Consisting of hundreds of different types of cells and
signalling molecules and controlled by around 8000 genes, your immune system is
one
of the most complicated systems in your body. Since Edward
Jenner first demonstrated the concept of immunisation, scientists have
slowly been increasing our understanding of the immune system and in particular
the effects of ageing or immunosenescence.
In this article, we explore the latest ideas within the field of immunology and
some of the research tools available in our portfolio from leading labs in
immunology research.
The aging immune
system
Your immune system consists of the
adaptive and innate immune system. The innate system is present within the
body from birth and is influenced by your parent’s genetics and their immune
systems. The adaptive immune response develops through your lifetime, as your
body is exposed to viruses and bacteria.
As you age, the immune responses provided by these systems
change. Monocytes start to reduce the amount of interferon produced when
exposed to viral infections. This leads to a
slower and less effective adaptive immune response to infection. In
addition, the increased familiarisation of the immune system to low-grade
chronic inflammation as you age, reduces the immune system’s response to new or
novel pathogens. Vaccinations
are also less efficient. It is therefore easier for a virus to take
advantage of this delayed response, increasing your susceptibility to disease. Discover the story of Charles Janeway, one of the founder’s of innate immunology, and the reagents we have available from his laboratory.
The innate immune system also changes as you age. The thymus
declines in size, decreasing the output of naïve
and antigen-experienced T-cells. The production of
pro-inflammatory cytokines within the thymus increases, leading to an increased
risk of diabetes, osteoporosis and atherosclerosis. Understanding how cytokines
are produced and how they cause inflammation is important in identifying ways
to reverse this aging process. Ximbio’s portfolio contains a variety of
cytokine research tools, including one that
is specifically involved in the acute phase reaction of inflammation.
Your immune system
age – just a number?
However, these immune system changes are not uniform across
individuals. Different people show these immune system changes at different
ages. Recent
research has therefore proposed the possibility of individuals having an
immune age that could differ from their biological ages. Although the decline
of the immune system starts in puberty, it has been proposed that this decline
could be accelerated or slowed by your genetics, lifestyle choices and lifetime
exposure to bacteria and viruses.
Your genetic legacy
It is thought that over 75% of immune traits
are genetically influenced, showing that genetics play a large role in our immune system’s ability
to fight off disease. Some examples include:
-
Some people have managed to avoid HIV infection despite
sharing needles or having unprotected sex with infected partners. Research
in the mid-1990s discovered genetic mutations within these individuals in
the CCR5 gene, that made them completely resistant to HIV. This is because the
chemokine receptors of CCR5 mediate the entry of HIV and SIV into the
susceptible cells. Discover
a monoclonal antibody within our portfolio that specifically targets CCR5.
-
One
in 15 healthy adults carry the pneumonia causing bacterium Streptococcus pneumoniae quite
harmlessly within their respiratory tracts. Investigating how these individuals
are resistant to this bacteria and understanding how this pathogen causes
pneumococcal disease can help provide insights into potential treatments. Explore
some
of the research tools on our portfolio that could be used to study
immunogenic reactions to pneumococcal infections.
Conversely, certain genetic traits can
increase the likelihood of your susceptibility to certain
autoimmune diseases, for example mutations in BRCA genes
can lead to early onset breast or ovarian cancer. This is because BRCA2 is a
tumour suppressor gene and is usually involved in the repair of chromosomal
damage. The Ximbio portfolio contains a
polyclonal antibody that specifically targets BRCA and a monoclonal antibody
that targets PALB2, a partner and localiser of BRCA2.
Your
lifestyle choices have an impact
The lifestyle choices you make can also
have an impact on the age of your immune system. Smokers have a
higher immune age than non-smokers of a similar age and obesity and a sedentary
lifestyle can also have negative effects on your immune age. However, some
lifestyle changes have been shown to have a positive effect on your immune age;
Intermittent
fasting can extend both your lifespan and the number of healthy years (i.e.
Disease free) you experience at the end of your life. Slightly
increasing your vitamin E, vitamin D and zinc intake above the age of 65
can also help enhance immune function. However, in too high a concentration
these nutrients could also suppress the immune system.
A lifetime’s
exposure to bacteria and viruses
Depending on the bacteria or the virus, previous
exposure to an infection can have a huge impact on how your immune system
responds. At birth, your T-cells
typically consist of naïve T-cells that carry the CD45RA glycoprotein. CD45RA
regulates the threshold of T-cell antigen receptor signalling through
dephosphorylation of protein tyrosine kinases. Discover
a range of CD45RA research tools within our portfolio.
As you grow, these T-cell numbers decline
and other T-cells stimulated by infections, vaccinations and your microbiome
(in the gut, your respiratory tract and skin) increase. Research
has shown that people who haven’t been exposed to infections or parasites as a
child, are more likely to suffer from autoimmune diseases in later life.
However, conversely overexposure to infectious diseases and pathogens in
childhood can cause your immune system to age prematurely, though the long-term
effects of this are currently unknown.
Measuring your immune
age
Once the mechanisms behind changes in the age of the immune
system are understood, markers could
be identified to measure individual immune ages. For example frailty and
mortality in older individuals could be measured through the body’s balance
of pro- and anti-inflammatory cytokines. Other methods of measurement could include age
dependant biological changes such as the increased presence of hematopoietic
stem cells, a decrease in natural killer cells and a decline in the production
of new naïve lymphocytes. Research tools targeting each of these biological
changes are critical in ensuring these changes are measured. Some research
tools within the Ximbio portfolio that are relevant to these areas include:
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Monoclonal
antibodies that target CD44. These help track the presences of CD44,
which plays a crucial role in hematopoietic regulation.
-
Monoclonal
antibodies that target Xenopus Natural Killer cells. These antibodies
enable natural killer cells to be separated from T and B cells for easier
identification.
-
Several
monoclonal antibodies that bind to antigens on different lymphocyte cells
for use in lymphocyte research.
Understanding immune age could therefore not just provide a marker of health
and help predict the longevity of the individual, but could also lead to
new strategies to help improve people’s health span in the future; Recent research
has shown that growth hormones could be used to regenerate the thymus gland,
helping to regenerate the immune system in older people or those with
underactive immune systems.