Metformin may help make vaccines work better: study

* Mice given the drug made more immune system cells

* Drug could be used with cancer or other vaccines

CHICAGO (Reuters) - A common diabetes pill may help trick the body into making more powerful immune system cells that could help make vaccines and cancer treatments work better, U.S. and Canadian researchers said on Wednesday.

When they gave the drug metformin to mice, they made more of a type of immune system memory cell that can recognize infections or respond to vaccinations.

“Our findings were unanticipated, but are potentially extremely important and could revolutionize current strategies for both therapeutic and protective vaccines,” Yongwon Choi of the University of Pennsylvania, whose study appears in the journal Nature, said in a statement.

Choi and colleagues said they may be able to use the drug in non-diabetics to boost the body’s response to vaccines or new cancer treatments that rely on the immune system to fight tumors.

In diabetics, metformin works by stimulating AMP-activated protein kinase or AMPK, a master circuit for energy metabolism in the body.

“What happens in diabetics is this circuit is broken,” Russell Jones of McGill University in Canada, who worked on the study, said in a telephone interview.

Jones said metformin works in part by tricking the body into thinking it is starving, activating the AMPK circuit.

The team wanted to see how this same energy metabolism circuit affects white blood cells of the immune system known as memory T-cells.

Jones describes them as a special group of sentinels left behind after the army has left a battle.

“It’s like the guys guarding the fort. They’ve seen the enemy and they know what is is,” Jones said.

Jones said when they body makes memory-T cells, it uses some of the same energy metabolism circuits.

“This is where metformin comes in,” Jones said.

The team gave the drug to mice that lacked a gene needed to make memory T-cells.

“To our surprise, we completely rescued the memory cell defect in these mice,” Jones said. And when they gave metformin to normal mice, they actually made more memory T-cells.

“When we give metformin, it’s like giving the T-cell response a boost,” he said.

Jones said the findings would need to be studied in humans, but he thinks it may be possible to use metformin to help routine vaccines work better, and it may even help strengthen the immune system’s response to vaccines being developed to fight cancer.

Metformin is used to treat type 2 diabetes, which linked to a poor diet and lack of exercise and accounts for about 90 percent of all diabetes cases.

The International Diabetes Federation estimates more than 380 million people will have a form of diabetes by 2025.

Editing by Maggie Fox and Cynthia Osterman