First exposure to the pandemic H1N1 virus induced broadly neutralizing antibodies targeting hemagglutinin head epitopes

2021 ◽  
Vol 13 (596) ◽  
pp. eabg4535
Author(s):  
Jenna J. Guthmiller ◽  
Julianna Han ◽  
Lei Li ◽  
Alec W. Freyn ◽  
Sean T. H. Liu ◽  
...  

Broadly neutralizing antibodies are critical for protection against both drifted and shifted influenza viruses. Here, we reveal that first exposure to the 2009 pandemic H1N1 influenza virus recalls memory B cells that are specific to the conserved receptor-binding site (RBS) or lateral patch epitopes of the hemagglutinin (HA) head domain. Monoclonal antibodies (mAbs) generated against these epitopes are broadly neutralizing against H1N1 viruses spanning 40 years of viral evolution and provide potent protection in vivo. Lateral patch-targeting antibodies demonstrated near universal binding to H1 viruses, and RBS-binding antibodies commonly cross-reacted with H3N2 viruses and influenza B viruses. Lateral patch-targeting mAbs were restricted to expressing the variable heavy-chain gene VH3-23 with or without the variable kappa-chain gene VK1-33 and often had a Y-x-R motif within the heavy-chain complementarity determining region 3 to make key contacts with HA. Moreover, lateral patch antibodies that used both VH3-23 and VK1-33 maintained neutralizing capability with recent pH1N1 strains that acquired mutations near the lateral patch. RBS-binding mAbs used a diverse repertoire but targeted the RBS epitope similarly and made extensive contacts with the major antigenic site Sb. Together, our data indicate that RBS- and lateral patch-targeting clones are abundant within the human memory B cell pool, and universal vaccine strategies should aim to drive antibodies against both conserved head and stalk epitopes.

Vaccines ◽  
2020 ◽  
Vol 8 (3) ◽  
pp. 424 ◽  
Author(s):  
Mrityunjoy Biswas ◽  
Tatsuya Yamazaki ◽  
Joe Chiba ◽  
Sachiko Akashi-Takamura

Influenza viruses cause annual epidemics and occasional pandemics. The high diversity of viral envelope proteins permits viruses to escape host immunity. Therefore, the development of a universal vaccine and broadly neutralizing antibodies (bnAbs) is essential for controlling various mutant viruses. Here, we review some potentially valuable bnAbs for influenza; one is a novel passive immunotherapy using a variable domain of heavy chain-only antibody (VHH), and the other is polymeric immunoglobulin A (pIgA) induced by intranasal vaccination. Recently, it was reported that a tetravalent multidomain antibody (MDAb) was developed by genetic fusion of four VHHs, which are bnAbs against the influenza A or B viruses. The transfer of a gene encoding the MDAb–Fc fusion protein provided cross-protection against both influenza A and B viruses in vivo. An intranasal universal influenza vaccine, which can induce neutralizing pIgAs in the upper respiratory tract, is currently undergoing clinical studies. A recent study has revealed that tetrameric IgAs formed in nasal mucosa are more broadly protective against influenza than the monomeric and dimeric forms. These broadly neutralizing antibodies have high potential to control the currently circulating influenza virus.


2017 ◽  
Vol 91 (24) ◽  
Author(s):  
Troy C. Sutton ◽  
Elaine W. Lamirande ◽  
Kevin W. Bock ◽  
Ian N. Moore ◽  
Wouter Koudstaal ◽  
...  

ABSTRACT Influenza viruses of the H1N1, H2N2, and H3N2 subtypes have caused previous pandemics. H2 influenza viruses represent a pandemic threat due to continued circulation in wild birds and limited immunity in the human population. In the event of a pandemic, antiviral agents are the mainstay for treatment, but broadly neutralizing antibodies (bNAbs) may be a viable alternative for short-term prophylaxis or treatment. The hemagglutinin stem binding bNAbs CR6261 and CR9114 have been shown to protect mice from severe disease following challenge with H1N1 and H5N1 and with H1N1, H3N2, and influenza B viruses, respectively. Early studies with CR6261 and CR9114 showed weak in vitro activity against human H2 influenza viruses, but the in vivo efficacy against H2 viruses is unknown. Therefore, we evaluated these antibodies against human- and animal-origin H2 viruses A/Ann Arbor/6/1960 (H2N2) (AA60) and A/swine/MO/4296424/06 (H2N3) (Sw06). In vitro, CR6261 neutralized both H2 viruses, while CR9114 only neutralized Sw06. To evaluate prophylactic efficacy, mice were given CR6261 or CR9114 and intranasally challenged 24 h later with lethal doses of AA60 or Sw06. Both antibodies reduced mortality, weight loss, airway inflammation, and pulmonary viral load. Using engineered bNAb variants, antibody-mediated cell cytotoxicity reporter assays, and Fcγ receptor-deficient (Fcer1g −/−) mice, we show that the in vivo efficacy of CR9114 against AA60 is mediated by Fcγ receptor-dependent mechanisms. Collectively, these findings demonstrate the in vivo efficacy of CR6261 and CR9114 against H2 viruses and emphasize the need for in vivo evaluation of bNAbs. IMPORTANCE bNAbs represent a strategy to prevent or treat infection by a wide range of influenza viruses. The evaluation of these antibodies against H2 viruses is important because H2 viruses caused a pandemic in 1957 and could cross into humans again. We demonstrate that CR6261 and CR9114 are effective against infection with H2 viruses of both human and animal origin in mice, despite the finding that CR9114 did not display in vitro neutralizing activity against the human H2 virus. These findings emphasize the importance of in vivo evaluation and testing of bNAbs.


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.


2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Adrian Creanga ◽  
Rebecca A. Gillespie ◽  
Brian E. Fisher ◽  
Sarah F. Andrews ◽  
Julia Lederhofer ◽  
...  

AbstractBroadly neutralizing antibodies (bnAbs) have been developed as potential countermeasures for seasonal and pandemic influenza. Deep characterization of these bnAbs and polyclonal sera provides pivotal understanding for influenza immunity and informs effective vaccine design. However, conventional virus neutralization assays require high-containment laboratories and are difficult to standardize and roboticize. Here, we build a panel of engineered influenza viruses carrying a reporter gene to replace an essential viral gene, and develop an assay using the panel for in-depth profiling of neutralizing antibodies. Replication of these viruses is restricted to cells expressing the missing viral gene, allowing it to be manipulated in a biosafety level 2 environment. We generate the neutralization profile of 24 bnAbs using a 55-virus panel encompassing the near-complete diversity of human H1N1 and H3N2, as well as pandemic subtype viruses. Our system offers in-depth profiling of influenza immunity, including the antibodies against the hemagglutinin stem, a major target of universal influenza vaccines.


Viruses ◽  
2021 ◽  
Vol 13 (6) ◽  
pp. 977
Author(s):  
Kobporn Boonnak ◽  
Chayasin Mansanguan ◽  
Dennis Schuerch ◽  
Usa Boonyuen ◽  
Hatairat Lerdsamran ◽  
...  

Influenza viruses continue to be a major public health threat due to the possible emergence of more virulent influenza virus strains resulting from dynamic changes in virus adaptability, consequent of functional mutations and antigenic drift in surface proteins, especially hemagglutinin (HA) and neuraminidase (NA). In this study, we describe the genetic and evolutionary characteristics of H1N1, H3N2, and influenza B strains detected in severe cases of seasonal influenza in Thailand from 2018 to 2019. We genetically characterized seven A/H1N1 isolates, seven A/H3N2 isolates, and six influenza B isolates. Five of the seven A/H1N1 viruses were found to belong to clade 6B.1 and were antigenically similar to A/Switzerland/3330/2017 (H1N1), whereas two isolates belonged to clade 6B.1A1 and clustered with A/Brisbane/02/2018 (H1N1). Interestingly, we observed additional mutations at antigenic sites (S91R, S181T, T202I) as well as a unique mutation at a receptor binding site (S200P). Three-dimensional (3D) protein structure analysis of hemagglutinin protein reveals that this unique mutation may lead to the altered binding of the HA protein to a sialic acid receptor. A/H3N2 isolates were found to belong to clade 3C.2a2 and 3C.2a1b, clustering with A/Switzerland/8060/2017 (H3N2) and A/South Australia/34/2019 (H3N2), respectively. Amino acid sequence analysis revealed 10 mutations at antigenic sites including T144A/I, T151K, Q213R, S214P, T176K, D69N, Q277R, N137K, N187K, and E78K/G. All influenza B isolates in this study belong to the Victoria lineage. Five out of six isolates belong to clade 1A3-DEL, which relate closely to B/Washington/02/2009, with one isolate lacking the three amino acid deletion on the HA segment at position K162, N163, and D164. In comparison to the B/Colorado/06/2017, which is the representative of influenza B Victoria lineage vaccine strain, these substitutions include G129D, G133R, K136E, and V180R for HA protein. Importantly, the susceptibility to oseltamivir of influenza B isolates, but not A/H1N1 and A/H3N2 isolates, were reduced as assessed by the phenotypic assay. This study demonstrates the importance of monitoring genetic variation in influenza viruses regarding how acquired mutations could be associated with an improved adaptability for efficient transmission.


Science ◽  
2016 ◽  
Vol 352 (6288) ◽  
pp. 1001-1004 ◽  
Author(s):  
C.-L. Lu ◽  
D. K. Murakowski ◽  
S. Bournazos ◽  
T. Schoofs ◽  
D. Sarkar ◽  
...  

1995 ◽  
Vol 108 (4) ◽  
pp. 1779-1789 ◽  
Author(s):  
K.C. Chang ◽  
K. Fernandes ◽  
M.J. Dauncey

Members of the myosin heavy chain (MyHC) gene family show developmental stage- and spatial-specificity of expression. We report on the characterization and identification of a porcine skeletal fast MyHC gene, including its corresponding 5′ end cDNA and 5′ regulatory region. This MyHC isoform was found exclusively in skeletal muscles from about the last quarter of gestation through to adulthood. Expression of this isoform was higher postnatally and its spatial distribution resembled a rosette cluster; each with a ring of fast fibres surrounding a central slow fibre. This rosette pattern was absent in the adult diaphragm but about 20% of the fibres continued to express this MyHC isoform. Further in vivo expression studies, in a variety of morphologically and functionally diverse muscles, showed that this particular skeletal MyHC isoform was expressed in fast oxidative-glycolytic fibres, suggesting that it was the equivalent of the fast IIA isoform. Two domains in the upstream regulatory region were found to confer differentiation-specific expression on C2 myotubes (−1007 to -828 and -455 to -101), based on in vitro transient expression assays using the chloramphenicol acetyltransferase (CAT) reporter gene. Interestingly, for high levels of CAT expression to occur, a 3′ region, extending from the transcriptional start site to part. of intron 2, must be present in all the DNA constructs used.


2001 ◽  
Vol 280 (5) ◽  
pp. C1262-C1276 ◽  
Author(s):  
Carola E. Wright ◽  
P. W. Bodell ◽  
F. Haddad ◽  
A. X. Qin ◽  
K. M. Baldwin

The main goal of this study was to examine the transcriptional activity of different-length β-myosin heavy chain (β-MHC) promoters in the hypertensive rodent heart using the direct gene transfer approach. A hypertensive state was induced by abdominal aortic constriction (AbCon) sufficient to elevate mean arterial pressure by ∼45% relative to control. Results show that β-MHC promoter activity of all tested wild-type constructs, i.e., −3500, −408, −299, −215, −171, and −71 bp, was significantly increased in AbCon hearts. In the normal control hearts, expression of the −71-bp construct was comparable to that of the promoterless vector, but its induction by AbCon was comparable to that of the other constructs. Additional results, based on mutation analysis and DNA gel mobility shift assays targeting βe1, βe2, GATA, and βe3 elements, show that these previously defined cis-elements in the proximal promoter are indeed involved in maintaining basal promoter activity; however, none of these elements, either individually or collectively, appear to be major players in mediating the hypertension response of the β-MHC gene. Collectively, these results indicate that three separate regions on the β-MHC promoter are involved in the induction of the gene in response to hypertension: 1) a distal region between −408 and −3500 bp, 2) a proximal region between −299 and −215 bp, and 3) a basal region within −71 bp of the transcription start site. Future research needs to further characterize these responsive regions to more fully delineate β-MHC transcriptional regulation in response to pressure overload.


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