Click to Translate to English Click to Translate to French  Click to Translate to Spanish  Click to Translate to German  Click to Translate to Italian  Click to Translate to Japanese  Click to Translate to Chinese Simplified  Click to Translate to Korean  Click to Translate to Arabic  Click to Translate to Russian  Click to Translate to Portuguese


Forum Home Forum Home > General Discussion > Latest News
  New Posts New Posts RSS Feed - Article Explains Why Egg Base Vaccines Miss on H3N
  FAQ FAQ  Forum Search   Events   Register Register  Login Login

Online Discussion: Tracking new emerging diseases and the next pandemic; Now tracking the Aussie Flu.

Article Explains Why Egg Base Vaccines Miss on H3N

 Post Reply Post Reply
Author
Message
John L. View Drop Down
Admin Group
Admin Group
Avatar

Joined: September 03 2017
Location: New York/USA
Status: Offline
Points: 280
Post Options Post Options   Thanks (0) Thanks(0)   Quote John L. Quote  Post ReplyReply Direct Link To This Post Topic: Article Explains Why Egg Base Vaccines Miss on H3N
    Posted: October 30 2017 at 12:15pm
https://www.sciencedaily.com/releases/2017/10/171030134625.htm

Another reason to only use cellular-based flu vaccine (i.e. flucelvax.)

Science News
from research organizations

How flu shot manufacturing forces influenza to mutate

Egg-based production causes virus to target bird cells, making vaccine less effective

Date:
October 30, 2017
Source:
Scripps Research Institute
Summary:
The common practice of growing influenza vaccine components in chicken eggs disrupts the major antibody target site on the virus surface, rendering the flu vaccine less effective in humans.
Share:
FULL STORY

Click to enlarge
The L194P egg-adaptive mutation dramatically increases the motility of the major epitope on the hemagglutinin of influenza H3 viruses. Red: high motility; white: medium motility; blue: low motility.
Credit: Wilson Lab

According to a new study from scientists at The Scripps Research Institute (TSRI), the common practice of growing influenza vaccine components in chicken eggs disrupts the major antibody target site on the virus surface, rendering the flu vaccine less effective in humans.

"Now we can explain -- at an atomic level -- why egg-based vaccine production is causing problems," said TSRI Research Associate Nicholas Wu, Ph.D., first author of the study, published recently in the journal PLOS Pathogens.

For more than 70 years, manufacturers have made the flu vaccine by injecting influenza into chicken eggs, allowing the virus to replicate inside the eggs and then purifying the fluid from the eggs to get enough of the virus to use in vaccines.

The subtype of influenza in this study, called H3N2, is one of several subtypes shown to mutate when grown in chicken eggs, and the researchers say the new findings further support the case for alternative approaches to growing the virus.

"Any influenza viruses produced in eggs have to adapt to growing in that environment and hence generate mutations to grow better," explained study senior author Ian Wilson, D.Phil., Hansen Professor of Structural Biology at TSRI.

The new study shows exactly why egg-based manufacturing is a problem for the H3N2 subtype. As H3N2 influenza has become more prevalent, scientists formulating the seasonal flu vaccine have sought to include this virus and teach the human immune system to fight it. Despite this effort, recent flu vaccines have proven only 33 percent effective against H3N2 viruses.

Wu used a high-resolution imaging technique called X-ray crystallography to show that -- when grown in eggs -- the H3N2 subtype mutates a key protein to better attach to receptors in bird cells. Specifically, there was a mutation called L194P on the virus's hemagglutinin glycoprotein (HA). This mutation disrupts the region on the protein that is commonly recognized by our immune system.

This means a vaccine containing the mutated version of the protein will not be able to trigger an effective immune response. This leaves the body without protection against circulating strains of H3N2.

In fact, Wu's analysis shows that the current strain of H3N2 used in vaccines already contains this specific mutation L194P on HA. "Vaccine producers need to look at this mutation," cautioned Wu.

The researchers say further studies are needed to investigate replacing the egg-based system. "Other methods are now being used and explored for production of vaccines in mammalian cells using cell-based methods and recombinant HA protein vaccines," said Wilson.

"There's a huge need for flu vaccine research," added Wu.


Story Source:

Materials provided by Scripps Research Institute. Note: Content may be edited for style and length.

John L.
Back to Top
carbon20 View Drop Down
Admin Group
Admin Group


Joined: April 08 2006
Location: West Australia
Status: Offline
Points: 17696
Post Options Post Options   Thanks (0) Thanks(0)   Quote carbon20 Quote  Post ReplyReply Direct Link To This Post Posted: October 30 2017 at 4:23pm
Looks like the very fact we have been producing vaccines, has pushed the mutation of viruses,well that's what they do,

MUTATE....
12 monkeys!!!!!
Back to Top
CRS, DrPH View Drop Down
Expert Level Adviser
Expert Level Adviser


Joined: January 20 2014
Status: Offline
Points: 14890
Post Options Post Options   Thanks (0) Thanks(0)   Quote CRS, DrPH Quote  Post ReplyReply Direct Link To This Post Posted: October 31 2017 at 10:16pm
Good find!  It's about time that they perfected a "universal" flu vaccine, targeting different structural elements of the virus: 

Current flu vaccines have to be changed each year to match strains of virus circulating at the time and they do not always protect people that well, especially older patients with weak immune systems. 

The new vaccine works by using proteins found in the core of the virus rather than those on its surface. Surface proteins stick out like pins from the virus and change all the time, while those in the core are stable.


CRS, DrPH
Back to Top
Hazelpad View Drop Down
Adviser Group
Adviser Group


Joined: September 09 2014
Location: scotland
Status: Offline
Points: 2760
Post Options Post Options   Thanks (0) Thanks(0)   Quote Hazelpad Quote  Post ReplyReply Direct Link To This Post Posted: November 14 2017 at 7:36pm
I still think responses to a Universal FLU Vaccine will be determined by the genetic make up of the person receiving it.

Different HLA haplotypes will display different epitopes ( parts of the virus) with different efficiencies. What may be a dominant epitope for one person may be a weak epitope for others.

For example live attenuated viruses are used in UK nasal vaccine. This allows the immune system access to all the outer and inner proteins of the virus, but you still don't normally get long term memory responses.

From Hazel
(Aah it keeps auto correcting to every name except Hazel. )

Back to Top
 Post Reply Post Reply
  Share Topic   

Forum Jump Forum Permissions View Drop Down