scholarly journals Screening of potent neutralizing antibodies against SARS-CoV-2 using convalescent patients-derived phage-display libraries

2021 ◽  
Vol 7 (1) ◽  
Author(s):  
Yongbing Pan ◽  
Jianhui Du ◽  
Jia Liu ◽  
Hai Wu ◽  
Fang Gui ◽  
...  

AbstractAs the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) continues to threaten public health worldwide, the development of effective interventions is urgently needed. Neutralizing antibodies (nAbs) have great potential for the prevention and treatment of SARS-CoV-2 infection. In this study, ten nAbs were isolated from two phage-display immune libraries constructed from the pooled PBMCs of eight COVID-19 convalescent patients. Eight of them, consisting of heavy chains encoded by the immunoglobulin heavy-chain gene-variable region (IGHV)3-66 or IGHV3-53 genes, recognized the same epitope on the receptor-binding domain (RBD), while the remaining two bound to different epitopes. Among the ten antibodies, 2B11 exhibited the highest affinity and neutralization potency against the original wild-type (WT) SARS-CoV-2 virus (KD = 4.76 nM for the S1 protein, IC50 = 6 ng/mL for pseudoviruses, and IC50 = 1 ng/mL for authentic viruses), and potent neutralizing ability against B.1.1.7 pseudoviruses. Furthermore, 1E10, targeting a distinct epitope on RBD, exhibited different neutralization efficiency against WT SARS-CoV-2 and its variants B.1.1.7, B.1.351, and P.1. The crystal structure of the 2B11–RBD complexes revealed that the epitope of 2B11 highly overlaps with the ACE2-binding site. The in vivo experiment of 2B11 using AdV5-hACE2-transduced mice showed encouraging therapeutic and prophylactic efficacy against SARS-CoV-2. Taken together, our results suggest that the highly potent SARS-CoV-2-neutralizing antibody, 2B11, could be used against the WT SARS-CoV-2 and B.1.1.7 variant, or in combination with a different epitope-targeted neutralizing antibody, such as 1E10, against SARS-CoV-2 variants.

Blood ◽  
2006 ◽  
Vol 108 (11) ◽  
pp. 92-92 ◽  
Author(s):  
Don Siegel ◽  
Eric Ostertag

Abstract Thrombotic thrombocytopenic purpura (TTP) is a potentially fatal disorder often associated with autoantibody inhibition of ADAMTS13, a VWF-cleaving protease. Autoantibodies decrease ADAMTS13 activity resulting in accumulation of “unusually” large VWF multimers that mediate platelet thrombosis. To better understand the role autoantibodies play in disease pathogenesis, as well as to develop more specific methods for diagnosis and therapy, it is necessary to characterize pathogenic antibodies on a molecular level, something not possible through analysis of polyclonal patient antisera. The ability to clone large repertoires of patient monoclonal autoantibodies (mAbs) using phage display offers a unique opportunity to address this issue. Three patient (Pt) antibody phage display libraries were created from either splenocytes (Pt1) or peripheral blood lymphocytes (Pt2, Pt3) of individuals with acquired TTP. ADAMTS13-specific mAbs were isolated by panning against recombinant ADAMTS13. Unique clones were identified by DNA sequencing, and their ability to interact with ADAMTS13 was characterized. After antigen selection of Pt1 library, 56 mAbs were randomly-selected from panning rounds 2 through 4 and 68% were found to comprise heavy chains encoded by VH1-69 paired with a VL3 family lambda light chain (3h or 3m). The remaining mAbs comprised heavy chains from the VH1, 3, or 4 families usually paired with kappa light chains. For Pt2 and Pt3 libraries, there was an identical pattern of genetic restriction in immune response to ADAMTS13, i.e. 16 of 24 mAbs (Pt2) and 27 of 27 mAbs (Pt3) were encoded by VH1-69 heavy chains and VL3 family lambda light chains. Though nearly all mAbs were unique, common CDR3 regions among some of the mAbs provided evidence of B-cell clonal expansion and somatic mutation. Though all mAbs bound to ADAMTS13 irrespective of genetic origin, mAbs comprising a VH1-69 heavy chain paired with a VL3 light chain inhibited ADAMTS13 using the FRET-VW73 assay while mAbs comprising a VH1-69 paired with a kappa light chain or comprising non-VH1-69 heavy chains did not inhibit ADAMTS13, with only two exceptions. MAb binding to ADAMTS13 was blocked by preincubation with normal human or murine plasma, but much less so by plasma from TTP patients or ADAMTS13 knockout mice suggesting crossreactivity with mouse ADAMTS13. Certain human mAbs inhibited cleavage of FRET-VWF73 by mouse ADAMTS13 and also inhibited ADAMTS13 in vivo after injection into the internal jugular vein of mice. Rabbit anti-idiotypic antibodies raised against mAb 416, a prototypical VH1-69-encoded mAb, blocked 416’s ability to inhibit human ADAMTS13. Taken together, the cloning and analyses of a large cohort of ADAMTS13 inhibitory autoantibodies derived from 3 unrelated individuals with acquired TTP revealed a genetically restricted immune response. This feature, if common among TTP patients, offers a potential therapeutic target for treatment of TTP, e.g. selective deletion of B-cells utilizing the VH1-69 heavy chain gene. Furthermore, crossreactivity of some human mAbs with murine ADAMTS13 provides a mouse model of acquired ADAMTS13 deficiency that may prove useful for determining the role of autoantibodies in the pathogenesis of TTP, particularly in the context of additional factors (e.g. environmental) that may be required to trigger the disease. Finally, anti-idiotypic mAbs, currently being cloned from rabbit phage display libraries, may help identify pathogenic antibodies in patient plasma and/or lead to novel therapeutic approaches.


2008 ◽  
Vol 82 (12) ◽  
pp. 5912-5921 ◽  
Author(s):  
Zane Kraft ◽  
Katharine Strouss ◽  
William F. Sutton ◽  
Brad Cleveland ◽  
For Yue Tso ◽  
...  

ABSTRACT The vast majority of studies with candidate immunogens based on the human immunodeficiency virus envelope (Env) have been conducted with Env proteins derived from clade B viruses isolated during chronic infection. Whether non-clade B Env protein immunogens will elicit antibodies with epitope specificities that are similar to those of antibodies elicited by clade B Envs and whether the antibodies elicited by Envs derived from early transmitted viruses will be similar to those elicited by Envs derived from viruses isolated during chronic infection are currently unknown. Here we performed immunizations with four clade A Envs, cloned directly from the peripheral blood of infected individuals during acute infection, which differed in lengths and extents of glycosylation. The antibody responses elicited by these four Envs were compared to each other and to those elicited by a well-characterized clade B Env immunogen derived from the SF162 virus, which was isolated during chronic infection. Only one clade A Env, the one with the fewer glycosylation sites, elicited homologous neutralizing antibodies (NAbs); these did not target the V1, V2, or V3 regions. In contrast, all four clade A Envs elicited anti-V3 NAbs against “easy-to-neutralize” clade B and clade A isolates, irrespective of the variable region length and extent of glycosylation of the Env used as an immunogen. These anti-V3 NAbs did not access their epitopes on homologous and heterologous clade A, or B, neutralization-resistant viruses. The length and extent of glycosylation of the variable regions on the clade A Env immunogens tested did not affect the breadth of the elicited NAbs. Our data also indicate that the development of cross-reactive NAbs against clade A viruses faces similar hurdles to the development of cross-reactive anti-clade B NAbs.


2014 ◽  
Vol 116 (5) ◽  
pp. 1322-1333 ◽  
Author(s):  
R.A. Bernedo-Navarro ◽  
M.M. Miyachiro ◽  
M.J. da Silva ◽  
C.F. Reis ◽  
R.A. Conceição ◽  
...  

Antibodies ◽  
2004 ◽  
pp. 105-117 ◽  
Author(s):  
Maxime Moulard ◽  
Mei-Yun Zhang ◽  
Dimiter S. Dimitrov

2017 ◽  
Vol 312 (6) ◽  
pp. F951-F962 ◽  
Author(s):  
Josef G. Heuer ◽  
Shannon M. Harlan ◽  
Derek D. Yang ◽  
Dianna L. Jaqua ◽  
Jeffrey S. Boyles ◽  
...  

Transforming growth factor-alpha (TGFA) has been shown to play a role in experimental chronic kidney disease associated with nephron reduction, while its role in diabetic kidney disease (DKD) is unknown. We show here that intrarenal TGFA mRNA expression, as well as urine and serum TGFA, are increased in human DKD. We used a TGFA neutralizing antibody to determine the role of TGFA in two models of renal disease, the remnant surgical reduction model and the uninephrectomized (uniNx) db/db DKD model. In addition, the contribution of TGFA to DKD progression was examined using an adeno-associated virus approach to increase circulating TGFA in experimental DKD. In vivo blockade of TGFA attenuated kidney disease progression in both nondiabetic 129S6 nephron reduction and Type 2 diabetic uniNx db/db models, whereas overexpression of TGFA in uniNx db/db model accelerated renal disease. Therapeutic activity of the TGFA antibody was enhanced with renin angiotensin system inhibition with further improvement in renal parameters. These findings suggest a pathologic contribution of TGFA in DKD and support the possibility that therapeutic administration of neutralizing antibodies could provide a novel treatment for the disease.


1998 ◽  
Vol 72 (4) ◽  
pp. 3268-3277 ◽  
Author(s):  
I. K. Ramsey ◽  
N. Spibey ◽  
O. Jarrett

ABSTRACT The external surface glycoprotein (SU) of feline leukemia virus (FeLV) contains sites which define the viral subgroup and induce virus-neutralizing antibodies. The subgroup phenotypic determinants have been located to a small variable region, VR1, towards the amino terminus of SU. The sites which function as neutralizing epitopes in vivo are unknown. Recombinant SU proteins were produced by using baculoviruses that contained sequences encoding the SUs of FeLV subgroup A (FeLV-A), FeLV-C, and two chimeric FeLVs (FeLV-215 and FeLV-VC) in which the VR1 domain of FeLV-A had been replaced by the corresponding regions of FeLV-C isolates. The recombinant glycoproteins, designated Bgp70-A, -C, -215, and -VC, respectively, were similar to their wild-type counterparts in several immunoblots and inhibited infection of susceptible cell lines in a subgroup-specific manner. Thus, Bgp70-A interfered with infection by FeLV-A, whereas Bgp70-C, -VC, and -215 did not. Conversely, Bgp70-C, -VC, and -215 blocked infection with FeLV-C, while Bgp70-A had no effect. These results indicate that the site on SU which binds to the FeLV cell surface receptor was preserved in the recombinant glycoproteins. It was also found that the recombinant proteins were able to bind naturally occurring neutralizing antibodies. Bgp70-A, -VC, and -215 interfered with the action of anti-FeLV-A neutralizing antibodies, whereas Bgp70-C did not. Furthermore, Bgp70-C interfered with the action of anti-FeLV-C neutralizing antibodies, while the other proteins did not. These results indicate that the neutralizing epitope(s) of FeLV SU lies outside the subgroup-determining VR1 domain.


1950 ◽  
Vol 91 (1) ◽  
pp. 65-86 ◽  
Author(s):  
Duard L. Walker ◽  
Frank L. Horsfall

There is an exponential linear relationship between the quantity of influenza virus neutralized and the quantity of immune serum employed in in ovo neutralization. The slope of the neutralization line is extremely steep. The concentration of neutralizing antibody can be measured with considerable precision in ovo if the constant virus-varying serum technique is utilized. The amounts of hemagglutination-inhibiting and neutralizing antibodies which are absorbed by a given quantity of influenza virus (PR8) were found to be predictable and the degree of reactivity of these two antibodies was shown to be directly related to the extent of immunization. It was demonstrated that there are marked discrepancies in correlation between antibody titers obtained by in vitro hemagglutination-inhibition and in vivo neutralization techniques and that neutralizing antibody is preferentially absorbed by a given quantity of virus. Inasmuch as the results were found not to be attributable to peculiarities of the techniques employed, it appears that the antibodies measured by hemagglutination-inhibition in vitro and by neutralization in vivo are not identical.


2009 ◽  
Vol 14 (8) ◽  
pp. 991-998 ◽  
Author(s):  
Rui Yu ◽  
Shuang Wang ◽  
Yun-zhou Yu ◽  
Wei-shi Du ◽  
Fang Yang ◽  
...  

The botulinum neurotoxins (BoNTs) produced by Clostridium botulinum are the most poisonous protein substances known. The neutralizing antibodies against botulinum neurotoxin can effectively prevent and cure the toxicosis. Using purified Hc fragments of botulinum neurotoxin serotype A (BoNT/A-Hc) as antigen, 2 specific neutralizing antibodies mapping different epitopes were selected from a fully synthetic human antibody library. The 2 antibodies can effectively inhibit the binding between BoNT/A-Hc and differentiated PC-12 cells in vitro, and the neutralization was evaluated in vivo. Although no single mAb completely protected mice from toxin, they both could prolong time to death when challenged with 20 LD 50s (50% lethal doses) of BoNT/A. When used together, the mAbs completely neutralized 1000 LD50s/mg Ab, suggesting their high neutralizing potency in vivo . The results would lead to further production of neutralizing antibody drugs against BoNT/A. It also proved that it was a quick method to obtain human therapeutic antibodies by selecting from the fully synthetic human antibody phage display library. ( Journal of Biomolecular Screening 2009:991-998)


2010 ◽  
Vol 84 (12) ◽  
pp. 6018-6032 ◽  
Author(s):  
Wendy W. Yeh ◽  
Ishita Rahman ◽  
Peter Hraber ◽  
Rory T. Coffey ◽  
Daiva Nevidomskyte ◽  
...  

ABSTRACT While the simian immunodeficiency virus (SIV)-infected rhesus monkey is an important animal model for human immunodeficiency virus type 1 (HIV-1) infection of humans, much remains to be learned about the evolution of the humoral immune response in this model. In HIV-1 infection, autologous neutralizing antibodies emerge 2 to 3 months after infection. However, the ontogeny of the SIV-specific neutralizing antibody response in mucosally infected animals has not been defined. We characterized the kinetics of the autologous neutralizing antibody response to the transmitted/founder SIVmac251 using a pseudovirion-based TZM-bl cell assay and monitored env sequence evolution using single-genome amplification in four rhesus animals that were infected via intrarectal inoculations. We show that the SIVmac251 founder viruses induced neutralizing antibodies at 5 to 8 months after infection. Despite their slow emergence and low titers, these neutralizing antibodies selected for escape mutants that harbored substitutions and deletions in variable region 1 (V1), V2, and V4 of Env. The neutralizing antibody response was initially focused on V4 at 5 to 8 months after infection and then targeted V1/V2 and V4 by 16 months. These findings reveal a striking delay in the development of neutralizing antibodies in SIVmac-infected animals, thus raising questions concerning the suitability of SIVmac251 as a challenge strain to screen AIDS vaccines that elicit neutralizing antibodies as a means to prevent virus acquisition. They also illustrate the capacity of the SIVmac quasispecies to modify antigenic determinants in response to very modest titers of neutralizing antibodies.


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