scholarly journals Human neutralizing antibodies for SARS-CoV-2 prevention and immunotherapy

2021 ◽  
Author(s):  
Dongyan Zhou ◽  
Runhong Zhou ◽  
Zhiwei Chen
Keyword(s):  
Severe Acute Respiratory Syndrome ◽  
Neutralizing Antibodies ◽  
Immune Escape ◽  
Passive Immunization ◽  
Clinical Development ◽  
Vaccine Research ◽  
Breakthrough Infection ◽  
Clinical Benefits

Abstract Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is the causative agent of coronavirus disease 2019 (COVID-19). SARS-CoV-2 has been spreading worldwide since December 2019, resulting in the ongoing COVID-19 pandemic with 237 million infections and 4.8 million deaths by 11 October 2021. While there are great efforts of global vaccination, ending this pandemic has been challenged by issues of exceptionally high viral transmissibility, re-infection, vaccine-breakthrough infection, and immune escape variants of concerns. Besides the record-breaking speed of vaccine research and development, antiviral drugs including SARS-CoV-2-specific human neutralizing antibodies (HuNAbs) have been actively explored for passive immunization. In support of HuNAb-based immunotherapy, passive immunization using convalescent patients’ plasma have generated promising evidence on clinical benefits for both mild and severe COVID-19 patients. Since the source of convalescent plasma is limited, the discovery of broadly reactive HuNAbs may have significant impacts on the fight against the COVID-19 pandemic. In this review, therefore, we discuss the current technologies of gene cloning, modes of action, in vitro and in vivo potency and breadth, and clinical development for potent SARS-CoV-2-specific HuNAbs.

scholarly journals Murine monoclonal antibodies against RBD of SARS-CoV-2 neutralize authentic wild type SARS-CoV-2 as well as B.1.1.7 and B.1.351 viruses and protect in vivo in a mouse model in a neutralization dependent manner

2021 ◽  
Author(s):  
Fatima Amanat ◽  
Shirin Strohmeier ◽  
Wen-Hsin Lee ◽  
Sandhya Bangaru ◽  
Andrew B Ward ◽  
...  
Keyword(s):  
Monoclonal Antibodies ◽  
Severe Acute Respiratory Syndrome ◽  
Mouse Model ◽  
Neutralizing Antibodies ◽  
Dependent Manner ◽  
Receptor Binding Domain ◽  
Wild Type ◽  
Murine Monoclonal Antibodies

After first emerging in December 2019 in China, severe acute respiratory syndrome 2 (SARS-CoV-2) has since caused a pandemic leading to millions of infections and deaths worldwide. Vaccines have been developed and authorized but supply of these vaccines is currently limited. With new variants of the virus now emerging and spreading globally, it is essential to develop therapeutics that are broadly protective and bind conserved epitopes in the receptor binding domain (RBD) or the whole spike of SARS-CoV-2. In this study, we have generated mouse monoclonal antibodies (mAbs) against different epitopes on the RBD and assessed binding and neutralization against authentic SARS-CoV-2. We have demonstrated that antibodies with neutralizing activity, but not non-neutralizing antibodies, lower viral titers in the lungs when administered in a prophylactic setting in vivo in a mouse challenge model. In addition, most of the mAbs cross-neutralize the B.1.351 as well as the B.1.1.7 variants in vitro.

Abstract MP165: Exosome-mediated Encapsulation Alters AAV Antigenicity and Infectivity: Implications for Gene Delivery in the Heart

2020 ◽  
Vol 127 (Suppl_1) ◽  
Author(s):  
Marta Adamiak ◽  
Yaxuan Liang ◽  
Cherrie Sherman ◽  
Shweta Lodha ◽  
Erik Kohlbrenner ◽  
...  
Keyword(s):  
Gene Therapy ◽  
Gene Delivery ◽  
Cardiac Function ◽  
Neutralizing Antibodies ◽  
Firefly Luciferase ◽  
Interferometric Imaging ◽  
Human Cardiomyocytes ◽  
Clinical Benefits

Gene therapy is a promising approach for the treatment of cardiovascular disease. Current strategies for myocardial gene transfer include the use of adeno-associated virus (AAV) vectors. However, AAVs may not be ideal for gene therapy vectors owing to pre-existing AAV capsid immunity in the human population that may reduce transduction efficacy and hinder preclinical-to-clinical translation. Interestingly, recent studies suggest that exosome-mediated encapsulation may protect viruses from neutralizing antibodies (NAbs) against the capsid and promote viral infectivity. Here, we describe the ability of exosome-enveloped AAVs, i.e. exosomal AAVs (eAAVs), to evade NAbs and serve as a highly efficient gene delivery tool for cardiovascular therapeutics. We have developed a method to purifiy eAAVs from AAV-producing HEK-293T cells, and used electron/confocal microscopy, qPCR, immunoblotting, dynamic light scattering and interferometric imaging measurements to characterize eAAV morphology, contents and mechanism of action. We confirmed eAAVs represent vesicular fractions that exhibit common exosome phenotype, along with the presence of virus particles, and demonstrated that eAAV infectious entry potentially involves trafficking via endocytic compartments. Using flow cytometry, Langendorff perfusion system and bioluminescence imaging, we then evaluated efficiency of heart targeting for eAAV9/eAAV6 and standard AAV9/AAV6 encoding for mCherry or firefly luciferase in human cardiomyocytes in vitro and in mouse model in vivo . Regardless of the presence or absence of NAbs, we showed that eAAVs are more efficient in transduction in the same titer ranges as compared to standard AAVs. To test therapeutic efficacy, we intramyocardially injected eAAV9 or AAV9 vectors encoding for SERCA2a in NAb+ post-myocardial infarction mice and further evaluated cardiac function using echocardiography. Remarkably, eAAV9-SERCA2a outperformed standard AAVs significantly improving cardiac function in the presence of NAbs (%EF 55.14 ± 3.50 compared to 27.31 ± 1.63 at 6 weeks, respectively). In summary, delivery of AAVs protected by carrier exosomes (i.e. eAAVs) may retain the clinical benefits of AAVs while addressing one of its major challenges.

scholarly journals Influenza prevention and treatment by passive immunization.

2014 ◽  
Vol 61 (3) ◽  
Author(s):  
Barbara Kalenik ◽  
Róża Sawicka ◽  
Anna Góra-Sochacka ◽  
Agnieszka Sirko
Keyword(s):  
Neutralizing Antibodies ◽  
Passive Immunization ◽  
Egg Yolk ◽  
Passive Immunity ◽  
Protective Effects ◽  
In Vivo Experiments ◽  
Effective Care ◽  
Antibody Preparations

Passive immunity is defined as a particular antigen resistance provided by external antibodies. It can be either naturally or artificially acquired. Natural passive immunization occurs during pregnancy and breast-feeding in mammals and during hatching in birds. Maternal antibodies are passed through the placenta and milk in mammals and through the egg yolk in birds. Artificial passive immunity is acquired by injection of either serum from immunized (or infected) individuals or antibody preparations. Many independent research groups worked on selection, verification and detailed characterization of polyclonal and monoclonal antibodies against the influenza virus. Numerous antibody preparations were tested in a variety of in vitro and in vivo experiments for their efficacy to neutralize the virus. Here, we describe types of antibodies tested in such experiments and their viral targets, review approaches resulting in identification of broadly neutralizing antibodies and discuss methods used to demonstrate their protective effects. Finally, we shortly discuss the phenomenon of maternal antibody transfer as a way of effective care for young individuals and as an interfering factor in early vaccination.

scholarly journals A Chlamydia trachomatis VD1-MOMP vaccine elicits cross-neutralizing and protective antibodies against C/C-related complex serovars

npj Vaccines ◽  
2021 ◽  
Vol 6 (1) ◽  
Author(s):  
Anja Weinreich Olsen ◽  
Ida Rosenkrands ◽  
Martin J. Holland ◽  
Peter Andersen ◽  
Frank Follmann
Keyword(s):  
Chlamydia Trachomatis ◽  
Neutralizing Antibodies ◽  
Biological Effects ◽  
Clinical Development ◽  
B Cell Epitopes ◽  
Urogenital Infections ◽  
Protective Antibodies ◽  
Related Complex

AbstractOcular and urogenital infections with Chlamydia trachomatis (C.t.) are caused by a range of different serovars. The first C.t. vaccine in clinical development (CTH522/CAF®01) induced neutralizing antibodies directed to the variable domain 4 (VD4) region of major outer membrane protein (MOMP), covering predominantly B and intermediate groups of serovars. The VD1 region of MOMP contains neutralizing B-cell epitopes targeting serovars of the C and C-related complex. Using an immuno-repeat strategy, we extended the VD1 region of SvA and SvJ to include surrounding conserved segments, extVD1A and extVD1J, and repeated this region four times. The extVD1A*4 was most immunogenic with broad cross-surface and neutralizing reactivity against representative members of the C and C-related complex serovars. Importantly, in vitro results for extVD1A*4 translated into in vivo biological effects, demonstrated by in vivo neutralization of SvA and protection/cross-protection against intravaginal challenge with both SvA and the heterologous SvIa strain.

scholarly journals New SHIVs and Improved Design Strategy for Modeling HIV-1 Transmission, Immunopathogenesis, Prevention and Cure

2021 ◽  
Author(s):  
Hui Li ◽  
Shuyi Wang ◽  
Fang-Hua Lee ◽  
Ryan S. Roark ◽  
Alex I. Murphy ◽  
...  
Keyword(s):  
T Cells ◽  
Neutralizing Antibodies ◽  
Large Scale ◽  
Rhesus Macaques ◽  
Passive Immunization ◽  
Design Strategy ◽  
Efficient Replication ◽  
Hiv 1

Previously, we showed that substitution of HIV-1 Env residue 375-Ser by bulky aromatic residues enhances binding to rhesus CD4 and enables primary HIV-1 Envs to support efficient replication as simian-human immunodeficiency virus (SHIV) chimeras in rhesus macaques (RMs). Here, we test this design strategy more broadly by constructing SHIVs containing ten primary Envs corresponding to HIV-1 subtypes A, B, C, AE and AG. All ten SHIVs bearing wildtype Env375 residues replicated efficiently in human CD4+ T cells, but only one replicated efficiently in primary rhesus cells. This was a subtype AE SHIV that naturally contained His at Env375. Replacement of wildtype Env375 residues by Trp, Tyr, Phe or His in the other nine SHIVs led to efficient replication in rhesus CD4+ T cells in vitro and in vivo. Nine SHIVs containing optimized Env375 alleles were grown large-scale in primary rhesus CD4+ T cells to serve as challenge stocks in preclinical prevention trials. These virus stocks were genetically homogeneous, native-like in Env antigenicity and tier-2 neutralization sensitivity, and transmissible by rectal, vaginal, penile, oral or intravenous routes. To facilitate future SHIV constructions, we engineered a simplified second-generation design scheme and validated it in RMs. Overall, our findings demonstrate that SHIVs bearing primary Envs with bulky aromatic substitutions at Env375 consistently replicate in RMs, recapitulating many features of HIV-1 infection in humans. Such SHIVs are efficiently transmitted by mucosal routes common to HIV-1 infection and can be used to test vaccine efficacy in preclinical monkey trials. Importance SHIV infection of Indian rhesus macaques is an important animal model for studying HIV-1 transmission, prevention, immunopathogenesis and cure. Such research is timely, given recent progress with active and passive immunization and novel approaches to HIV-1 cure. Given the multifaceted roles of HIV-1 Env in cell tropism and virus entry, and as a target for neutralizing and non-neutralizing antibodies, Envs selected for SHIV construction are of paramount importance. Until recently, it has been impossible to strategically design SHIVs bearing clinically relevant Envs that replicate consistently in monkeys. This changed with the discovery that bulky aromatic substitutions at residue Env375 confer enhanced affinity to rhesus CD4. Here, we show that 10 new SHIVs bearing primary HIV-1 Envs with residue 375 substitutions replicated efficiently in RMs and could be transmitted efficiently across rectal, vaginal, penile and oral mucosa. These findings suggest an expanded role for SHIVs as a model of HIV-1 infection.

scholarly journals Semen-Derived Exosomes Mediate Immune Escape and Transmission of Reticuloendotheliosis Virus

2021 ◽  
Vol 12 ◽  
Author(s):  
Qi Su ◽  
Yawen Zhang ◽  
Zhizhong Cui ◽  
Shuang Chang ◽  
Peng Zhao
Keyword(s):  
Neutralizing Antibodies ◽  
Immune Escape ◽  
Virus Transmission ◽  
Reticuloendotheliosis Virus ◽  
Viral Shedding ◽  
Reverse Transcription Pcr ◽  
Viral Genomic Rna

Reticuloendotheliosis virus (REV) causes immune-suppression disease in poultry, leading to a significant economic burden worldwide. Recent evidence demonstrated that the REV can enter the semen and then induce artificial insemination, but how the virus gets into semen was little known. Accumulating studies indicated that exosomes serve as vehicles for virus transmission, but the role of exosomes in viral shedding through the semen remains unclear. In this study, exosomes purified from the REV-positive semen were shown with reverse transcription-PCR and mass spectrometry to contain viral genomic RNA and viral proteins, which could also establish productive infections both in vivo and in vitro and escape from the REV-specific neutralizing antibodies. More importantly, compared with the infection caused by free virions, the exosome is more efficient for the virus to ensure effective infection and replication, which can also help the REV compromise the efficacy of the host immune response. In summary, this study demonstrated that semen-derived exosomes can medicate the transmission and immune escape of REV, implicating a novel mechanism for REV entering the semen and leading to vertical transmission.

scholarly journals In Vivo and In Vitro Escape from Neutralizing Antibodies 2G12, 2F5, and 4E10

2007 ◽  
Vol 81 (16) ◽  
pp. 8793-8808 ◽  
Author(s):  
Amapola Manrique ◽  
Peter Rusert ◽  
Beda Joos ◽  
Marek Fischer ◽  
Herbert Kuster ◽  
...  
Keyword(s):  
Neutralizing Antibodies ◽  
In Vitro Selection ◽  
Passive Immunization ◽  
Resistance Mutations ◽  
Antibody Treatment ◽  
Glycosylation Sites ◽  
Depth Analysis ◽  
Immunodeficiency Virus

ABSTRACT Recently, passive immunization of human immunodeficiency virus (HIV)-infected individuals with monoclonal antibodies (MAbs) 2G12, 2F5, and 4E10 provided evidence of the in vivo activity of 2G12 but raised concerns about the function of the two membrane-proximal external region (MPER)-specific MAbs (A. Trkola, H. Kuster, P. Rusert, B. Joos, M. Fischer, C. Leemann, A. Manrique, M. Huber, M. Rehr, A. Oxenius, R. Weber, G. Stiegler, B. Vcelar, H. Katinger, L. Aceto, and H. F. Gunthard, Nat. Med. 11:615-622, 2005). In the light of MPER-targeting vaccines under development, we performed an in-depth analysis of the emergence of mutations conferring resistance to these three MAbs to further elucidate their activity. Clonal analysis of the MPER of plasma virus samples derived during antibody treatment confirmed that no changes in this region had occurred in vivo. Sequence analysis of the 2G12 epitope relevant N-glycosylation sites of viruses derived from 13 patients during the trial supported the phenotypic evaluation, demonstrating that mutations in these sites are associated with resistance. In vitro selection experiments with isolates of four of these individuals corroborated the in vivo finding that virus strains rapidly escape 2G12 pressure. Notably, in vitro resistance mutations differed, in most cases, from those found in vivo. Importantly, in vitro selection with 2F5 and 4E10 demonstrated that resistance to these MAbs can be difficult to achieve and can lead to selection of variants with impaired infectivity. This remarkable vulnerability of the virus to interference within the MPER calls for a further evaluation of the safety and efficacy of MPER-targeting therapeutic and vaccination strategies.

scholarly journals Characterization of an In Vivo Neutralizing Anti-Vaccinia Virus D8 Single-Chain Fragment Variable (scFv) from a Human Anti-Vaccinia Virus-Specific Recombinant Library

Vaccines ◽  
2021 ◽  
Vol 9 (11) ◽  
pp. 1308
Author(s):  
Ulrike S. Diesterbeck ◽  
Henrike P. Ahsendorf ◽  
André Frenzel ◽  
Ahmad Reza Sharifi ◽  
Thomas Schirrmann ◽  
...  
Keyword(s):  
Vaccinia Virus ◽  
Neutralizing Antibodies ◽  
Passive Immunization ◽  
Nmri Mouse ◽  
Single Chain ◽  
Single Chain Fragment Variable ◽  
Human Scfv ◽  
Human Immune Response

A panel of potent neutralizing antibodies are protective against orthopoxvirus (OPXV) infections. For the development of OPXV-specific recombinant human single-chain antibodies (scFvs), the IgG repertoire of four vaccinated donors was amplified from peripheral B-lymphocytes. The resulting library consisted of ≥4 × 108 independent colonies. The immuno-screening against vaccinia virus (VACV) Elstree revealed a predominant selection of scFv clones specifically binding to the D8 protein. The scFv-1.2.2.H9 was engineered into larger human scFv-Fc-1.2.2.H9 and IgG1-1.2.2.H9 formats to improve the binding affinity and to add effector functions within the human immune response. Similar binding kinetics were calculated for scFv-1.2.2.H9 and scFv-Fc-1.2.2.H9 (1.61 nM and 7.685 nM, respectively), whereas, for IgG1-1.2.2.H9, the Michaelis-Menten kinetics revealed an increased affinity of 43.8 pM. None of the purified recombinant 1.2.2.H9 formats were able to neutralize VACV Elstree in vitro. After addition of 1% human complement, the neutralization of ≥50% of VACV Elstree was achieved with 0.0776 µM scFv-Fc-1.2.2.H9 and 0.01324 µM IgG1-1.2.2.H9, respectively. In an in vivo passive immunization NMRI mouse model, 100 µg purified scFv-1.2.2.H9 and the IgG1-1.2.2.H9 partially protected against the challenge with 4 LD50 VACV Munich 1, as 3/6 mice survived. In contrast, in the scFv-Fc-1.2.2.H9 group, only one mouse survived the challenge.

scholarly journals Risk of evolutionary escape from neutralizing antibodies targeting SARS-CoV-2 spike protein

2020 ◽  
Author(s):  
Debra Van Egeren ◽  
Alexander Novokhodko ◽  
Madison Stoddard ◽  
Uyen Tran ◽  
Bruce Zetter ◽  
...  
Keyword(s):  
Neutralizing Antibodies ◽  
Immune Escape ◽  
Passive Immunization ◽  
Spike Protein ◽  
Natural Immunity ◽  
Protein Receptor ◽  
Before And After ◽  
Neutral Genetic Variation ◽  
Escape Mutants

As many prophylactics targeting SARS-CoV-2 are aimed at the spike protein receptor-binding domain (RBD), we examined the risk of immune evasion from previously published RBD-targeting neutralizing antibodies (nAbs). Epitopes for RBD-targeting nAbs overlap one another substantially and can give rise to escape mutants with ACE2 affinities comparable to wild type that still infect cells in vitro. We used evolutionary modeling to predict the frequency of immune escape before and after the widespread presence of nAbs due to vaccines, passive immunization or natural immunity. Our modeling suggests that SARS-CoV-2 mutants with one or two mildly deleterious mutations are expected to exist in high numbers due to neutral genetic variation, and consequently resistance to single or double antibody combinations can develop quickly under positive selection.

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