ENVB 437 Lecture Notes - Lecture 4: Reassortment, Epitope, Avian Influenza
4 Jun 2018
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Eukaryotic cells and viruses – lecture 04 (January 17th 2017)
Slide 94
- 1918 H1N1 virus:
o flu victims who were frozen in the permafrost were analysed for the virus
o shotgun sequencing
▪ bits of RNA pieced together
o they can make the cDNA from the RNA template
o they can then clone each of the individual segments into a plasmid and expressed to form the viral
particle
- the virus was tested on mice and they all died within 6 days
Slide 96
- 50 times as many virus particles are released from human lung cells a day after infection with the 1918
virus as are released after exposure to a contemporary strain called the Texas virus.
- 13% of body weight is lost by mice 2 days after infection with 1918 flu; weight loss is only transient in
mice infected with the Texas strain.
- 39,000 times more virus particles are found in mouse lung tissue 4 days after infection with 1918 flu than
are found with the Texas virus.
- All mice died within 6 days of infection with 1918 flu; none died from the Texas strain.
- 1918 HA and polymerase genes were essential for optimal virulence (all 8 together the most virulent
human virus ever tested In mice) – why so virulent still unknown but did kill embryonated eggs
Slide 97
- the polymerase genes and nucleoprotein were noticed to also have the same effect
- could it have been due to an increased replication rate?
- It would get much deeper inter ferret lung tissues
- How to study?
o They took piece by piece the 1918 virus and found that the 3 pol genes and nucleoprotein genes
(when inserted into the K173) the only difference was the addition of the 3 pol and 3 nucleoprotein
segment (3P + 3N)
o Made it even more lethal despite the fact that the HA and NA were also causing problems
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find more resources at oneclass.com
slide 97
- The pol were more efficient when the temperature goes up (because birds temperature is about 42°C and
when we get a fever and
- Ferrets are a good model because they are large enough (cat size) and they can pass the virus from one to
another
- *younger people get a bigger cytokine storm
Slide 98
- Antigenic sin:
o The tendency of humans to generate responses to the original strain of the virus and not be able to
react adequately to the target virus
o The new virus has some cross reactivity to the old one
▪ Would that be changed if they used different epitopes?
▪ Is it because they use the same attenuated component?
o The body still has a strong antibody response against H1N1; older people are less effective because
they have a more experienced immune system
Slide 99
- Pigs have both linkages on their receptors, so they can receive both viruses and reassert them in a single
cell and cause novel viruses to be made
Slide 101
- 1st identified in Italt >100 years
- worldwide incidence in domestic poulytry
find more resources at oneclass.com
find more resources at oneclass.com
Document Summary
Eukaryotic cells and viruses lecture 04 (january 17th 2017) 50 times as many virus particles are released from human lung cells a day after infection with the 1918 virus as are released after exposure to a contemporary strain called the texas virus. 13% of body weight is lost by mice 2 days after infection with 1918 flu; weight loss is only transient in mice infected with the texas strain. 39,000 times more virus particles are found in mouse lung tissue 4 days after infection with 1918 flu than are found with the texas virus. All mice died within 6 days of infection with 1918 flu; none died from the texas strain. 1918 ha and polymerase genes were essential for optimal virulence (all 8 together the most virulent human virus ever tested in mice) why so virulent still unknown but did kill embryonated eggs. It would get much deeper inter ferret lung tissues.
