|
E-mail this page to a friend!
Immune System Boost May Lead to Cancer Vaccines
Mayo Clinic says boosting output of immune cells also
protects elderly
Sept. 26, 2005 - Mayo Clinic researchers have
discovered a way to dramatically boost the output of immune system cells
from the thymus, which may lead to improved cancer vaccines, as well as
to ways to otherwise strengthen immune responses. Older people, too,
experienced the increased disease fighting ability.
| |
Related Stories |
|
| |
Senior Citizens Worst In Spotting Cancer Myths
One quarter of Americans believe cancer cure is being
withheld by industry
June 27, 2005 – Senior citizens are the worst
informed about cancer, according to an American Cancer Society survey
that found up to half of all Americans mistakenly believe surgery can
spread cancer, and more than one in four thinks a cure for cancer
already exists but is being held back by a profit-driven industry.
Read more...
|
|
The Mayo report appears in the current online
edition of the journal
AIDS (link opens in new window). Mayo Clinic scientists studied the
immune system responses in blood samples from health care workers
accidentally exposed to HIV, who then received a commonly used anti-AIDS
treatment known as antiretroviral therapy (ART). None of the workers
developed HIV infections.
In these non-HIV-infected test subjects, the
scientists discovered that ART dramatically increases (up to a factor of
1,000) the production of cells from which the immune system makes
disease-attacking T cells. Importantly, the increase in T cells also
occurred in older people who generally produce few new T cells. Further
experiments were performed in mice to see if the ART treatment caused
the immune system to erroneously attack the host instead of disease
agents. It did not.
Significance of the Mayo Clinic Research
The findings are significant because they suggest
new ways to use an existing and approved drug regimen of ART to
stimulate the thymus to produce more T cells -- without provoking an
"autoimmune" reaction in which the body attacks itself. T cells are
major disease fighters of the immune system that are depleted in
diseases such as AIDS and cancers, as well as in bone marrow transplant
recipients. ART is a combination treatment of antiretroviral drugs and
drugs that prevent cell death.
Possible Applications
"One of the potential uses we envision is to use
the ART treatment as a way to use tumor components to immunize cancer
patients against their own cancer cells," explains Mayo Clinic
immunologist David McKean, Ph.D. "The current problem with this
treatment strategy is that the tumor gives off a variety of soluble
products which we don't fully understand, but which we know wreck havoc
on the immune system by suppressing its various components. If we can
use the ART drugs to increase the number of newly produced T cells in
cancer patients first, we can potentially improve the likelihood of
getting a cancer vaccine to work."
The findings may also benefit the aging population.
"The ability of ART to boost T cell numbers may
allow patients who normally don't respond to vaccines - such as those
with chronic disease, or the elderly - to mount an effective immune
response if they receive the vaccination in combination with ART," says
co-author and Mayo Clinic immunologist Andrew Badley, M.D.
With age the thymus (located in the upper chest)
diminishes and produces fewer T cells. This leaves the elderly more
vulnerable to disease and less able to make effective use of vaccines.
However, researchers say if the aging immune system was primed by the
ART regimen prior to receiving vaccines, a stronger immune response
might be provoked. That way people might be better protected, and public
health officials could use their supplies of vaccine more effectively.
About the Investigation
In the seven participants treated with ART, five
showed a dramatic increase in a specific kind of cell known as "naive T
cells". This is important because naive T cells are used by the body to
destroy tumor cells or cells that have been infected by viruses to which
the individual has not been previously exposed. Says Dr. McKean, "A
person in their 60s doesn't produce many new T cells. Yet in order to
effectively respond to a pathogen you haven't seen before, you really
need those new T cells produced by the thymus. So that's why as people
get older they become more susceptible to particular viruses."
Collaboration and Support
In addition to Drs. McKean and Badley, the Mayo
Clinic research team included Daniel Graham, Ph.D.; Michael P. Bell;
Catherine Huntoon; Joel Weaver; and Nanci Hawley. Their work was
supported by grants from the National Institutes of Health and the
Burroughs Wellcome Translational Research Award.
Click to More Senior News on the
Front Page
Copyright: SeniorJournal.com |
