ORCID Profile
0000-0001-6086-9136
Current Organisations
German Primate Center
,
Michigan State University
,
Tsinghua University
,
Hong Kong University of Science and Technology
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Publisher: Springer Science and Business Media LLC
Date: 11-10-2021
Publisher: Springer Science and Business Media LLC
Date: 02-11-2020
DOI: 10.1038/S41423-020-00573-9
Abstract: Neutralizing antibodies targeting the receptor-binding domain (RBD) of the SARS-CoV-2 spike (S) block severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) entry into cells via surface-expressed angiotensin-converting enzyme 2 (ACE2). We used a surrogate virus neutralization test (sVNT) and SARS-CoV-2 S protein-pseudotyped vesicular stomatitis virus (VSV) vector-based neutralization assay (pVNT) to assess the degree to which serum antibodies from coronavirus disease 2019 (COVID-19) convalescent patients interfere with the binding of SARS-CoV-2 S to ACE2. Both tests revealed neutralizing anti-SARS-CoV-2 S antibodies in the sera of ~90% of mildly and 100% of severely affected COVID-19 convalescent patients. Importantly, sVNT and pVNT results correlated strongly with each other and to the levels of anti-SARS-CoV-2 S1 IgG and IgA antibodies. Moreover, levels of neutralizing antibodies correlated with the duration and severity of clinical symptoms but not with patient age. Compared to pVNT, sVNT is less sophisticated and does not require any biosafety labs. Since this assay is also much faster and cheaper, sVNT will not only be important for evaluating the prevalence of neutralizing antibodies in a population but also for identifying promising plasma donors for successful passive antibody therapy.
Publisher: Elsevier BV
Date: 02-2006
Publisher: MDPI AG
Date: 14-11-2022
Abstract: Recently, a recombinant SARS-CoV-2 lineage, XD, emerged that harbors a spike gene that is largely derived from the Omicron variant BA.1 in the genetic background of the Delta variant. This finding raised concerns that the recombinant virus might exhibit altered biological properties as compared to the parental viruses and might pose an elevated threat to human health. Here, using pseudotyped particles, we show that ACE2 binding and cell tropism of XD mimics that of BA.1. Further, XD and BA.1 displayed comparable sensitivity to neutralization by antibodies induced upon vaccination with BNT162b2/Comirnaty (BNT) or BNT vaccination followed by breakthrough infection. Our findings reveal important biological commonalities between XD and Omicron BA.1 host cell entry and its inhibition by antibodies.
Publisher: American Society for Microbiology
Date: 15-05-2013
DOI: 10.1128/JVI.00128-13
Abstract: The novel human coronavirus EMC (hCoV-EMC), which recently emerged in Saudi Arabia, is highly pathogenic and could pose a significant threat to public health. The elucidation of hCoV-EMC interactions with host cells is critical to our understanding of the pathogenesis of this virus and to the identification of targets for antiviral intervention. Here we investigated the viral and cellular determinants governing hCoV-EMC entry into host cells. We found that the spike protein of hCoV-EMC (EMC-S) is incorporated into lentiviral particles and mediates transduction of human cell lines derived from different organs, including the lungs, kidneys, and colon, as well as primary human macrophages. Expression of the known coronavirus receptors ACE2, CD13, and CEACAM1 did not facilitate EMC-S-driven transduction, suggesting that hCoV-EMC uses a novel receptor for entry. Directed protease expression and inhibition analyses revealed that TMPRSS2 and endosomal cathepsins activate EMC-S for virus-cell fusion and constitute potential targets for antiviral intervention. Finally, EMC-S-driven transduction was abrogated by serum from an hCoV-EMC-infected patient, indicating that EMC-S-specific neutralizing antibodies can be generated in patients. Collectively, our results indicate that hCoV-EMC uses a novel receptor for protease-activated entry into human cells and might be capable of extrapulmonary spread. In addition, they define TMPRSS2 and cathepsins B and L as potential targets for intervention and suggest that neutralizing antibodies contribute to the control of hCoV-EMC infection.
Publisher: Springer Science and Business Media LLC
Date: 23-09-2002
DOI: 10.1038/NI841
Publisher: Springer Science and Business Media LLC
Date: 23-08-2021
Publisher: Springer Science and Business Media LLC
Date: 18-08-2022
DOI: 10.1038/S41467-022-32527-2
Abstract: Heterologous prime/boost vaccination with a vector-based approach (ChAdOx-1nCov-19, ChAd) followed by an mRNA vaccine (e.g. BNT162b2, BNT) has been reported to be superior in inducing protective immunity compared to repeated application of the same vaccine. However, data comparing immunity decline after homologous and heterologous vaccination as well as effects of a third vaccine application after heterologous ChAd/BNT vaccination are lacking. Here we show longitudinal monitoring of ChAd/ChAd ( n = 41) and ChAd/BNT ( n = 88) vaccinated in iduals and the impact of a third vaccination with BNT. The third vaccination greatly augments waning anti-spike IgG but results in only moderate increase in spike-specific CD4 + and CD8 + T cell numbers in both groups, compared to cell frequencies already present after the second vaccination in the ChAd/BNT group. More importantly, the third vaccination efficiently restores neutralizing antibody responses against the Alpha, Beta, Gamma, and Delta variants of the virus, but neutralizing activity against the B.1.1.529 (Omicron) variant remains severely impaired. In summary, inferior SARS-CoV-2 specific immune responses following homologous ChAd/ChAd vaccination can be compensated by heterologous BNT vaccination, which might influence the choice of vaccine type for subsequent vaccination boosts.
Publisher: American Society for Microbiology
Date: 09-03-2022
DOI: 10.1128/JVI.02186-21
Abstract: Recently emerging SARS-CoV-2 variants B.1.1.7 (alpha variant), B.1.617.2 (delta variant), and B.1.1.529 (omicron variant) harbor spike mutations and have been linked to increased virus pathogenesis. The emergence of these novel variants highlights coronavirus adaptation and evolution potential, despite the stable consensus genotype of clinical isolates.
Publisher: Springer Science and Business Media LLC
Date: 14-07-2021
DOI: 10.1038/S41591-021-01449-9
Abstract: Currently approved viral vector-based and mRNA-based vaccine approaches against coronavirus disease 2019 (COVID-19) consider only homologous prime-boost vaccination. After reports of thromboembolic events, several European governments recommended using AstraZeneca’s ChAdOx1-nCov-19 (ChAd) only in in iduals older than 60 years, leaving millions of already ChAd-primed in iduals with the decision to receive either a second shot of ChAd or a heterologous boost with mRNA-based vaccines. However, such combinations have not been tested so far. We used Hannover Medical School’s COVID-19 Contact Study cohort of healthcare professionals to monitor ChAd-primed immune responses before and 3 weeks after booster with ChAd ( n = 32) or BioNTech/Pfizer’s BNT162b2 ( n = 55). Although both vaccines boosted prime-induced immunity, BNT162b2 induced significantly higher frequencies of spike-specific CD4 + and CD8 + T cells and, in particular, high titers of neutralizing antibodies against the B.1.1.7, B.1.351 and P.1 variants of concern of severe acute respiratory syndrome coronavirus 2.
Publisher: MDPI AG
Date: 09-11-2022
DOI: 10.3390/V14112475
Abstract: The spike (S) protein of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) facilitates viral entry into host cells and is the key target for neutralizing antibodies. The SARS-CoV-2 lineage B.1.620 carries fifteen mutations in the S protein and is spread in Africa, the US and Europe, while lineage R.1 harbors four mutations in S and infections were observed in several countries, particularly Japan and the US. However, the impact of the mutations in B.1.620 and R.1 S proteins on antibody-mediated neutralization and host cell entry are largely unknown. Here, we report that these mutations are compatible with robust ACE2 binding and entry into cell lines, and they markedly reduce neutralization by vaccine-induced antibodies. Our results reveal evasion of neutralizing antibodies by B.1.620 and R.1, which might have contributed to the spread of these lineages.
Publisher: Springer Science and Business Media LLC
Date: 17-05-2022
Publisher: Oxford University Press (OUP)
Date: 28-03-2006
Publisher: Research Square Platform LLC
Date: 29-12-2021
DOI: 10.21203/RS.3.RS-1200506/V1
Abstract: Reports suggest that COVID-19 vaccine effectiveness is decreasing, either due to waning immune protection, emergence of new variants of concern, or both. Heterologous prime/boost vaccination with a vector-based approach (ChAdOx-1nCov-19, ChAd) followed by an mRNA vaccine (e.g. BNT162b2, BNT) appeared to be superior in inducing protective immunity, and large scale second booster vaccination is ongoing. However, data comparing declining immunity after homologous and heterologous vaccination as well as effects of a third vaccine application after heterologous ChAd/BNT vaccination are lacking. We longitudinally monitored immunity in ChAd/ChAd (n=41) and ChAd/BNT (n=88) vaccinated in iduals and assessed the impact of a second booster with BNT in both groups. The second booster greatly augmented waning anti-spike IgG but only moderately increased spike-specific CD4+ and CD8+ T cells in both groups to cell frequencies already present after the boost. More importantly, the second booster efficiently restored neutralizing antibody responses against Alpha, Beta, Gamma, and Delta, but neutralizing activity against B.1.1.529 (Omicron) stayed severely impaired. Our data suggest that inferior SARS-CoV-2 specific immune responses after homologous ChAd/ChAd vaccination can be cured by a heterologous BNT vaccination. However, prior heterologous ChAd/BNT vaccination provides no additional benefit for spike-specific T cell immunity or neutralizing Omicron after the second boost.
Publisher: Springer Science and Business Media LLC
Date: 08-05-2023
Publisher: Research Square Platform LLC
Date: 03-06-2021
DOI: 10.21203/RS.3.RS-566785/V1
Abstract: Global pandemics by influenza or coronaviruses cause severe disruptions to the public health and lead to severe morbidity and mortality. Vaccines against these pathogens remain a medical need. CMV (cytomegalovirus) is a β-herpesvirus that induces uniquely robust immune responses, where outstandingly large populations of antigen-specific CD8+ T cells are maintained for a lifetime. Hence, CMV has been proposed and investigated as a novel vaccine vector expressing antigenic peptides or proteins to elicit protective cellular immune responses against numerous pathogens. We generated two recombinant murine CMV (MCMV) vaccine vectors expressing the hemagglutinin (HA) of influenza A virus (MCMVHA) or the spike protein of the severe acute respiratory syndrome coronavirus 2 (MCMVS). A single shot of MCMVs expressing either viral protein induced potent neutralizing antibody responses, which strengthened over time. Importantly, MCMVHA vaccinated mice were protected from illness following challenge with the influenza virus, and we excluded that this protection was due to effects of memory T cells. Conclusively, we show here that MCMV vectors do not only induce long-term cellular immunity, but also humoral responses that provide long-term immune protection against clinically relevant respiratory pathogens.
Publisher: Elsevier BV
Date: 05-2019
DOI: 10.1016/J.CELREP.2019.04.063
Abstract: Guanylate-binding protein (GBP) 5 is an interferon (IFN)-inducible cellular factor reducing HIV-1 infectivity by an incompletely understood mechanism. Here, we show that this activity is shared by GBP2, but not by other members of the human GBP family. GBP2/5 decrease the activity of the cellular proprotein convertase furin, which mediates conversion of the HIV-1 envelope protein (Env) precursor gp160 into mature gp120 and gp41. Because this process primes HIV-1 Env for membrane fusion, viral particles produced in the presence of GBP2/5 are poorly infectious due to increased incorporation of non-functional gp160. Furin activity is critical for the processing of envelope glycoproteins of many viral pathogens. Consistently, GBP2/5 also inhibit Zika, measles, and influenza A virus replication and decrease infectivity of viral particles carrying glycoproteins of Marburg and murine leukemia viruses. Collectively, our results show that GPB2/5 exert broad antiviral activity by suppressing the activity of the virus-dependency factor furin.
Publisher: Springer Science and Business Media LLC
Date: 25-10-2021
Publisher: Springer Science and Business Media LLC
Date: 07-01-2022
DOI: 10.1038/S41423-021-00814-5
Abstract: Global pandemics caused by influenza or coronaviruses cause severe disruptions to public health and lead to high morbidity and mortality. There remains a medical need for vaccines against these pathogens. CMV (cytomegalovirus) is a β-herpesvirus that induces uniquely robust immune responses in which remarkably large populations of antigen-specific CD8 + T cells are maintained for a lifetime. Hence, CMV has been proposed and investigated as a novel vaccine vector for expressing antigenic peptides or proteins to elicit protective cellular immune responses against numerous pathogens. We generated two recombinant murine CMV (MCMV) vaccine vectors expressing hemagglutinin (HA) of influenza A virus (MCMV HA ) or the spike protein of severe acute respiratory syndrome coronavirus 2 (MCMV S ). A single injection of MCMVs expressing either viral protein induced potent neutralizing antibody responses, which strengthened over time. Importantly, MCMV HA -vaccinated mice were protected from illness following challenge with the influenza virus, and we excluded that this protection was due to the effects of memory T cells. Conclusively, we show here that MCMV vectors induce not only long-term cellular immunity but also humoral responses that provide long-term immune protection against clinically relevant respiratory pathogens.
Publisher: Public Library of Science (PLoS)
Date: 06-07-2021
DOI: 10.1371/JOURNAL.PMED.1003656
Abstract: The Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) antibody neutralization response and its evasion by emerging viral variants and variant of concern (VOC) are unknown, but critical to understand reinfection risk and breakthrough infection following vaccination. Antibody immunoreactivity against SARS-CoV-2 antigens and Spike variants, inhibition of Spike-driven virus–cell fusion, and infectious SARS-CoV-2 neutralization were characterized in 807 serial s les from 233 reverse transcription polymerase chain reaction (RT-PCR)–confirmed Coronavirus Disease 2019 (COVID-19) in iduals with detailed demographics and followed up to 7 months. A broad and sustained polyantigenic immunoreactivity against SARS-CoV-2 Spike, Membrane, and Nucleocapsid proteins, along with high viral neutralization, was associated with COVID-19 severity. A subgroup of “high responders” maintained high neutralizing responses over time, representing ideal convalescent plasma donors. Antibodies generated against SARS-CoV-2 during the first COVID-19 wave had reduced immunoreactivity and neutralization potency to emerging Spike variants and VOC. Accurate monitoring of SARS-CoV-2 antibody responses would be essential for selection of optimal responders and vaccine monitoring and design.
Publisher: Elsevier BV
Date: 2008
Publisher: Springer Science and Business Media LLC
Date: 03-03-2023
Publisher: Elsevier BV
Date: 10-2021
Publisher: American Chemical Society (ACS)
Date: 17-08-2017
DOI: 10.1021/JACS.7B05104
Publisher: ACM
Date: 09-05-2023
Publisher: ACM
Date: 18-06-2023
Publisher: Cold Spring Harbor Laboratory
Date: 05-05-2021
DOI: 10.1101/2021.05.04.442663
Abstract: The emergence of SARS-CoV-2 variants threatens efforts to contain the COVID-19 pandemic. The number of COVID-19 cases and deaths in India has risen steeply in recent weeks and a novel SARS-CoV-2 variant, B.1.617, is believed to be responsible for many of these cases. The spike protein of B.1.617 harbors two mutations in the receptor binding domain, which interacts with the ACE2 receptor and constitutes the main target of neutralizing antibodies. Therefore, we analyzed whether B.1.617 is more adept in entering cells and/or evades antibody responses. B.1.617 entered two out of eight cell lines tested with slightly increased efficiency and was blocked by entry inhibitors. In contrast, B.1.617 was resistant against Bamlanivimab, an antibody used for COVID-19 treatment. Finally, B.1.617 evaded antibodies induced by infection or vaccination, although with moderate efficiency. Collectively, our study reveals that antibody evasion of B.1.617 may contribute to the rapid spread of this variant.
No related grants have been discovered for Stefan Pöhlmann.