Study provides insight into aging immune systems

Mar 14, 2011

A study featured on the cover of the March 15 Journal of Immunology is providing insight into why the elderly are so vulnerable to pneumonia and other bacterial infections.

Compared with younger adults, the elderly are at higher risk of becoming seriously ill or dying from . Moreover, vaccines against the disease are less effective in the elderly.

To help understand why, Loyola researchers examined two types of , macrophages and B cells, located in specialized areas in the spleens of mice. (Macrophages gobble up bacteria, while B cells produce antibodies that fight bacteria.)

Macrophages and B cells appeared to be just as effective in old mice as they were in younger mice. But there were fewer of them.

"If we knew how to replenish these cells, we might be able to lower the risk of bacterial infections in the elderly," said senior author Pamela Witte, a professor in the Department of Microbiology and Immunology at Loyola University Chicago Stritch School of Medicine. "This is an unexplored area in aging."

The finding also could provide clues to developing vaccines against pneumococcal pneumonia that would be more effective in the elderly, said first author Shirin Birjandi, who is completing her PhD at Loyola.

For example, Birjandi said, current vaccines instruct B cells to make antibodies against bacteria that cause pneumonia. But if humans are like mice, the elderly will have fewer B cells. So it might make more sense to develop vaccines that instead target other immune system cells, Birjandi said.

In their study, Loyola researchers examined and macrophages that form microscopic rings in the spleen called marginal zones. These marginal zones form protective rings, preventing bacteria from passing through.

Photographs taken by the researchers show that in the spleens of young mice, macrophages form distinct rings in the marginal zones. (One of these photos appears on the cover of the .) In old mice, however, the photographs show that marginal zone rings are dramatically disrupted. (In humans, the equivalent ages of the old mice would be between 70 and 80.)

Researchers wrote that understanding changes such as these "is important for developing more efficient therapies for preventing diseases, such as bacterial pneumonia, that have shown to be highly detrimental in the ."

Explore further: Goat to be cloned to treat rare genetic disorder

add to favorites email to friend print save as pdf

Related Stories

How Bacteria Boost the Immune System

Jun 11, 2010

(PhysOrg.com) -- Scientists have long known that certain types of bacteria boost the immune system. Now, Loyola University Health System researchers have discovered how bacteria perform this essential task.

Rejuvenating the old immune system

Jan 26, 2010

By comparing the immune responses of both, young and old mice, to bacterial infection they found that the number of macrophages, one of the major cell populations involved in the elimination of infecting bacteria, decreases ...

Scientists show how anthrax bacteria impair immune response

Nov 17, 2010

Researchers from the National Institute of Allergy and Infectious Diseases (NIAID), part of the National Institutes of Health, have determined a key mechanism by which Bacillus anthracis bacteria initiate anthrax infection despit ...

Brothers in arms

Mar 17, 2009

Influenza, or flu, is an unpleasant affair with fever, cough, as well as head and body ache. When this illness is further complicated by a bacterial pneumonia, a harmful super-infection develops. Until now, researchers thought ...

Recommended for you

Researchers transplant regenerated oesophagus

20 hours ago

Tissue engineering has been used to construct natural oesophagi, which in combination with bone marrow stem cells have been safely and effectively transplanted in rats. The study, published in Nature Communications, shows ...

User comments : 0

More news stories

ESO image: A study in scarlet

This new image from ESO's La Silla Observatory in Chile reveals a cloud of hydrogen called Gum 41. In the middle of this little-known nebula, brilliant hot young stars are giving off energetic radiation that ...

First direct observations of excitons in motion achieved

A quasiparticle called an exciton—responsible for the transfer of energy within devices such as solar cells, LEDs, and semiconductor circuits—has been understood theoretically for decades. But exciton movement within ...

Patent talk: Google sharpens contact lens vision

(Phys.org) —A report from Patent Bolt brings us one step closer to what Google may have in mind in developing smart contact lenses. According to the discussion Google is interested in the concept of contact ...

Warm US West, cold East: A 4,000-year pattern

Last winter's curvy jet stream pattern brought mild temperatures to western North America and harsh cold to the East. A University of Utah-led study shows that pattern became more pronounced 4,000 years ago, ...