Growth Kinetics of Influenza C Virus Antigenic Mutants that Escaped from Anti-Hemagglutinin Esterase Monoclonal Antibodies and Viral Antigenic Changes Found in Field Isolates

The antigenicity of the hemagglutinin esterase (HE) glycoprotein of influenza C virus is known to be stable; however, information about residues related to antigenic changes has not yet been fully acquired. Using selection with anti-HE monoclonal antibodies, we previously obtained some escape mutants and identified four antigenic sites, namely, A-1, A-2, A-3, and Y-1. To confirm whether the residues identified as the neutralizing epitope possibly relate to the antigenic drift, we analyzed the growth kinetics of these mutants. The results showed that some viruses with mutations in antigenic site A-1 were able to replicate to titers comparable to that of the wild-type, while others showed reduced titers. The mutants possessing substitutions in the A-2 or A-3 site replicated as efficiently as the wild-type virus. Although the mutant containing a deletion at positions 192 to 195 in the Y-1 site showed lower titers than the wild-type virus, it was confirmed that this region in the 190-loop on the top side of the HE protein is not essential for viral propagation. Then, we revealed that antigenic changes due to substitutions in the A-1, A-3, and/or Y-1 site had occurred in nature in Japan for the past 30 years. These results suggest that some residues (i.e., 125, 176, 192) in the A-1 site, residue 198 in the A-3 site, and residue 190 in the Y-1 site are likely to mediate antigenic drift while maintaining replicative ability.

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Kinetics of Neutralizing Antibodies of COVID-19 Patients Tested Using Clinical D614G, B.1.1.7 and B 1.351 Isolates in Microneutralization Assays

Viruses ◽

10.3390/v13060996 ◽

2021 ◽

Vol 13 (6) ◽

pp. 996

Author(s):

Jenni Virtanen ◽

Ruut Uusitalo ◽

Essi M. Korhonen ◽

Kirsi Aaltonen ◽

Teemu Smura ◽

...

Keyword(s):

Neutralizing Antibodies ◽

Acute Infection ◽

Clinical Isolates ◽

Wild Type Virus ◽

Type Virus ◽

Wild Type ◽

Kinetics Of

Increasing evidence suggests that some newly emerged SARS-CoV-2 variants of concern (VoCs) resist neutralization by antibodies elicited by the early-pandemic wild-type virus. We applied neutralization tests to paired recoveree sera (n = 38) using clinical isolates representing the first wave (D614G), VoC1, and VoC2 lineages (B.1.1.7 and B 1.351). Neutralizing antibodies inhibited contemporary and VoC1 lineages, whereas inhibition of VoC2 was reduced 8-fold, with 50% of sera failing to show neutralization. These results provide evidence for the increased potential of VoC2 to reinfect previously SARS-CoV-infected individuals. The kinetics of NAbs in different patients showed similar decline against all variants, with generally low initial anti-B.1.351 responses becoming undetectable, but with anti-B.1.1.7 NAbs remaining detectable (>20) for months after acute infection.

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Noncapped Genomic RNA Are Critical for Alphaviral Infection and Pathogenicity

Proceedings ◽

10.3390/proceedings2020050044 ◽

2020 ◽

Vol 50 (1) ◽

pp. 44

Author(s):

Autumn T. LaPointe ◽

Kevin J Sokoloski

Keyword(s):

Growth Kinetics ◽

Particle Production ◽

Immune Cell ◽

Wild Type Virus ◽

Type Virus ◽

Wild Type ◽

Genomic Rnas ◽

Viral Rnas ◽

The Impact

Alphaviruses are positive-sense RNA arthropod-borne viruses that represent a significant threat to public health. During alphaviral replication, significant quantities of viral genomic RNAs that lack a canonical 5’ cap structure are produced and packaged into viral particles, despite the fact that the noncapped genomes cannot be translated and are essentially noninfectious. Previously, we have reported that the capping efficiency of nsP1, the alphaviral capping enzyme, of Sindbis virus (SINV) could be modulated via point mutation. It was found that increasing RNA capping efficiency led to decreased viral growth kinetics via decreased particle production, despite increased innate immune evasion, whereas decreasing capping efficiency led to wild-type growth kinetics and particle production. This led to the conclusion that the noncapped viral RNAs meaningfully contribute to the biology of alphaviral infections at the molecular level. To determine the importance of the noncapped viral RNAs in vivo, we characterized the impact of altered capping efficiency in a murine model of infection utilizing a neurovirulent strain of SINV. Mice infected with the nsP1 mutant with decreased capping exhibited wild-type rates of mortality, weight loss, and neurological symptoms. Conversely, the mice infected with the increased capping nsP1 mutant showed significantly reduced mortality and morbidity compared to mice infected with the wild-type virus. Interestingly, viral titers in the ankle, serum, and brain were equivalent between the wild-type virus and the two mutant viruses. Importantly, examination of the brain tissue revealed that mice infected with the increased capping mutant had significantly reduced immune cell infiltration and expression of proinflammatory cytokines compared to the decreased capping mutant and wild-type virus. Collectively, these data indicate that the noncapped viral RNAs have important roles during the early and late stages of alphaviral infection and suggest a novel mechanism by which noncapped viral RNA aids in viral pathogenesis.

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Antibody Escape Kinetics of Equine Infectious Anemia Virus Infection of Horses

Journal of Virology ◽

10.1128/jvi.00137-15 ◽

2015 ◽

Vol 89 (13) ◽

pp. 6945-6951 ◽

Cited By ~ 4

Author(s):

Elissa J. Schwartz ◽

Seema Nanda ◽

Robert H. Mealey

Keyword(s):

Neutralizing Antibodies ◽

Equine Infectious Anemia Virus ◽

Wild Type Virus ◽

Type Virus ◽

Wild Type ◽

Fitness Costs ◽

Equine Infectious Anemia ◽

Anemia Virus ◽

Kinetics Of ◽

Virus Fitness

Lentivirus escape from neutralizing antibodies (NAbs) is not well understood. In this work, we quantified antibody escape of a lentivirus, using antibody escape data from horses infected with equine infectious anemia virus. We calculated antibody blocking rates of wild-type virus, fitness costs of mutant virus, and growth rates of both viruses. These quantitative kinetic estimates of antibody escape are important for understanding lentiviral control by antibody neutralization and in developing NAb-eliciting vaccine strategies.

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Attenuation of Foot-and-Mouth Disease Virus by Engineered Viral Polymerase Fidelity

Journal of Virology ◽

10.1128/jvi.00081-17 ◽

2017 ◽

Vol 91 (15) ◽

Cited By ~ 27

Author(s):

Devendra K. Rai ◽

Fayna Diaz-San Segundo ◽

Grace Campagnola ◽

Anna Keith ◽

Elizabeth A. Schafer ◽

...

Keyword(s):

Growth Kinetics ◽

Foot And Mouth Disease ◽

Mouth Disease ◽

Wild Type Virus ◽

Type Virus ◽

Wild Type ◽

Vaccine Candidates ◽

Polymerase Fidelity ◽

Mouth Disease Virus ◽

Foot And Mouth

ABSTRACT Foot-and-mouth disease virus (FMDV) RNA-dependent RNA polymerase (RdRp) (3Dpol) catalyzes viral RNA synthesis. Its characteristic low fidelity and absence of proofreading activity allow FMDV to rapidly mutate and adapt to dynamic environments. In this study, we used the structure of FMDV 3Dpol in combination with previously reported results from similar picornaviral polymerases to design point mutations that would alter replication fidelity. In particular, we targeted Trp237 within conserved polymerase motif A because of the low reversion potential inherent in the single UGG codon. Using biochemical and genetic tools, we show that the replacement of tryptophan 237 with phenylalanine imparts higher fidelity, but replacements with isoleucine and leucine resulted in lower-fidelity phenotypes. Viruses containing these W237 substitutions show in vitro growth kinetics and plaque morphologies similar to those of the wild-type (WT) A24 Cruzeiro strain in BHK cells, and both high- and low-fidelity variants retained fitness during coinfection with the wild-type virus. The higher-fidelity W237F (W237FHF) mutant virus was more resistant to the mutagenic nucleoside analogs ribavirin and 5-fluorouracil than the WT virus, whereas the lower-fidelity W237I (W237ILF) and W237LLF mutant viruses exhibited lower ribavirin resistance. Interestingly, the variant viruses showed heterogeneous and slightly delayed growth kinetics in primary porcine kidney cells, and they were significantly attenuated in mouse infection experiments. These data demonstrate, for a single virus, that either increased or decreased RdRp fidelity attenuates virus growth in animals, which is a desirable feature for the development of safer and genetically more stable vaccine candidates. IMPORTANCE Foot-and-mouth disease (FMD) is the most devastating disease affecting livestock worldwide. Here, using structural and biochemical analyses, we have identified FMDV 3Dpol mutations that affect polymerase fidelity. Recombinant FMDVs containing substitutions at 3Dpol tryptophan residue 237 were genetically stable and displayed plaque phenotypes and growth kinetics similar to those of the wild-type virus in cell culture. We further demonstrate that viruses harboring either a W237FHF substitution or W237ILF and W237LLF mutations were highly attenuated in animals. Our study shows that obtaining 3Dpol fidelity variants by protein engineering based on polymerase structure and function could be exploited for the development of attenuated FMDV vaccine candidates that are safer and more stable than strains obtained by selective pressure via mutagenic nucleotides or adaptation approaches.

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Persistent infection with an influenza C virus variant is dominantly established in the presence of the parental wild-type virus

Virus Research ◽

10.1016/s0168-1702(98)00014-8 ◽

1998 ◽

Vol 54 (1) ◽

pp. 51-58 ◽

Cited By ~ 1

Author(s):

Manfred Marschall ◽

Anke Helten ◽

Anne Hechtfischer ◽

Anke Zach ◽

Herbert Meier-Ewert

Keyword(s):

Persistent Infection ◽

Wild Type Virus ◽

Type Virus ◽

Wild Type ◽

Virus Variant ◽

Influenza C Virus

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The mechanism of antigenic drift in influenza virus: sequence changes in the haemagglutinin of variants selected with monoclonal hybridoma antibodies

Philosophical Transactions of the Royal Society of London Series B Biological Sciences ◽

10.1098/rstb.1980.0007 ◽

1980 ◽

Vol 288 (1029) ◽

pp. 313-326 ◽

Cited By ~ 13

Keyword(s):

Monoclonal Antibody ◽

Influenza Virus ◽

Monoclonal Antibodies ◽

Hong Kong ◽

Amino Acid ◽

The Other ◽

Wild Type Virus ◽

Type Virus ◽

Wild Type ◽

Sequence Change

Antigenic variants of the A/PR8 (H0N1) and A/Hong Kong/68 (H3N2) strains of influenza virus were isolated after a single passage of these viruses in the presence of monoclonal hybridoma antibodies to the haemagglutinin. Hyperimmune rabbit antisera reacted (in haemagglutination-inhibition tests) to high titre with both wild-type and variant viruses, but the monoclonal antibodies, which reacted with the wild-type virus to titres of the order of 1/10 5 did not react at all (or to very low titre) with the variants that they selected. This suggests that the changes occurring in the monoclonal variants are restricted to a single antigenic site out of many on the haemagglutinin molecule. Amino acid analysis of the soluble tryptic peptides from the haemagglutinin ‘spikes’ of wild-type and variant viruses suggest that the dramatic loss in the ability of the variants to bind the monoclonal antibody used in their selection is associated with a single change in the amino acid sequence of the large haemagglutinin polypeptide, HA 1 . For PR8 virus, eight out of ten variants selected with one monoclonal antibody showed the same sequence change of serine to leucine in the HA 1 polypeptide. The change in the other two variants was not determined. No sequence data on PR8 haemagglutinin are available, so the experiments were continued with a Hong Kong (H3N2) strain where much of the sequence of HA 1 and HA 2 is known. Three different monoclonal hybridoma antibodies to A/Mem/1/71 (H3N2) haemagglutinin were used to select a total of ten variants of this virus. Variants selected with one monoclonal antibody were not recognized by the other two monoclonal antibodies as being different from wild-type virus, suggesting that the three antibodies bound to different sites on the surface of the haemagglutinin molecules. Each of the variants occurred with a frequency of about 1 in 105 in the wild-type virus. One group of our variants selected with H14/A2 monoclonal antibody showed the same antigenic properties and the same sequence change (asparagine to lysine) in the N-terminal half of HA 1 . Of three variants selected with H14/A20, two showed a different change at a locus also in the N-terminal region of HA 1 (a proline was replaced by serine in one variant and by leucine in the other). Of the other three variants (selected with H14/A21 monoclonal antibody) one showed a change in HAX of serine to tyrosine. This change occurred in residue number 37 of cyanogen bromide fragment 2 (CN2). In the other two variants the change in HAX has not been determined, but in these a tryptic peptide comprising residues 49-56 of CN2 was missing. The tryptic peptides of the HA 1 polypeptide, showing changes in the variants selected with monoclonal antibodies, were also found to undergo sequence changes in naturally occurring Hong Kong variants isolated from man. In each case, however, the sequence changes in the monoclonal variants were different from those in the field strains. No changes were found in the HA 2 polypeptide from any of the variants.

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Blocking Immune Evasion as a Novel Approach for Prevention and Treatment of Herpes Simplex Virus Infection

Journal of Virology ◽

10.1128/jvi.77.23.12639-12645.2003 ◽

2003 ◽

Vol 77 (23) ◽

pp. 12639-12645 ◽

Cited By ~ 26

Author(s):

Kara A. Judson ◽

John M. Lubinski ◽

Ming Jiang ◽

Yueh Chang ◽

Roselyn J. Eisenberg ◽

...

Keyword(s):

Monoclonal Antibodies ◽

Herpes Simplex Virus ◽

Herpes Simplex ◽

Immune Evasion ◽

Mutant Virus ◽

Wild Type Virus ◽

Type Virus ◽

Wild Type ◽

Herpes Simplex Virus Glycoprotein ◽

Simplex Virus

ABSTRACT Many microorganisms encode immune evasion molecules to escape host defenses. Herpes simplex virus type 1 glycoprotein gC is an immunoevasin that inhibits complement activation by binding complement C3b. gC is expressed on the virus envelope and infected cell surface, which makes gC potentially accessible to blocking antibodies. Mice passively immunized with gC monoclonal antibodies prior to infection were protected against herpes simplex virus challenge only if the gC antibodies blocked C3b binding. Mice treated 1 or 2 days postinfection with gC monoclonal antibodies that block C3b binding had less severe disease than control mice treated with nonimmune immunoglobulin G (IgG). Mice immunized with gC protein produced antibodies that blocked C3b binding to gC. Immunized mice were significantly protected against challenge by wild-type virus, but not against a gC mutant virus lacking the C3b binding domain, suggesting that protection was mediated by antibodies that target the gC immune evasion domain. IgG and complement from subjects immunized with an experimental herpes simplex virus glycoprotein gD vaccine neutralized far more mutant virus defective in immune evasion than wild-type virus, supporting the importance of immune evasion molecules in reducing vaccine potency. These results suggest that it is possible to block immune evasion domains on herpes simplex virus and that this approach has therapeutic potential and may enhance vaccine efficacy.

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