccination with Live Leishmania major and CpG DNA Promotes Interleukin-2 Production by Dermal Dendritic Cells and NK Cell Activation

Clinical and Vaccine Immunology ◽

10.1128/cvi.00249-09 ◽

2009 ◽

Vol 16 (11) ◽

pp. 1601-1606 ◽

Cited By ~ 10

Author(s):

Eva Maria Laabs ◽

Wenhui Wu ◽

Susana Mendez

Keyword(s):

Dendritic Cells ◽

Nk Cells ◽

Cell Activation ◽

Leishmania Major ◽

Nk Cell ◽

Natural Infection ◽

Interleukin 2 ◽

Innate Immune Responses ◽

Cpg Dna ◽

Ifn Γ

ABSTRACT Cutaneous leishmaniasis due to Leishmania major is an emerging, chronic parasitic disease that causes disfigurement and social stigmatization. Drug therapy is inadequate, and there is no vaccine. Inoculation of virulent parasites (leishmanization) is the only intervention that has ever provided protection, because it mimics natural infection and immunity, but it was discontinued due to safety concerns (uncontrolled vaccinal lesions). In an effort to retain the benefits (immunity) while avoiding the side effects (lesions) of leishmanization, we immunized C57BL/6 mice with L. major and CpG DNA (Lm/CpG). This combination prevented lesions while inducing immunity. Also, the vaccination with live parasites and the Toll-like receptor 9 agonist enhanced innate immune responses by activating dermal dendritic cells (DCs) to produce cytokines. Here we report that the Lm/CpG vaccine induced dermal DCs, but not bone marrow-derived DCs, to produce interleukin-2 (IL-2). The release of this unusual DC-derived cytokine was concomitant with a peak in numbers of NK cells that produced gamma interferon (IFN-γ) and also enhanced activation of proliferation of IFN-γ+ CD4+ T cells. Parasite growth was controlled in Lm/CpG-vaccinated animals. This is the first demonstration of the ability of dermal DCs to produce IL-2 and of the activation of NK cells by vaccination in the context of leishmaniasis. Understanding how the Lm/CpG vaccine enhances innate immunity may provide new tools to develop vaccines against L. major, other chronic infectious diseases, or other conditions, such as cancer.

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Dendritic cells for NK/LAK activation: rationale for multicellular immunotherapy in neuroblastoma patients

Blood ◽

10.1182/blood.v100.7.2554 ◽

2002 ◽

Vol 100 (7) ◽

pp. 2554-2561 ◽

Cited By ~ 41

Author(s):

Dominique Valteau-Couanet ◽

Christophe Leboulaire ◽

Kim Maincent ◽

Muriel Tournier ◽

Olivier Hartmann ◽

...

Keyword(s):

Dendritic Cells ◽

Cell Activation ◽

Nk Cell ◽

Residual Disease ◽

Interleukin 2 ◽

Lak Cells ◽

Peripheral Blood Stem Cells ◽

Term Survival ◽

Effector Functions ◽

Cell Functions

Natural killer (NK)/lymphokine-activated killer (LAK) cell-based immunotherapy could be beneficial against major histocompatibility complex class I–negative tumor residual disease such as neuroblastoma (NB), provided that interleukin 2 (IL-2) or surrogate nontoxic NK cell stimulatory factors could sustain NK cell activation and survival in vivo. Here we show that human monocyte–derived dendritic cells (MD-DCs) promote potent NK/LAK effector functions and long-term survival, circumventing the need for IL-2. This study demonstrates (1) the feasibility of differentiating granulocyte colony-stimulating factor–mobilized hematopoietic peripheral blood stem cells (PBSCs) into high numbers of functional MD-DCs and NK/LAK cells in a series of 12 children with stage 4 neuroblastoma (NB); (2) potent DC-mediated NK cell activation in autologous settings; (3) the reciprocal capacity of NK/LAK cells to turn immature DCs into maturing cells electively capable of triggering NK cell functions; and (4) the unique capacity of maturing DCs to sustain NK cell survival, superior to that achieved in IL-2. These data show a reciprocal interaction between DCs and NK/LAK cells, leading to the amplification of NK cell effector functions, and support the implementation of DC/NK cell–based immunotherapy for purging the graft and/or controlling minimal residual disease after autologous stem cell transplantation.

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

Journal of General Virology ◽

10.1099/0022-1317-80-8-2183 ◽

1999 ◽

Vol 80 (8) ◽

pp. 2183-2191 ◽

Cited By ~ 52

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.

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Mast Cells and Natural Killer Cells—A Potentially Critical Interaction

Viruses ◽

10.3390/v11060514 ◽

2019 ◽

Vol 11 (6) ◽

pp. 514 ◽

Cited By ~ 1

Author(s):

Liliana Portales-Cervantes ◽

Bassel Dawod ◽

Jean S. Marshall

Keyword(s):

Mast Cells ◽

Nk Cells ◽

Natural Killer ◽

Host Defense ◽

Cell Activation ◽

Nk Cell ◽

Mast Cell Activation ◽

Target Cells ◽

Effector Functions ◽

Mucosal Surfaces

Natural killer (NK) cells play critical roles in host defense against infectious agents or neoplastic cells. NK cells provide a rapid innate immune response including the killing of target cells without the need for priming. However, activated NK cells can show improved effector functions. Mast cells are also critical for early host defense against a variety of pathogens and are predominately located at mucosal surfaces and close to blood vessels. Our group has recently shown that virus-infected mast cells selectively recruit NK cells and positively modulate their functions through mechanisms dependent on soluble mediators, such as interferons. Here, we review the possible consequences of this interaction in both host defense and pathologies involving NK cell and mast cell activation.

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530 T-cell immunoglobulin– and mucin domain–containing (TIM)–3 downregulation in response to ex vivo activation and cancer targets correlates to NK cell functionality

Journal for ImmunoTherapy of Cancer ◽

10.1136/jitc-2020-sitc2020.0530 ◽

2020 ◽

Vol 8 (Suppl 3) ◽

pp. A566-A566

Author(s):

Tram Dao ◽

Sandro Matosevic ◽

Sagar Utturkar ◽

Nadia Lanman

Keyword(s):

Nk Cells ◽

Neutralizing Antibodies ◽

Nk Cell ◽

Ex Vivo ◽

Limited Information ◽

Effector Functions ◽

Wide Range ◽

Nk Cytotoxicity ◽

Cell Effector

BackgroundNatural killer (NK) cells are part of the innate immune system, but are capable of participating in both innate and adaptive immune responses due to their wide range of cytolytic activities, from degranulation, secretion of cytokines to antibody-dependent cell-mediated cytotoxicity. These are possible due to the cells’ ability to recognize self and non-self-entities via the net signal generated from their activating and inhibitory receptors upon engagement. TIM-3 is a part of the NK receptor repertoire, expressed commonly on different lymphocytes. In T cells, TIM-3 is established as an inhibitory marker. However, in NK cells, the role of TIM-3 could be agonistic or antagonistic to NK cytotoxicity based on the disease type and activation status, though limited information is known about its role in cancer and its correlation to NK cell effector functions.MethodsWe measured TIM-3 expression upon activation of human NK cells under various conditions. NK cells were isolated from peripheral blood of healthy donors and expanded either in K562-based feeder media or feeder-free OpTmizerTM media. After expansion, they were co-cultured for 4 hours with patient-derived glioblastoma multiforme cells (GBM43) at effector:target ratios of 2.5:1 and 10:1. To evaluate the effect of TIM-3 expression on NK cells, 7AAD/CFSE killing assays, CD107a degranulation and IFNγ secretion assays were carried out while blocking TIM-3 with neutralizing antibodies. Bioinformatics analysis of GBM patient RNAseq data was carried out to correlate TIM-3 expression with in vivo function, and this analysis is supplemented by phenotyping TIM-3 on NK cells isolated from patient samples in order to infer the role of this receptor in GBM.ResultsWe found that TIM-3 was downregulated on OpTmizerTM -cultured NK cells once exposed to cancer targets, and this correlated to a decreased in NK killing capacity when compared to feeder media-cultured NK cells, where the downregulation was not observed. Culturing NK cells in different derivatives of both media suggested that a combination of serum and cytokines can induce TIM-3 expression change to cancer targets. Flow cytometric assays revealed that while degranulation remained the same, the decreased in cytotoxicity corresponded to a decrease in IFNγ secretion. In GBM patient datasets, TIM-3 expression correlates to high IFN-γ levels and associates with both pro- and anti-tumorigenic functions. Here, we report a new role of TIM-3 in modulating NK functionality by correlating its loss to a loss in NK cell effector functions, and how its expression can be modified by ex vivo activation.ConclusionsTIM-3 expression on NK cells can be induced by ex vivo expansion, and this change in expression could influence NK cytotoxicity and cytokine secretion. Our data suggested that TIM-3 is not necessarily an inhibitory marker in GBM, and more likely to be a status marker or an activation limiter, working in conjunction with other receptors to modulate NK cell anti-tumor responses.Ethics ApprovalThis study was approved by Purdue Intuition’s Ethics Board, approval number [1804020540].

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Collaboration between the Fab and Fc contribute to maximal protection against SARS-CoV-2 in nonhuman primates following NVX-CoV2373 subunit vaccine with Matrix-M™ vaccination

10.1101/2021.02.05.429759 ◽

2021 ◽

Author(s):

Matthew J Gorman ◽

Nita Patel ◽

Mimi Guebre-Xabier ◽

Alex Zhu ◽

Caroline Atyeo ◽

...

Keyword(s):

Respiratory Tract ◽

Neutralizing Antibodies ◽

Lower Respiratory Tract ◽

Subunit Vaccine ◽

List Type ◽

Antigen Dose ◽

Virus Shedding ◽

Effector Functions ◽

Humoral Immune ◽

Functional Antibodies

AbstractRecently approved vaccines have already shown remarkable protection in limiting SARS-CoV-2 associated disease. However, immunologic mechanism(s) of protection, as well as how boosting alters immunity to wildtype and newly emerging strains, remain incompletely understood. Here we deeply profiled the humoral immune response in a cohort of non-human primates immunized with a stable recombinant full-length SARS-CoV-2 spike (S) glycoprotein (NVX-CoV2373) at two dose levels, administered as a single or two-dose regimen with a saponin-based adjuvant Matrix-M™. While antigen dose had some effect on Fc-effector profiles, both antigen dose and boosting significantly altered overall titers, neutralization and Fc-effector profiles, driving unique vaccine-induced antibody fingerprints. Combined differences in antibody effector functions and neutralization were strongly associated with distinct levels of protection in the upper and lower respiratory tract, pointing to the presence of combined, but distinct, compartment-specific neutralization and Fc-mechanisms as key determinants of protective immunity against infection. Moreover, NVX-CoV2373 elicited antibodies functionally target emerging SARS-CoV-2 variants, collectively pointing to the critical collaborative role for Fab and Fc in driving maximal protection against SARS-CoV-2. Collectively, the data presented here suggest that a single dose may prevent disease, but that two doses may be essential to block further transmission of SARS-CoV-2 and emerging variants.HighlightsNVX-CoV2373 subunit vaccine elicits receptor blocking, virus neutralizing antibodies, and Fc-effector functional antibodies.The vaccine protects against respiratory tract infection and virus shedding in non-human primates (NHPs).Both neutralizing and Fc-effector functions contribute to protection, potentially through different mechanisms in the upper and lower respiratory tract.Both macaque and human vaccine-induced antibodies exhibit altered Fc-receptor binding to emerging mutants.

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