Nature: New research provides new insights into the development of better flu vaccines.

!-- 2, 2020 / / --- Flu season comes every year like a clock, and sooner or later everyone will be infected.
annual flu vaccinations are a key part of public health efforts to control influenza, but the effectiveness of such vaccines is notoriously poor, dropping by 40 to 60 percent in a typical year.
growing evidence that a history of flu virus exposure may undermine the effectiveness of the annual flu vaccine.
Part of the immunity --- whether through natural infection or vaccination--- that has developed during previous flu seasons can interfere with the body's response to new vaccines, so much so that vaccinations are designed to improve the ability to identify previous influenza strains, but are barely able to produce resistance to new strains.
photo source: www.pixabay.com.
now, in a new study, researchers from Washington University's St. Louis School of Medicine have developed a way to assess whether the vaccine activates the immune cells needed to form a lasting immunity against the new strain of the flu virus.
they used the technology to find that flu vaccines can induce antibodies against a wide range of influenza viruses, at least in some people.
findings could help design an improved flu vaccine that not only provides protection against previous flu viruses, but also against new ones.
results were published online August 31, 2020 in the journal Nature, under the title "Human Germinal Centres engage memory and naive B cells after influenza.
, about half of U.S. adults get the flu vaccine each year," said Dr. Ali Ellebedy, a co-author of the paper and an assistant professor of pathology and immunology at the St. Louis School of Medicine at Washington University.
is necessary for public health, but it is also very expensive and inefficient.
we need a once-and-for-all flu vaccine, but we haven't reached that goal yet.
anything that helps us understand how the immune response is produced in cases where we have been exposed to influenza viruses before is important for us to develop a better vaccine.
"the key to long-lasting immunity is the lymph nodes, tiny organs of the immune system that are spread throughout the body."
lymph nodes can easily be ignored by healthy people, but during infection, they become swollen and weak because immune cells interact and multiply.
when a person first comes into contact with the virus--- whether through infection or vaccination, immune cells catch the virus and bring it to the nearest lymph node.
, the virus is presented to so-called naïve B cells, which mature and begin to produce antibodies to fight infection.
once the virus is successfully defeated, most of the immune cells involved in the battle will die, but a few cells will continue to circulate in the blood as long-lived memory B cells.
when a person is exposed to the same virus for the second time, memory B cells are quickly reactivated and start producing antibodies again, bypassing the initial B-cell phase.
The response quickly establishes protection for those who have been reinstated by exactly the same strain of the virus, but for those who have been vaccinated against slightly different strains of the virus, it is not ideal, as is the annual flu vaccine.
If our flu vaccine targets memory cells, then these cells will respond to parts of the new influenza virus strain that have not changed from previous influenza virus strains," said
Ellebedy.
our goal is to keep our immune systems in keeping with new strains of influenza virus, which means we want to focus our immune response on different parts of this year's flu virus.
"In order to gain decades of immunity to new influenza virus strains, influenza virus strains (referred to as vaccine strains) used to prepare influenza vaccines need to be brought to the lymph nodes, where they can be used to train a new set of initial B cells and induce long-lived memory B cells specifically tailored to identify the unique characteristics of the vaccine strain."
to find out what happens in the lymph nodes after flu vaccination, Ellebedy sought the help of Dr. Rachel Presti, an associate professor of medicine at the St. Louis School of Medicine at Washington University, and Dr. Sharlene Teefey, a professor of radiology at the St. Louis School of Medicine at Washington University.
clinical research group on infectious diseases led by Presti coordinated blood and lymph node sampling of healthy volunteers before and after vaccination.
, guided by ultrasound imaging, Teefey carefully extracted so-called birth centers that hold immune cells from the underarm lymph nodes of eight healthy young volunteers who had been vaccinated against the 2018-2019 flu.
the four-price flu vaccine is designed to prevent four different strains of the flu virus.
the volunteers' immune cells after 1 week, 2 weeks, 4 weeks and 9 weeks of vaccination.
Ellebedy and colleagues analyzed immune cells in the birth center to find those activated by vaccination.
of the three volunteers, both memory B cells in the lymph nodes and initial B cells responded to the vaccine strain, suggesting that the vaccine had initiated a process of inducing lasting immunity to the new strain of influenza virus.
, "Our study shows that the flu vaccine can induce two cells in the birth center, but we still don't know how often this happens."
, given that the effectiveness of the flu vaccine hovers around 50 percent, it may not happen as often as we would like.
raises the importance of developing strategies to strengthen birth centers, a step toward a universal flu vaccine.
" (bioon.com) Reference: 1. Jackson S. Turner et al. Human germinal centres engage memory and naive B cells after influenza. Nature, 2020, doi:10.1038/s41586-020-2711-0.2.Study provides insight on how to build a better flu vaccine title . . . . . !-- . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .