NASA Studies Immune Response to Flu Vaccine in Space and on Earth
December 29, 2015 - 11:26 AM
Houston, Texas - Every year, as influenza season - and flu shot season--rolls around,
medical experts weigh in on just how effective it will be against that
year's particular strain. What if that equation could take into account a
person's own immune response? Emmanuel Mignot, M.D., Ph.D., known for
discovering that narcolepsy is related to the immune system, is taking
advantage of a unique opportunity to investigate how the immune systems
of twin astronauts Scott and Mark Kelly respond to the seasonal flu
Mignot is conducting his research as an investigator for NASA's Twins Study. NASA's Human Research Program is studying many aspects of Scott Kelly's health during his one-year space flight mission,
with the unique advantage of also studying his identical twin brother,
Mark, on Earth. It will help determine how the immune system changes
during space flight, and how to possibly counterbalance the changes for a
journey to Mars, perhaps through the use of vaccinations.
On the International Space Station,
Scott is exposed to fewer and different pathogens than Mark over the
course of the year. Exposure to bugs, bacteria and viruses on Earth
causes the body to produce more T-cells, which protect us from
infection. These immune cells patrol blood and tissues in the body
looking for invaders, and due to previous exposures, are prepared to
attack. This process strengthens the immune system.
"Each T-cell has a slightly different gene that allows them to react to
specific bacteria or viruses and there are billions of different
receptors in these T-cells to study," said Mignot, also professor of
Psychiatry and Behavioral Sciences at Stanford University, and director
of the Stanford Center for Sleep Sciences and Medicine. "Vaccinations
only protect against one agent, in this case the flu. So we can look at
the specific T-cells that are recruited by the body to fight against the
flu and see how the immune system responds."
Mignot and his team are curious to know whether after a year in an
isolated environment like the space station, if Scott's immune system
will be less responsive or more active due to other stressful exposures
such as isolation and being in an environment far from home and family,
work stress, radiation, microgravity and altered sleep cycles. It is
crucial to understand this, because stress and immune changes could lead
to reactivation of latent infections.
To evaluate his immune system on a molecular level, Scott and Mark
received commercially available flu vaccines at the same time. Flu shots
were administered and blood samples were taken before flight and six
months into the year-long mission. Six months after Scott returns to
Earth, the final flu shots will be administered and blood samples taken.
Samples are taken one week after each flu vaccination because that is
the time when the T-cell immune response is most prominent.
The immune system is very complex. Our bodies are continually fighting
against a variety of bugs. Flu vaccines help because they stimulate the
immune system by pre-activating T-cells in the body causing them to
react faster to block development of disease. Then, when we are exposed
to the flu, the T-cells are already geared up to protect us from
Everyone's immune system is different because of their genes and where
they live and work, and individuals are exposed to different microbes,
bacteria, pathogens and viruses throughout their lifetime. It is
beneficial for researchers such as Mignot to use the latest technology
in gene sequencing, such as the integrative personalized omics profiling
(iPOP), to study the immune system. Omics measures the diversity of
genetic material in our bodies, the totality of all cells such as
molecular interactions, pathways, genes, microbiome, hormones,
antibodies, metabolites, and proteins to name a few.
It will be interesting to compare Scott and Mark's T-cells because it is
not known which T-cells will be recruited to respond to the flu
vaccine. It is hoped, by examining twins who are genetically similar but
are in different environments, that more information can be acquired
about T-cells. This information combined with pre- and post-vaccination
data on 210 twins, ages 8-82 years, from the National Institutes of
Health, may help protect future astronauts on long-duration space
missions, possibly through personalized vaccines. Using Omics,
researchers can see more molecular reactions than ever before and learn
more about immune responses.
"We will be able to determine what portion and pathways of the immune
system are most challenged by space flight," said Mignot. "We'll
calibrate the amount of immune changes present and offer ideas on how to
counterbalance it, for example using higher doses of vaccination for
key viruses to avoid reactivation."
Mignot plans to study as many T-cells as possible and envisions a day
when a flu vaccine will be tailored to a person's genetic and "bug"
makeup by removing the components of the vaccine which cause side
effects and reactions of those who may be genetically predisposed.
NASA's Human Research Program
enables space exploration by reducing the risks to human health and
performance through a focused program of basic, applied and operational
research. This leads to the development and delivery of: human health,
performance, and habitability standards; countermeasures and risk
mitigation solutions; and advanced habitability and medical support
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