One-Time Treatment Could Revitalize Immune Systems in the Elderly
PALO ALTO, Calif. — A new study suggests that a one-time treatment that modulates the composition of a type of immune cell could potentially revitalize the immune systems of the elderly, helping their bodies better react to viral and bacterial threats.
The research was carried out at Stanford University School of Medicine and published in the March 27 issue of the journal Nature.
During the study, Stanford researchers targeted the hematopoietic stem cells, or HSCs, in mice between 18 and 24 months old.
Hematopoietic stem cells give rise to all the other types of blood and immune cells including B and T cells, which are collectively known as lymphocytes.
As people age, HSCs begin to favor the production of other immune cells called myeloid cells over lymphocytes, hampering our body’s ability to fully react to new threats and weakening its response to vaccinations.
What the researchers found was that the mice in the study that were treated with an antibody targeting the myeloid-leaning HSCs for destruction had more of the balanced HSCs, and more new, naïve B and T lymphocytes, than their untreated peers even several weeks later.
“This is a real paradigm shift — researchers and clinicians should think in a new way about the immune system and aging,” said postdoctoral scholar Jason Ross, M.D., Ph.D., in an interview published on the Stanford School of Medicine website.
“The idea that it’s possible to tune the entire immune system of millions of cells simply by affecting the function of such a rare population is surprising and exciting,” he said.
Ross and Lara Myers, Ph.D., a research fellow at Rocky Mountain Laboratories, were the lead authors of the study.
Irving Weissman, M.D., professor of pathology and of developmental biology, and Kim Hasenkrug, Ph.D., the chief of Rocky Mountain Laboratories’ Retroviral Immunology Section, were the senior authors of the research.
“Not only did we see a shift toward cells involved in adaptive immunity, but we also observed a dampening in the levels of inflammatory proteins in the treated animals,” Ross continued. “We were surprised that a single course of treatment had such a long-lasting effect. The difference between the treated and untreated animals remained dramatic even two months later.”
When the treated mice were vaccinated eight weeks later against a virus they hadn’t encountered before, their immune systems responded more vigorously than those in untreated mice, and they were significantly better able to resist infection by that virus.
“Every feature of an aging immune system — functional markers on the cells, the prevalence of inflammatory proteins, the response to vaccination and the ability to resist a lethal infection — was impacted by this single course of treatment targeting just one cell type,” Ross said in the Stanford interview.
The exciting news for humans is that the researchers were able to show that mouse and human myeloid-biased HSCs are similar enough that it may one day be possible to use a similar technique to revitalize aging human immune systems.
“We believe that this study represents the first steps in applying this strategy in humans,” Ross told the reporter with the Stanford communications department.
Dan can be reached at [email protected] and @DanMcCue
