Science: Revealing why seasonal flu vaccinations can only stay in effect for a year.

August 20, 2020 /--- In a new study, researchers from research institutions such as Emory University in the United States offer new insights into why the increase in immunity after seasonal flu vaccination lasts only a few months, not years.
results were published online August 13, 2020 in the journal Science, under the title "Influenza vaccine-induced human bone marrow plasma cells decline within a year after the prison."
author of the paper is Dr. Rafai Ahmed, Director of the Emory Vaccine Center at Emory University.
images from Science, 2020, doi:10.1126/science.aaz8432.
immune cells that produce antibodies (antibody-producing cells, also known as antibody secretion cells, or plasma cells later) are home to bone marrow.
the seasonal flu vaccine does increase the number of influenza-specific antibodies producing cells in the bone marrow.
, however, the authors found that most of the newly produced cells would disappear within a year.
the findings could serve as a reference for the design of a more durable "universal" influenza vaccine and ongoing vaccine studies against SARS-CoV-2.
We need to get an annual flu shot, partly because influenza viruses infected with humans mutate and exchange genes with influenza viruses that infect birds and pigs, but also because the antibody production cells highlighted in this study decline over time.
most vaccine studies take blood samples from participants, and within weeks of vaccination, antibody-producing cells can be found in the blood.
Ahmed and his team took additional steps to obtain bone marrow samples--- a more invasive procedure.
people already have flu-specific plasma cells, the types of immune cells that secrete large amounts of antibodies.
, the authors need to distinguish between antibodies produced by pre-existing cells and those stimulated by strains present in seasonal influenza vaccines.
, lead author of the paper and a postdoctoral researcher at Ahmed Labs, said, "We were able to track specific cells produced by seasonal flu vaccines because they produced unique antibodies that can be identified using sequencing techniques."
we can observe that these new antibodies increase in the bone marrow one month after vaccination and then decrease after one year.
, on the other hand, flu antibodies in the bone marrow remained at a stable level for a year until the vaccine was given.
," Ahmed said, "it shows that it's not enough to just get into the bone marrow."
cells must find a micro-environment (or niche) in the bone marrow, where they stand on the heel and make genetic expression and metabolic changes to promote longevity.
" bone marrow collection was conducted between 2009 and 2018 in collaboration with Professor Edmund K. Waller of Emory University School of Medicine.
the study, 53 healthy volunteers agreed to provide bone marrow before seasonal flu vaccination, one month after vaccination, and follow-up about a year later.
month after vaccination, the proportion of influenza-specific cell populations increased (from an average of 0.8 per cent to 1.9 per cent).
follow-up a few months later found that the number had dropped to baseline levels.
looking for new vaccine-specific antibody secretion cells requires analyzing the DNA of these cells and exploring the antibodies they make, and then tracking their abundance in the blood and bone marrow.
for most newly produced plasma cell lineles, 70 to 99 percent of them disappear after a year.
good news is that, especially for those involved in vaccine studies, levels of antibody secretion cells in the blood are associated with long-term reactions in the bone marrow.
, vaccine researchers can continue to monitor the immune response by looking for antibody secretion cells in the blood.
addition, Ahmed said, a vaccine additive called adjuvant is expected to increase the long-term presence of antibody secretion cells in the bone marrow.
standard inactivated influenza vaccine does not contain adage.
also promotes the formation of the birth center, where plasma cells that secrete high affinity antibodies are produced.
may be important for promoting the formation of long-lived plasma cells.
(bioon.com) Reference: 1. Carl W. Davis et al. Influenza vaccine-induced human bone marrow plasma cells decline within a year after inging. Science, 2020, doi:10.1126/science.aaz8432.2.Flu Ings don't 'stick' long-term in bone marrow.