scholarly journals (In)validating experimentally derived knowledge about influenza A defective interfering particles

2016 ◽  
Vol 13 (124) ◽  
pp. 20160412 ◽  
Author(s):  
Laura E. Liao ◽  
Shingo Iwami ◽  
Catherine A. A. Beauchemin
Keyword(s):  
Mathematical Model ◽  
Experimental Method ◽  
Influenza A Virus ◽  
Influenza A ◽  
Infectious Virus ◽  
Full Length ◽  
Prior Work ◽  
Defective Interfering Particles ◽  
A Cell ◽  
Eclipse Phase

A defective interfering particle (DIP) in the context of influenza A virus is a virion with a significantly shortened RNA segment substituting one of eight full-length parent RNA segments, such that it is preferentially amplified. Hence, a cell co-infected with DIPs will produce mainly DIPs, suppressing infectious virus yields and affecting infection kinetics. Unfortunately, the quantification of DIPs contained in a sample is difficult because they are indistinguishable from standard virus (STV). Using a mathematical model, we investigated the standard experimental method for counting DIPs based on the reduction in STV yield (Bellett & Cooper, 1959, Journal of General Microbiology 21 , 498–509 ( doi:10.1099/00221287-21-3-498 )). We found the method is valid for counting DIPs provided that: (i) an STV-infected cell's co-infection window is approximately half its eclipse phase (it blocks infection by other virions before it begins producing progeny virions), (ii) a cell co-infected by STV and DIP produces less than 1 STV per 1000 DIPs and (iii) a high MOI of STV stock (more than 4 PFU per cell) is added to perform the assay. Prior work makes no mention of these criteria such that the method has been applied incorrectly in several publications discussed herein. We determined influenza A virus meets these criteria, making the method suitable for counting influenza A DIPs.

scholarly journals Mathematical models of Influenza A. virus infections in vitro: Invesigating defective interfering particles and virus release

2021 ◽  
Author(s):  
Laura Liao
Keyword(s):  
Mathematical Models ◽  
Influenza A Virus ◽  
Release Rate ◽  
Influenza A ◽  
Quantitative Methods ◽  
Virus Release ◽  
Virus Infections ◽  
Defective Interfering Particles ◽  
A Cell

In this work, two studies were performed where mathematical models (MM) were used to re-examine and refine quantitative methods based on in vitro assays of influenza A virus infections. In the first study, we investigated the standard experimental method for counting defective interfering particles (DIPs) based on the reduction in standard virus (STV) yield (Bellett & Cooper, 1959). We found the method is valid for counting DIPs provided that: (1) a STV-infected cell’s co-infection window is approximately half its eclipse phase (it blocks infection by other virions before it begins producing progeny virions); (2) a cell co-infected by STV and DIP produces less than 1 STV per 1,000 DIPs; and (3) a high MOI of STV stock (>4 plaque-forming units/cell) is added to perform the assay. Prior work makes no mention of these criteria such that the counting method has been applied incorrectly in several publications discussed herein. We determined influenza A virus meets these criteria, making the method suitable for counting influenza A DIPs. In the second study, we compared a MM with an explicit representation of viral release to a simple MM without explicit release, and investigated whether parameter estimation and the estimation of neuraminidase inhibitor (NAI) efficacy were affected by the use of a simple MM. Since the release rate of influenza A virus is not well-known, a broad range of release rates were considered. If the virus release rate is greater than ∼0.1 h−1, the simple MM provides accurate estimates of infection parameters, but underestimates NAI efficacy, which could lead to underdosing and the emergence of NAI resistance. In contrast, when release is slower than ∼0.1 h−1, the simple MM accurately estimates NAI efficacy, but it can significantly overestimate the infectious lifespan (i.e., the time a cell remains infectious and producing free virus), and it will significantly underestimate the total virus yield and thus the likelihood of resistance emergence. We discuss the properties of, and a possible lower bound for, the influenza A virus release rate. Overall, MMs are a valuable tool in the exploration of the known unknowns (i.e., DIPs, virus release) of influenza A virus infection.

scholarly journals Mathematical models of Influenza A. virus infections in vitro: Invesigating defective interfering particles and virus release

2021 ◽  
Author(s):  
Laura Liao
Keyword(s):  
Mathematical Models ◽  
Influenza A Virus ◽  
Release Rate ◽  
Influenza A ◽  
Quantitative Methods ◽  
Virus Release ◽  
Virus Infections ◽  
Defective Interfering Particles ◽  
A Cell

In this work, two studies were performed where mathematical models (MM) were used to re-examine and refine quantitative methods based on in vitro assays of influenza A virus infections. In the first study, we investigated the standard experimental method for counting defective interfering particles (DIPs) based on the reduction in standard virus (STV) yield (Bellett & Cooper, 1959). We found the method is valid for counting DIPs provided that: (1) a STV-infected cell’s co-infection window is approximately half its eclipse phase (it blocks infection by other virions before it begins producing progeny virions); (2) a cell co-infected by STV and DIP produces less than 1 STV per 1,000 DIPs; and (3) a high MOI of STV stock (>4 plaque-forming units/cell) is added to perform the assay. Prior work makes no mention of these criteria such that the counting method has been applied incorrectly in several publications discussed herein. We determined influenza A virus meets these criteria, making the method suitable for counting influenza A DIPs. In the second study, we compared a MM with an explicit representation of viral release to a simple MM without explicit release, and investigated whether parameter estimation and the estimation of neuraminidase inhibitor (NAI) efficacy were affected by the use of a simple MM. Since the release rate of influenza A virus is not well-known, a broad range of release rates were considered. If the virus release rate is greater than ∼0.1 h−1, the simple MM provides accurate estimates of infection parameters, but underestimates NAI efficacy, which could lead to underdosing and the emergence of NAI resistance. In contrast, when release is slower than ∼0.1 h−1, the simple MM accurately estimates NAI efficacy, but it can significantly overestimate the infectious lifespan (i.e., the time a cell remains infectious and producing free virus), and it will significantly underestimate the total virus yield and thus the likelihood of resistance emergence. We discuss the properties of, and a possible lower bound for, the influenza A virus release rate. Overall, MMs are a valuable tool in the exploration of the known unknowns (i.e., DIPs, virus release) of influenza A virus infection.

scholarly journals Oligomeric States of Full Length Influenza a Virus M2 Proteins on Biological Membranes

2013 ◽  
Vol 104 (2) ◽  
pp. 277a
Author(s):  
Ken-ichi Kawano ◽  
Sayaka Matsuzaki ◽  
Kaoru Oomae ◽  
Yoshiaki Yano ◽  
Katsumi Matsuzaki
Keyword(s):  
Influenza A Virus ◽  
Influenza A ◽  
Biological Membranes ◽  
Full Length

scholarly journals A system for production of defective interfering particles in the absence of infectious influenza A virus

PLoS ONE ◽  
2019 ◽  
Vol 14 (3) ◽  
pp. e0212757 ◽  
Author(s):  
Najat Bdeir ◽  
Prerna Arora ◽  
Sabine Gärtner ◽  
Markus Hoffmann ◽  
Udo Reichl ◽  
...  
Keyword(s):  
Influenza A Virus ◽  
Influenza A ◽  
Defective Interfering Particles

scholarly journals A cell-based screening system for anti-influenza A virus agents

2015 ◽  
Vol 5 (1) ◽  
Author(s):  
Wan Ying Wong ◽  
Sheng Wei Loh ◽  
Wei Lun Ng ◽  
Ming Cheang Tan ◽  
Kok Siong Yeo ◽  
...  
Keyword(s):  
Influenza A Virus ◽  
Influenza A ◽  
Screening System ◽  
A Cell

scholarly journals The Influenza A Virus M2 Cytoplasmic Tail Is Required for Infectious Virus Production and Efficient Genome Packaging

2005 ◽  
Vol 79 (6) ◽  
pp. 3595-3605 ◽  
Author(s):  
Matthew F. McCown ◽  
Andrew Pekosz
Keyword(s):  
Influenza A Virus ◽  
Influenza A ◽  
Infectious Virus ◽  
Virus Production ◽  
Cytoplasmic Tail ◽  
Host Cells ◽  
Wild Type Virus ◽  
Type Virus ◽  
Wild Type ◽  
Virus Particles

ABSTRACT The M2 integral membrane protein encoded by influenza A virus possesses an ion channel activity that is required for efficient virus entry into host cells. The role of the M2 protein cytoplasmic tail in virus replication was examined by generating influenza A viruses encoding M2 proteins with truncated C termini. Deletion of 28 amino acids (M2Stop70) resulted in a virus that produced fourfold-fewer particles but >1,000-fold-fewer infectious particles than wild-type virus. Expression of the full-length M2 protein in trans restored the replication of the M2 truncated virus. Although the M2Stop70 virus particles were similar to wild-type virus in morphology, the M2Stop70 virions contained reduced amounts of viral nucleoprotein and genomic RNA, indicating a defect in vRNP packaging. The data presented indicate the M2 cytoplasmic tail plays a role in infectious virus production by coordinating the efficient packaging of genome segments into influenza virus particles.

scholarly journals Conformational analysis of the full-length M2 protein of the influenza A virus using solid-state NMR

2013 ◽  
Vol 22 (11) ◽  
pp. 1623-1638 ◽  
Author(s):  
Shu Yu Liao ◽  
Keith J. Fritzsching ◽  
Mei Hong
Keyword(s):  
Solid State ◽  
Conformational Analysis ◽  
Influenza A Virus ◽  
Solid State Nmr ◽  
Influenza A ◽  
Full Length ◽  
M2 Protein

scholarly journals Distinct Domains of the Influenza A Virus M2 Protein Cytoplasmic Tail Mediate Binding to the M1 Protein and Facilitate Infectious Virus Production

2006 ◽  
Vol 80 (16) ◽  
pp. 8178-8189 ◽  
Author(s):  
Matthew F. McCown ◽  
Andrew Pekosz
Keyword(s):  
Influenza A Virus ◽  
Influenza A ◽  
Reverse Genetics ◽  
Infectious Virus ◽  
Virus Assembly ◽  
Virus Production ◽  
Cytoplasmic Tail ◽  
M2 Protein ◽  
Virus Particles ◽  
M1 Protein

ABSTRACT The cytoplasmic tail of the influenza A virus M2 protein is highly conserved among influenza A virus isolates. The cytoplasmic tail appears to be dispensable with respect to the ion channel activity associated with the protein but important for virus morphology and the production of infectious virus particles. Using reverse genetics and transcomplementation assays, we demonstrate that the M2 protein cytoplasmic tail is a crucial mediator of infectious virus production. Truncations of the M2 cytoplasmic tail result in a drastic decrease in infectious virus titers, a reduction in the amount of packaged viral RNA, a decrease in budding events, and a reduction in budding efficiency. The M1 protein binds to the M2 cytoplasmic tail, but the M1 binding site is distinct from the sequences that affect infectious virus particle formation. Influenza A virus strains A/Udorn/72 and A/WSN/33 differ in their requirements for M2 cytoplasmic tail sequences, and this requirement maps to the M1 protein. We conclude that the M2 protein is required for the formation of infectious virus particles, implicating the protein as important for influenza A virus assembly in addition to its well-documented role during virus entry and uncoating.

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