The research team further zeroed in on a class of cells known as regulatory T cells, whose main function is keeping tabs on other immune cells to ensure they don't turn against the body's own tissues. When researchers compared the number of regulatory T cells present in the spleens of male and female mice, they noticed far fewer regulatory T cells in the spleens of female mice. The spleen, the researchers explain, is the primary residence of mature immune cells.
"Deficiency of regulatory T cells effectively takes the reins off other immune cells, leading to overactive immunity," Njoku says.
In a final, dot-connecting move, the researchers immersed spleen-derived immune cells in estrogen. What they observed proved beyond doubt that estrogen, interleukin and regulatory T cells form a powerful triangle. Estrogen induced the immune cells of female mice to express more interleukin-6, which in turn diminished the expression of inflammation-taming regulatory T cells.
When the researchers injected sick female mice with a booster dose of regulatory T cells, their liver inflammation subsided to levels seen in male mice.
This powerful response, the researchers say, suggests that therapy with regulatory T cells may reduce estrogen-related liver damage in patients with autoimmune hepatitis. Such treatment, however, remains years away from human application.
One reason, the researchers say, is that regulatory T cells maintain the fine equilibrium between overactive and underactive immunity. Because an overactive immune system can lead to autoimmune diseases and an underactive one can promote tumor growth, any therapy with regulatory T cells mus
|Contact: Ekaterina Peshva|
Johns Hopkins Medicine