July 06, 2008
Immune System Rejuvenation Needed For TB Treatment

Aged immune systems hobble the ability of old people to fight off tuberculosis (TB). These aged immune systems also explain higher rates of death of old people from the flu and other infectious diseases.

COLUMBUS, Ohio – Manipulating the immune system in elderly people appears to be the most likely way to help older patients wage an effective battle against tuberculosis, a new study suggests.

Mathematical modeling of how mice respond to TB infection suggests that potential therapy options for elderly TB patients could either increase their white blood cell count or enhance infected cells’ interaction with their immune system.

This report illustrates how scientists trying to treat specific diseases end up running into the need to rejuvenate parts of the body. In this case what is needed is immune system rejuvenation.

Simulations of TB infection in an old mouse showed that increasing the number of infection-fighting white blood cells, called CD4 T cells, could be particularly effective at bolstering the mouse’s immune response, which naturally slows with aging. Older humans have similar delays in their immune response, meaning that they have a much more difficult time controlling TB than do younger people with an active infection.

The math modeling also suggested that making changes to macrophages, cells that essentially eat infecting bacteria, could enhance those cells’ interactions with other warriors in the immune system, reducing the concentration of bacteria in the lungs associated with TB infection.

As we age senescent immune cells end up displacing active immune cells and we need techniques for killing off the senescent cells. Imagine a machine that is analogous to a kidney dialysis machine that is specialized at separating senescent T cells from blood. If these old cells could simply be removed from the body the remaining T cells that retain the ability to divide could fill in the space made available by the removal of the senescent immune cells. Or perhaps a gene therapy could instruct senescent cells to commit cell suicide (apoptosis).

A rejuvenated immune system might itself kill off other senescent cell types. So methods to rejuvenate the immune system will provide many rejuvenation benefits. Plus, r, a younger immune system would probably reduce the incidence of cancer.

Share |      Randall Parker, 2008 July 06 10:19 PM  Aging Immune System


Comments
rsilvetz said at July 7, 2008 9:16 AM:

Hmmm.... does not compute. Fails consistency check against other published literature. To wit:

We know that restoration of a youthful macro-environment results in restoration of performance in old mice. This suggests, categorically and unavoidably that the cells are NOT senescent (at least not prior to terminal aging) . I suppose to prove the case conclusively one would have to do young-mice/old-mice plasma exchange and measure immune function. But a priori I see no reason why stem cells of the immune system would be any different from other stem cells repairing muscle.

If they bothered to integrate each others literature they would realize its about 80% foo-barred macro-environment and 15% clonal deletions and 5% other/unknown. Certainly a testable hypothesis. (And in regards to the so-called senescent CD8 cells unless I misread somewhere, they actually didn't check telomere length -- they checked telomerase activity. Two radically different things.)

Tj Green said at July 8, 2008 5:34 PM:

A species is created from interactions with the environment and other species. If a species steps out of this predator prey arms race, then evolution would eventually end the aging process for that species. For us aging will end.

Chris said at July 25, 2008 1:43 PM:

One big problem in extrapolating from mice is that their immune system isn't driven by the same genetic bits as is the human immune system. See: http://www.marshallprotocol.com/view_topic.php?id=4142&forum_id=37&jump_to=89011#p89011

But, the basic idea is on track, though one bit is missing. Instead of 80% foobarred environment, try 90% chronic infection. Dr Marshall has identified the technique used by the bacteria to shutdown the immune system (by blocking the VitaminD nuclear receptor), and how to reverse that. Then a long term use of low dose antibiotics to slowly clear the infection, and the (now healthy) immune system puts things back in order.

A recent interview with an MP patient does support the idea that restoring health to the immune system will help prevent cacner. (see http://bacteriality.com/2008/07/18/interview24/)

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