Study provides insight into aging immune systems

March 14, 2011, Loyola University Health System

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 ."

Related Stories

Recommended for you

The HLF gene protects blood stem cells by maintaining them in a resting state

January 17, 2018
The HLF gene is necessary for maintaining blood stem cells in a resting state, which is crucial for ensuring normal blood production. This has been shown by a new research study from Lund University in Sweden published in ...

Magnetically applied MicroRNAs could one day help relieve constipation

January 17, 2018
Constipation is an underestimated and debilitating medical issue related to the opioid epidemic. As a growing concern, researchers look to new tools to help patients with this side effect of opioid use and aging.

Researchers devise decoy molecule to block pain where it starts

January 16, 2018
For anyone who has accidentally injured themselves, Dr. Zachary Campbell not only sympathizes, he's developing new ways to blunt pain.

Scientists unleash power of genetic data to identify disease risk

January 16, 2018
Massive banks of genetic information are being harnessed to shed new light on modifiable health risks that underlie common diseases.

Blood-vessel-on-a-chip provides insight into new anti-inflammatory drug candidate

January 15, 2018
One of the most important and fraught processes in the human body is inflammation. Inflammatory responses to injury or disease are crucial for recruiting the immune system to help the body heal, but inflammation can also ...

Molecule produced by fat cells reduces obesity and diabetes in mice

January 15, 2018
UC San Francisco researchers have discovered a new biological pathway in fat cells that could explain why some people with obesity are at high risk for metabolic diseases such as type 2 diabetes. The new findings—demonstrated ...

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.