Longitudinal Isolation of Potent Near-Germline SARS-CoV-2-Neutralizing Antibodies from COVID-19 Patients.

The SARS-CoV-2 pandemic has unprecedented implications for public health, social life, and the world economy. Because approved drugs and vaccines are limited or not available, new options for COVID-19 treatment and prevention are in high demand. To identify SARS-CoV-2-neutralizing antibodies, we analyzed the antibody response of 12 COVID-19 patients from 8 to 69 days after diagnosis. By screening 4,313 SARS-CoV-2-reactive B cells, we isolated 255 antibodies from different time points as early as 8 days after diagnosis. Of these, 28 potently neutralized authentic SARS-CoV-2 with IC100 as low as 0.04 µg/mL, showing a broad spectrum of variable (V) genes and low levels of somatic mutations. Interestingly, potential precursor sequences were identified in naive B cell repertoires from 48 healthy individuals who were sampled before the COVID-19 pandemic. Our results demonstrate that SARS-CoV-2-neutralizing antibodies are readily generated from a diverse pool of precursors, fostering hope for rapid induction of a protective immune response upon vaccination.

Self-amplifying RNA vaccine protects mice against lethal Ebola virus infection.

Emerging and re-emerging viruses, such as Zaire Ebola virus (EBOV), pose a global threat and require immediate countermeasures, including the rapid development of effective vaccines that are easy to manufacture. Synthetic self-amplifying RNAs (saRNAs) attend to these needs, being safe and strong immune stimulators that can be inexpensively produced in large quantities, using cell-free systems and good manufacturing practice. Here, the first goal was to develop and optimize an anti-EBOV saRNA-based vaccine in terms of its antigen composition and route of administration. Vaccinating mice with saRNAs expressing the EBOV glycoprotein (GP) alone or in combination with the nucleoprotein (NP) elicited antigen-specific immune responses. GP-specific antibodies showed neutralizing activity against EBOV. Strong CD4+ T cell response against NP and GP and CD8+ T cell response against NP were detected by ELISpot assays. Intramuscular vaccination with saRNAs conferred better immune response than intradermal. Finally, mice vaccinated in a prime-boost regimen with saRNAs encoding both GP and NP or with GP alone survived an EBOV infection. In addition, a single dose of GP and NP saRNAs was also protective against fatal EBOV infection. Overall, saRNAs expressing viral antigens represent a promising vaccine platform.

Immunogenicity and efficacy of the COVID-19 candidate vector vaccine MVA-SARS-2-S in preclinical vaccination.

Severe acute respiratory syndrome (SARS) coronavirus 2 (SARS-CoV-2) has emerged as the infectious agent causing the pandemic coronavirus disease 2019 (COVID-19) with dramatic consequences for global human health and economics. Previously, we reached clinical evaluation with our vector vaccine based on modified vaccinia virus Ankara (MVA) against the Middle East respiratory syndrome coronavirus (MERS-CoV), which causes an infection in humans similar to SARS and COVID-19. Here, we describe the construction and preclinical characterization of a recombinant MVA expressing full-length SARS-CoV-2 spike (S) protein (MVA-SARS-2-S). Genetic stability and growth characteristics of MVA-SARS-2-S, plus its robust expression of S protein as antigen, make it a suitable candidate vaccine for industrial-scale production. Vaccinated mice produced S-specific CD8+ T cells and serum antibodies binding to S protein that neutralized SARS-CoV-2. Prime-boost vaccination with MVA-SARS-2-S protected mice sensitized with a human ACE2-expressing adenovirus from SARS-CoV-2 infection. MVA-SARS-2-S is currently being investigated in a phase I clinical trial as aspirant for developing a safe and efficacious vaccine against COVID-19.

Cyclophilin inhibitors restrict Middle East respiratory syndrome coronavirus via interferon-λ in vitro and in mice.

While severe coronavirus infections, including Middle East respiratory syndrome coronavirus (MERS-CoV), cause lung injury with high mortality rates, protective treatment strategies are not approved for clinical use.We elucidated the molecular mechanisms by which the cyclophilin inhibitors cyclosporin A (CsA) and alisporivir (ALV) restrict MERS-CoV to validate their suitability as readily available therapy in MERS-CoV infection.Calu-3 cells and primary human alveolar epithelial cells (hAECs) were infected with MERS-CoV and treated with CsA or ALV or inhibitors targeting cyclophilin inhibitor-regulated molecules including calcineurin, nuclear factor of activated T-cells (NFATs) or mitogen-activated protein kinases. Novel CsA-induced pathways were identified by RNA sequencing and manipulated by gene knockdown or neutralising antibodies. Viral replication was quantified by quantitative real-time PCR and 50% tissue culture infective dose. Data were validated in a murine MERS-CoV infection model.Both CsA and ALV reduced MERS-CoV titres and viral RNA replication in Calu-3 cells and hAECs, improving epithelial integrity. While neither calcineurin nor NFAT inhibition reduced MERS-CoV propagation, blockade of c-Jun N-terminal kinase diminished infectious viral particle release but not RNA accumulation. Importantly, CsA induced interferon regulatory factor 1 (IRF1), a pronounced type III interferon (IFNλ) response and expression of antiviral genes. Downregulation of IRF1 or IFNλ increased MERS-CoV propagation in the presence of CsA. Importantly, oral application of CsA reduced MERS-CoV replication in vivo, correlating with elevated lung IFNλ levels and improved outcome.We provide evidence that cyclophilin inhibitors efficiently decrease MERS-CoV replication in vitro and in vivo via upregulation of inflammatory antiviral cell responses, in particular IFNλ. CsA might therefore represent a promising candidate for treating MERS-CoV infection.

Intranasal Borna Disease Virus (BoDV-1) Infection: Insights into Initial Steps and Potential Contagiosity.

Mammalian Bornavirus (BoDV-1) typically causes a fatal neurologic disorder in horses and sheep, and was recently shown to cause fatal encephalitis in humans with and without transplant reception. It has been suggested that BoDV-1 enters the central nervous system (CNS) via the olfactory pathway. However, (I) susceptible cell types that replicate the virus for successful spread, and (II) the role of olfactory ensheathing cells (OECs), remained unclear. To address this, we studied the intranasal infection of adult rats with BoDV-1 in vivo and in vitro, using olfactory mucosal (OM) cell cultures and the cultures of purified OECs. Strikingly, in vitro and in vivo, viral antigen and mRNA were present from four days post infection (dpi) onwards in the olfactory receptor neurons (ORNs), but also in all other cell types of the OM, and constantly in the OECs. In contrast, in vivo, BoDV-1 genomic RNA was only detectable in adult and juvenile ORNs, nerve fibers, and in OECs from 7 dpi on. In vitro, the rate of infection of OECs was significantly higher than that of the OM cells, pointing to a crucial role of OECs for infection via the olfactory pathway. Thus, this study provides important insights into the transmission of neurotropic viral infections with a zoonotic potential.

Protective Efficacy of Recombinant Modified Vaccinia Virus Ankara Delivering Middle East Respiratory Syndrome Coronavirus Spike Glycoprotein.

Middle East respiratory syndrome coronavirus (MERS-CoV) causes severe respiratory disease in humans. We tested a recombinant modified vaccinia virus Ankara (MVA) vaccine expressing full-length MERS-CoV spike (S) glycoprotein by immunizing BALB/c mice with either intramuscular or subcutaneous regimens. In all cases, MVA-MERS-S induced MERS-CoV-specific CD8(+) T cells and virus-neutralizing antibodies. Vaccinated mice were protected against MERS-CoV challenge infection after transduction with the human dipeptidyl peptidase 4 receptor. This MERS-CoV infection model demonstrates the safety and efficacy of the candidate vaccine.

A Highly Immunogenic and Protective Middle East Respiratory Syndrome Coronavirus Vaccine Based on a Recombinant Measles Virus Vaccine Platform.

UNLABELLED: In 2012, the first cases of infection with the Middle East respiratory syndrome coronavirus (MERS-CoV) were identified. Since then, more than 1,000 cases of MERS-CoV infection have been confirmed; infection is typically associated with considerable morbidity and, in approximately 30% of cases, mortality. Currently, there is no protective vaccine available. Replication-competent recombinant measles virus (MV) expressing foreign antigens constitutes a promising tool to induce protective immunity against corresponding pathogens. Therefore, we generated MVs expressing the spike glycoprotein of MERS-CoV in its full-length (MERS-S) or a truncated, soluble variant of MERS-S (MERS-solS). The genes encoding MERS-S and MERS-solS were cloned into the vaccine strain MVvac2 genome, and the respective viruses were rescued (MVvac2-CoV-S and MVvac2-CoV-solS). These recombinant MVs were amplified and characterized at passages 3 and 10. The replication of MVvac2-CoV-S in Vero cells turned out to be comparable to that of the control virus MVvac2-GFP (encoding green fluorescent protein), while titers of MVvac2-CoV-solS were impaired approximately 3-fold. The genomic stability and expression of the inserted antigens were confirmed via sequencing of viral cDNA and immunoblot analysis. In vivo, immunization of type I interferon receptor-deficient (IFNAR(-/-))-CD46Ge mice with 2 × 10(5) 50% tissue culture infective doses of MVvac2-CoV-S(H) or MVvac2-CoV-solS(H) in a prime-boost regimen induced robust levels of both MV- and MERS-CoV-neutralizing antibodies. Additionally, induction of specific T cells was demonstrated by T cell proliferation, antigen-specific T cell cytotoxicity, and gamma interferon secretion after stimulation of splenocytes with MERS-CoV-S presented by murine dendritic cells. MERS-CoV challenge experiments indicated the protective capacity of these immune responses in vaccinated mice. IMPORTANCE: Although MERS-CoV has not yet acquired extensive distribution, being mainly confined to the Arabic and Korean peninsulas, it could adapt to spread more readily among humans and thereby become pandemic. Therefore, the development of a vaccine is mandatory. The integration of antigen-coding genes into recombinant MV resulting in coexpression of MV and foreign antigens can efficiently be achieved. Thus, in combination with the excellent safety profile of the MV vaccine, recombinant MV seems to constitute an ideal vaccine platform. The present study shows that a recombinant MV expressing MERS-S is genetically stable and induces strong humoral and cellular immunity against MERS-CoV in vaccinated mice. Subsequent challenge experiments indicated protection of vaccinated animals, illustrating the potential of MV as a vaccine platform with the potential to target emerging infections, such as MERS-CoV.

T-bet+ B cells are activated by and control endogenous retroviruses through TLR-dependent mechanisms.

Endogenous retroviruses (ERVs) are an integral part of the mammalian genome. The role of immune control of ERVs in general is poorly defined as is their function as anti-cancer immune targets or drivers of autoimmune disease. Here, we generate mouse-strains where Moloney-Murine Leukemia Virus tagged with GFP (ERV-GFP) infected the mouse germline. This enables us to analyze the role of genetic, epigenetic and cell intrinsic restriction factors in ERV activation and control. We identify an autoreactive B cell response against the neo-self/ERV antigen GFP as a key mechanism of ERV control. Hallmarks of this response are spontaneous ERV-GFP+ germinal center formation, elevated serum IFN-γ levels and a dependency on Age-associated B cells (ABCs) a subclass of T-bet+ memory B cells. Impairment of IgM B cell receptor-signal in nucleic-acid sensing TLR-deficient mice contributes to defective ERV control. Although ERVs are a part of the genome they break immune tolerance, induce immune surveillance against ERV-derived self-antigens and shape the host immune response.

Short- and Long-Interval Prime-Boost Vaccination with the Candidate Vaccines MVA-SARS-2-ST and MVA-SARS-2-S Induces Comparable Humoral and Cell-Mediated Immunity in Mice.

The COVID-19 pandemic caused significant human health and economic consequences. Due to the ability of SARS-CoV-2 to spread rapidly and to cause severe disease and mortality in certain population groups, vaccines are essential for controlling the pandemic in the future. Several licensed vaccines have shown improved protection against SARS-CoV-2 after extended-interval prime-boost immunizations in humans. Therefore, in this study, we aimed to compare the immunogenicity of our two Modified Vaccinia virus Ankara (MVA) based COVID-19 candidate vaccines MVA-SARS-2-S and MVA-SARS-2-ST after short- and long-interval prime-boost immunization schedules in mice. We immunized BALB/c mice using 21-day (short-interval) or 56-day (long-interval) prime-boost vaccination protocols and analyzed spike (S)-specific CD8 T cell immunity and humoral immunity. The two schedules induced robust CD8 T cell responses with no significant differences in their magnitude. Furthermore, both candidate vaccines induced comparable levels of total S, and S2-specific IgG binding antibodies. However, MVA-SARS-2-ST consistently elicited higher amounts of S1-, S receptor binding domain (RBD), and SARS-CoV-2 neutralizing antibodies in both vaccination protocols. Overall, we found very comparable immune responses following short- or long-interval immunization. Thus, our results suggest that the chosen time intervals may not be suitable to observe potential differences in antigen-specific immunity when testing different prime-boost intervals with our candidate vaccines in the mouse model. Despite this, our data clearly showed that MVA-SARS-2-ST induced superior humoral immune responses relative to MVA-SARS-2-S after both immunization schedules.

Protective CD8+ T Cell Response Induced by Modified Vaccinia Virus Ankara Delivering Ebola Virus Nucleoprotein.

The urgent need for vaccines against Ebola virus (EBOV) was underscored by the large outbreak in West Africa (2014-2016). Since then, several promising vaccine candidates have been tested in pre-clinical and clinical studies. As a result, two vaccines were approved for human use in 2019/2020, of which one includes a heterologous adenovirus/Modified Vaccinia virus Ankara (MVA) prime-boost regimen. Here, we tested new vaccine candidates based on the recombinant MVA vector, encoding the EBOV nucleoprotein (MVA-EBOV-NP) or glycoprotein (MVA-EBOV-GP) for their efficacy after homologous prime-boost immunization in mice. Our aim was to investigate the role of each antigen in terms of efficacy and correlates of protection. Sera of mice vaccinated with MVA-EBOV-GP were virus-neutralizing and MVA-EBOV-NP immunization readily elicited interferon-γ-producing NP-specific CD8+ T cells. While mock-vaccinated mice succumbed to EBOV infection, all vaccinated mice survived and showed drastically decreased viral loads in sera and organs. In addition, MVA-EBOV-NP vaccinated mice became susceptible to lethal EBOV infection after depletion of CD8+ T cells prior to challenge. This study highlights the potential of MVA-based vaccines to elicit humoral immune responses as well as a strong and protective CD8+ T cell response and contributes to understanding the possible underlying mechanisms.

Increased neutralization and IgG epitope identification after MVA-MERS-S booster vaccination against Middle East respiratory syndrome.

Vaccine development is essential for pandemic preparedness. We previously conducted a Phase 1 clinical trial of the vector vaccine candidate MVA-MERS-S against the Middle East respiratory syndrome coronavirus (MERS-CoV), expressing its full spike glycoprotein (MERS-CoV-S), as a homologous two-dose regimen (Days 0 and 28). Here, we evaluate the safety (primary objective) and immunogenicity (secondary and exploratory objectives: magnitude and characterization of vaccine-induced humoral responses) of a third vaccination with MVA-MERS-S in a subgroup of trial participants one year after primary immunization. MVA-MERS-S booster vaccination is safe and well-tolerated. Both binding and neutralizing anti-MERS-CoV antibody titers increase substantially in all participants and exceed maximum titers observed after primary immunization more than 10-fold. We identify four immunogenic IgG epitopes, located in the receptor-binding domain (RBD, n = 1) and the S2 subunit (n = 3) of MERS-CoV-S. The level of baseline anti-human coronavirus antibody titers does not impact the generation of anti-MERS-CoV antibody responses. Our data support the rationale of a booster vaccination with MVA-MERS-S and encourage further investigation in larger trials. Trial registration: Clinicaltrials.gov NCT03615911.

Vaccine-associated enhanced respiratory pathology in COVID-19 hamsters after TH2-biased immunization.

Vaccine-associated enhanced respiratory disease (VAERD) is a severe complication for some respiratory infections. To investigate the potential for VAERD induction in coronavirus disease 2019 (COVID-19), we evaluate two vaccine leads utilizing a severe hamster infection model: a T helper type 1 (TH1)-biased measles vaccine-derived candidate and a TH2-biased alum-adjuvanted, non-stabilized spike protein. The measles virus (MeV)-derived vaccine protects the animals, but the protein lead induces VAERD, which can be alleviated by dexamethasone treatment. Bulk transcriptomic analysis reveals that our protein vaccine prepares enhanced host gene dysregulation in the lung, exclusively up-regulating mRNAs encoding the eosinophil attractant CCL-11, TH2-driving interleukin (IL)-19, or TH2 cytokines IL-4, IL-5, and IL-13. Single-cell RNA sequencing (scRNA-seq) identifies lung macrophages or lymphoid cells as sources, respectively. Our findings imply that VAERD is caused by the concerted action of hyperstimulated macrophages and TH2 cytokine-secreting lymphoid cells and potentially links VAERD to antibody-dependent enhancement (ADE). In summary, we identify the cytokine drivers and cellular contributors that mediate VAERD after TH2-biased vaccination.

Stabilized recombinant SARS-CoV-2 spike antigen enhances vaccine immunogenicity and protective capacity.

The SARS-CoV-2 spike (S) glycoprotein is synthesized as a large precursor protein and must be activated by proteolytic cleavage into S1 and S2. A recombinant modified vaccinia virus Ankara (MVA) expressing native, full-length S protein (MVA-SARS-2-S) is currently under investigation as a candidate vaccine in phase I clinical studies. Initial results from immunogenicity monitoring revealed induction of S-specific antibodies binding to S2, but low-level antibody responses to the S1 domain. Follow-up investigations of native S antigen synthesis in MVA-SARS-2-S-infected cells revealed limited levels of S1 protein on the cell surface. In contrast, we found superior S1 cell surface presentation upon infection with a recombinant MVA expressing a stabilized version of SARS-CoV-2 S protein with an inactivated S1/S2 cleavage site and K986P and V987P mutations (MVA-SARS-2-ST). When comparing immunogenicity of MVA vector vaccines, mice vaccinated with MVA-SARS-2-ST mounted substantial levels of broadly reactive anti-S antibodies that effectively neutralized different SARS-CoV-2 variants. Importantly, intramuscular MVA-SARS-2-ST immunization of hamsters and mice resulted in potent immune responses upon challenge infection and protected from disease and severe lung pathology. Our results suggest that MVA-SARS-2-ST represents an improved clinical candidate vaccine and that the presence of plasma membrane-bound S1 is highly beneficial to induce protective antibody levels.

Development and characterization of an indirect ELISA to detect SARS-CoV-2 spike protein-specific antibodies.

The current Severe acute respiratory syndrome-related coronavirus 2 (SARS-CoV-2) pandemic is a public health emergency of international concern. Sensitive and precise diagnostic tools are urgently needed. In this study, we developed a SARS-CoV-2 spike (S1) protein enzyme-linked immunosorbent assay (ELISA) to detect SARS-CoV-2-specific antibodies. The SARS-CoV-2 S1 ELISA was found to be specific [97.8% (95% CI, 96.7% - 98.5%)], reproducible and precise (intra-assay coefficient of variability (CV) 5.3%, inter-assay CV 7.9%). A standard curve and the interpolation of arbitrary ELISA units per milliliter served to reduce the variability between different tests and operators. Cross-reactivity to other human coronaviruses was addressed by using sera positive for MERS-CoV- and hCoV HKU1-specific antibodies. Monitoring antibody development in various samples of twenty-three and single samples of twenty-nine coronavirus disease 2019 (COVID-19) patients revealed seroconversion and neutralizing antibodies against authentic SARS-CoV-2 in all cases. The comparison of the SARS-CoV-2 (S1) ELISA with a commercially available assay showed a better sensitivity for the in-house ELISA. The results demonstrate a high reproducibility, specificity and sensitivity of the newly developed ELISA, which is suitable for the detection of SARS-CoV-2 S1 protein-specific antibody responses.

Post-viral effects of COVID-19 in the olfactory system and their implications.

BACKGROUND: The mechanisms by which any upper respiratory virus, including SARS-CoV-2, impairs chemosensory function are not known. COVID-19 is frequently associated with olfactory dysfunction after viral infection, which provides a research opportunity to evaluate the natural course of this neurological finding. Clinical trials and prospective and histological studies of new-onset post-viral olfactory dysfunction have been limited by small sample sizes and a paucity of advanced neuroimaging data and neuropathological samples. Although data from neuropathological specimens are now available, neuroimaging of the olfactory system during the acute phase of infection is still rare due to infection control concerns and critical illness and represents a substantial gap in knowledge. RECENT DEVELOPMENTS: The active replication of SARS-CoV-2 within the brain parenchyma (ie, in neurons and glia) has not been proven. Nevertheless, post-viral olfactory dysfunction can be viewed as a focal neurological deficit in patients with COVID-19. Evidence is also sparse for a direct causal relation between SARS-CoV-2 infection and abnormal brain findings at autopsy, and for trans-synaptic spread of the virus from the olfactory epithelium to the olfactory bulb. Taken together, clinical, radiological, histological, ultrastructural, and molecular data implicate inflammation, with or without infection, in either the olfactory epithelium, the olfactory bulb, or both. This inflammation leads to persistent olfactory deficits in a subset of people who have recovered from COVID-19. Neuroimaging has revealed localised inflammation in intracranial olfactory structures. To date, histopathological, ultrastructural, and molecular evidence does not suggest that SARS-CoV-2 is an obligate neuropathogen. WHERE NEXT?: The prevalence of CNS and olfactory bulb pathosis in patients with COVID-19 is not known. We postulate that, in people who have recovered from COVID-19, a chronic, recrudescent, or permanent olfactory deficit could be prognostic for an increased likelihood of neurological sequelae or neurodegenerative disorders in the long term. An inflammatory stimulus from the nasal olfactory epithelium to the olfactory bulbs and connected brain regions might accelerate pathological processes and symptomatic progression of neurodegenerative disease. Persistent olfactory impairment with or without perceptual distortions (ie, parosmias or phantosmias) after SARS-CoV-2 infection could, therefore, serve as a marker to identify people with an increased long-term risk of neurological disease.

Intranasal Administration of a Monoclonal Neutralizing Antibody Protects Mice against SARS-CoV-2 Infection.

Despite the recent availability of vaccines against severe acute respiratory syndrome coronavirus type 2 (SARS-CoV-2), there is an urgent need for specific anti-SARS-CoV-2 drugs. Monoclonal neutralizing antibodies are an important drug class in the global fight against the SARS-CoV-2 pandemic due to their ability to convey immediate protection and their potential to be used as both prophylactic and therapeutic drugs. Clinically used neutralizing antibodies against respiratory viruses are currently injected intravenously, which can lead to suboptimal pulmonary bioavailability and thus to a lower effectiveness. Here we describe DZIF-10c, a fully human monoclonal neutralizing antibody that binds the receptor-binding domain of the SARS-CoV-2 spike protein. DZIF-10c displays an exceptionally high neutralizing potency against SARS-CoV-2, retains full activity against the variant of concern (VOC) B.1.1.7 and still neutralizes the VOC B.1.351, although with reduced potency. Importantly, not only systemic but also intranasal application of DZIF-10c abolished the presence of infectious particles in the lungs of SARS-CoV-2 infected mice and mitigated lung pathology when administered prophylactically. Along with a favorable pharmacokinetic profile, these results highlight DZIF-10c as a novel human SARS-CoV-2 neutralizing antibody with high in vitro and in vivo antiviral potency. The successful intranasal application of DZIF-10c paves the way for clinical trials investigating topical delivery of anti-SARS-CoV-2 antibodies.

Osteogenesis imperfecta in a male holstein calf associated with a possible oligogenic origin.

Background: Neuromusculoskeletal anomalies generally in combination with severe clinical symptoms, comprise a heterogeneous group of fairly common and mostly fatal disorders in man and animals. Osteogenesis imperfecta (OI), also known as brittle bone disease, causes bone fragility and deformity. Prominent extra-skeletal accessory manifestations of OI comprise blue/gray sclerae, hearing impairment, lung abnormalities and hypercalciuria. Cases of OI in cattle have been reported. However, no causative mutations have been identified in cattle so far.Aim: To report a possible oligogenic origin identified in a calf from clinically healthy parents suffering from OI.Materials and Methods: A neonatal embryo transfer male Holstein calf developing multiple fractures with bone tissue showing marked osteopenia was used for whole genome re-sequencing as well as its parents. In addition, 2,612 randomly chosen healthy Holstein cattle were genotyped as well as controls.Results: Sixteen candidate genes with potential protein-altering variants were selected revealing non-synonymous variants only within IFITM5 and CRTAP genes. However, in-depth gene analysis did not result in the identification of a single causative mutation in the OI calf.Conclusion: The analysis of the OI case revealed a possible oligogenic origin of the disease attributable to additive effects of three candidate genes, i.e., ABCA13, QRFPR, and IFTIM5.Clinical relevance: Most OI cases in humans and domestic animals reported so far are caused by distinct dominant or recessive monogenic mutations, therefore a potential oligogenic additive genetic effect is a novel finding. Furthermore, the case presented here demonstrates that cross-species genetic analyses might not always be straightforward.

Safety and immunogenicity of a modified vaccinia virus Ankara vector vaccine candidate for Middle East respiratory syndrome: an open-label, phase 1 trial.

BACKGROUND: The Middle East respiratory syndrome coronavirus (MERS-CoV) causes a respiratory disease with a case fatality rate of up to 35%. Given its potential to cause a public health emergency and the absence of efficacious drugs or vaccines, MERS is one of the WHO priority diseases warranting urgent research and development of countermeasures. We aimed to assess safety and tolerability of an anti-MERS-CoV modified vaccinia virus Ankara (MVA)-based vaccine candidate that expresses the MERS-CoV spike glycoprotein, MVA-MERS-S, in healthy adults. METHODS: This open-label, phase 1 trial was done at the University Medical Center Hamburg-Eppendorf (Hamburg, Germany). Participants were healthy men and women aged 18-55 years with no clinically significant health problems as determined during medical history and physical examination, a body-mass index of 18·5-30·0 kg/m2 and weight of more than 50 kg at screening, and a negative pregnancy test for women. A key exclusion criterion was a previous MVA vaccination. For the prime immunisation, participants received doses of 1 × 107 plaque-forming unit (PFU; low-dose group) or 1 × 108 PFU (high-dose group) MVA-MERS-S intramuscularly. A second identical dose was administered intramuscularly as a booster immunisation 28 days after first injection. As a control group for immunogenicity analyses, blood samples were drawn at identical study timepoints from six healthy adults, who did not receive any injections. The primary objectives of the study were safety and tolerability of the two dosage levels and reactogenicity after administration. Immunogenicity was assessed as a secondary endpoint by ELISA and neutralisation tests. T-cell immunity was evaluated by interferon-γ-linked enzyme-linked immune absorbent spot assay. All participants who were vaccinated at least once were included in the safety analysis. Immunogenicity was analysed in the participants who completed 6 months of follow-up. This trial is registered with ClinicalTrials.gov, NCT03615911, and EudraCT, 2014-003195-23 FINDINGS: From Dec 17, 2017, to June 5, 2018, 26 participants (14 in the low-dose group and 12 in the high-dose group) were enrolled and received the first dose of the vaccine according to their group allocation. Of these, 23 participants (12 in the low-dose group and 11 in the high-dose group) received a second dose of MVA-MERS-S according to their group allocation after a 28-day interval and completed follow-up. Homologous prime-boost immunisation with MVA-MERS-S revealed a benign safety profile with only transient mild-to-moderate reactogenicity. Participants had no severe or serious adverse events. 67 vaccine-related adverse events were reported in ten (71%) of 14 participants in the low-dose group, and 111 were reported in ten (83%) of 12 participants in the high-dose group. Solicited local reactions were the most common adverse events: pain was observed in 17 (65%; seven in the low-dose group vs ten in the high-dose group) participants, swelling in ten (38%; two vs eight) participants, and induration in ten (38%; one vs nine) participants. Headaches (observed in seven participants in the low-dose group vs nine in the high-dose group) and fatigue or malaise (ten vs seven participants) were the most common solicited systemic adverse events. All adverse events resolved swiftly (within 1-3 days) and without sequelae. Following booster immunisation, nine (75%) of 12 participants in the low-dose group and 11 (100%) participants in the high-dose group showed seroconversion using a MERS-CoV S1 ELISA at any timepoint during the study. Binding antibody titres correlated with MERS-CoV-specific neutralising antibodies (Spearman's correlation r=0·86 [95% CI 0·6960-0·9427], p=0·0001). MERS-CoV spike-specific T-cell responses were detected in ten (83%) of 12 immunised participants in the low-dose group and ten (91%) of 11 immunised participants in the high-dose group. INTERPRETATION: Vaccination with MVA-MERS-S had a favourable safety profile without serious or severe adverse events. Homologous prime-boost immunisation induced humoral and cell-mediated responses against MERS-CoV. A dose-effect relationship was demonstrated for reactogenicity, but not for vaccine-induced immune responses. The data presented here support further clinical testing of MVA-MERS-S in larger cohorts to advance MERS vaccine development. FUNDING: German Center for Infection Research.