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Aging

and

viral

infections

induces

Immunosenescence
One of the success in medical field is the increasing of life expectancy of mankind
...
Immune ageing is
known as ‘’immunosenescence’’
...
This infection contributes a manifestation
of lifelong infection which leads to the exhaustion of component of adaptive immunity such
as T-cell, B-cell and their products
...

Aging study identified a cluture of parameters that predicts mortality at 2, 4 and 6 years
follow up a very old Swedish populations (Ferguson et
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1995; pawlece et
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2009)
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IRP includes CD4:CD8 T-cell ratio, poor Tcell proliferation response to mitogen, high ratio of late to early stage differentiated CD8+ Tcells, increased proportion of T-cells expressing markers associated with senescence, and low
levels of IL-2 and CMV infection
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, 2010)
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it is
cleared that immunosenescence and the IRP are associated with declining of
immunocompetent cells belonging to adaptive immunity results in the aging of individuals
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For instance, the
proliferation and cytotoxicity of NK-cells is observed to decrease with age (Gayoso et al
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While, phagocytic and cytotoxic effect of neutrophils get impaired
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e
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Aging has been also associated with an increased level of
inflammatory mediators in the circulation, a process that has been term coined as inflammaging
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Cytokines
such as IL-6, IL-1ra and CRP has also seen to be useful prognostic marker in very old
peoples (Jylha et al
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At present, telomere length is an important factor in aging
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Leucocytes
telomere is an indicator of morbidity and mortality in humans
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Although for the most
part, adult persons have similar number of peripheral T-cell as the younger but there is a
massive difference in subset and clonal composition of peripheral T-cell, with older persons
posses greater number of cells with a late stage differentiation phenotype i
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KLRG1+/CD28-/CD27-/CD57+ and specificity to epitope of persistent virus like CMV and
EBV
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0, representing of memory CD8+ T- cells
inflation because of clonal expansions of apoptosis resistance CD8+ T- cells
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Old persons
has high number of Th2 cells
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Actually, exercise elevate the production of glucocorticoids in the circulation, which
plays an important role in immune system
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HIV infection can lead to the destruction of T-lymphocytes, results in the declining of
immune system
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It is component of innate immunity, proliferate in response
to infection and give rise to long lived memory cells
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Aging is known to alter the phenotypic characteristic, such as
expressed receptor, and functions of the NK cells
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This

reduction makes the oraganisms more succeptible to viral infections, especially those caused
by HSV, EBV and influenza virus (Biron et al
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The ratio of CD56 bright and CD56
dim decrease, coupled with a downregulation of the inhibitory receptor KLRG1 and an
increase the activity of CD57
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Latent CMV infection lead to the production of high
CD57 and lower amount of KLRG1 and CD158a on NK cells
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Blymphocytes are the major component of adaptive immunity that are produced in the bone
marrow in a series of steps, that are definable by changes of cell surface expression of a
variety of molecules, and is dependent IL-7, where stromal cells provides micro-environment
so that B-cell progenitor can divided into mature B-cells
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Plasma cells produce antibodies that is responsible for neutralizing the antigen
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Pro- B cells expesses very low level of cell surface Igα and Ig β, which induce signal cascade
and results in the heavy chain gene rearrangement and differentiation into pre- B cells and
finally, develop into immature B- cells
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Several mechanisms such as failure to progress in development and increased
apoptosis of both pro and pre B- cells, that limit the B-cells pool in the aged organisms
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Because of reduction in the number of pre- B cells, RAG expression in individual
pro B-cell and pre B-cell are similar in both aged and young organism but total bone marrow
RAG expression get reduced in the aged person
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In CMV infected elderly, the majority of CD28- T cells are
produced in response to infection
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A study revealed that
senescence in T-cells contributes to the deterioration of humoral response in the aged person
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Several recent studies revealed
that overian steroid is responsible for the immune functions in women and therefore,
autoimmune diseases are frequent in women in comparison to male
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It was suggested that overian steroid
associated with menupouse leads to the decreasing of immune functions in post-menupousal

women
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Estrogen receptor are
associated with nuclear membrane
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e
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Estrogen α expression are occurred on immunocompetent cells such as lymphocytes,
dendritic, macrophages etc
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Estrogen promote the activation of B- cells, regulates AID, and production of
immunoglobin G, results in the somatic hypermutation and class switching recombination,
thereby increasing in antibody affinity maturation
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Conclusion is that immune senescence is a major challenge against active aging
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It is overcome by only vaccination strategy in the elderly population to reduce
morbidity and mortality related to infection
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Regular physical exercise
can improve the vaccination response and lower number of exhausted T-cells, increase TCell proliferation and increase the activity of phagocytosis of neutrophils and NK
cytotoxicity and longer telomere length
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Gruver AL1, Hudson LL, Sempowski GD
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J pathol
2007 jan; 211(2): 144-56
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Jorg J Goronzy and Cornelia M Weyand
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Nature immunology 14, 428-436 (2013)
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Richard J
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Lowder, Guillaume Spielmann, Austein B Bigley,
Emily C
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Exercise and the aging immune system
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4
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Mechanism of immunosenescence
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2009, 6:10
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Paolo Sansonia, Rossanna Vescovinia, Frencesco F
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New advances in cmv and immunosenescence
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Volume 55, july 2014, pages 54-62
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Hee Tae Yu and Eui-Cheol Shin
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Epidemiol Health
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7
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Activation-induced and damage-induced cell death in aging
human T- cells
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8
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CMV
and immunosenescence: from basics to clinics
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9
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The impact of menupouse on
immune senescence
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