immunological senescence revealed
telomerase76 at hotmail.com
Sun Jun 11 15:30:26 EST 2000
I think that this scenerio is possible. However, perhaps a better way
to re-populate the immune system of older individuals would be to take
some of their stem cells and insert the hTRT gene (encodes for telomerase)
into them. Then, re-insert these stem cells (which should now be able to
divide significantly longer than even compared to a young person's), which
would then re-populate all of the immune cells. Whadya think?
Moses Clarke wrote:
> Moses here: Would it be possible to repopulate the immune system by
> means of stem cells derived from their own cord blood collected sixty
> years before hand? Or perhaps a sample of bone marrow could be taken
> during youth and then stored til old age of the individual and then
> reimplanted to rejuvenate the immune system. Anyway this looks like a
> far better bet than having one's body frozen after death!!!
> Sincerely Moses Clarke
> In article <8htpr7$ph2$1 at sylvester.vcn.bc.ca>,
> Doug Skrecky <oberon at vcn.bc.ca> wrote:
> > Shortage of circulating naive CD8+ T cells provides
> > insights on immunodeficiency in aging.
> > Blood 95: 2860-2868 2000
> > Abstract:
> > Clinical obervations indicate that elderly people are
> > prone to severe, often lethal infectious diseases induced
> > by novel pathogens. Since the ability to mount primary
> > immune responses relies on the availability of naive T
> > cells, the circulating naive T-cell reservoir was evaluated
> > throughout the human life span. Naive T cells were identified
> > as CD95- T lymphocytes for their phenotypic and functional
> > features. Indeed, the lack of CD95 marker is sufficient to
> > identify a population of naive T cells, as defined by
> > coincidence with previously characterized CD45RA+
> > CD62L+ T cells. Naive CD95- T cells, as expected,
> > require a costimulatory signal, such as CD28, to optimally
> > proliferate after anti-CD3 stimulation. Cytofluorimetric
> > analysis of circulating T lymphocytes from 120 healthy
> > subjects ranging in age from 18 to 105 years revealed
> > that naive T cells decreased sharply with age. the
> > younger subjects had a naive T-lymphocyte count of
> > 177 +-28 cells/microL. Surprisingly, the naive T-cell
> > count was lower in CD8+ than in CD4+ subsets at any
> > age, and the oldest individuals were almost completely
> > depleted of circulating naive CD8+ T cells (13 +-4 cells/microL).
> > Concomitantly, a progressive expansion of CD28- T cells
> > occurs with age, which can be interpreted as a compensatory
> > mechanism. These data provide new insights into age
> > related T-cell-mediated immunodeficiency and reveal
> > some analogies of T-cell dynamics between advanced
> > aging and human immunodeficiency virus (HIV) infection.
> > In conclusion, the exhaustion of the naive CD8+ T-cell
> > reservoir, which has never been reported before, suggests
> > that this T-cell pool is a major target of the aging process
> > and may define a parameter possibly related to the life
> > span of humans.
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