CD25⁺regulatory T cells can be used therapeutically in collagen-induced arthritis

Naturally occurring CD4⁺CD25⁺ T cells have been shown to suppress immune responses both in vivo and in vitro. Finding a way to harness their regulatory abilities is of particular value in both transplantation and autoimmunity, where unwanted immune reactions need to be eliminated. Tantalizing evidence for their future potential is demonstrated by their ability to cure T cell mediated colitis induced in SCID mice [1]. However, many autoimmune diseases display a strong humoral component, such as rheumatoid arthritis. It is unknown whether CD4⁺CD25⁺ T cells are effective in these B cell-mediated autoimmune diseases.

We tested the ability of CD4⁺CD25⁺ T cells to modulate collagen-induced arthritis (CIA), a disease dependent on the presence of B cells [2].

In order to determine the role of endogenous CD25⁺ T cells in CIA, CD25⁺ cells were first depleted in mice before immunizations to induce CIA. The therapeutic value of these cells was assessed by adoptively transferring preactivated CD4⁺CD25⁺ T cells into mice during the onset of disease.

Depletion of CD25⁺ cells before CIA induction lead to a hastened severe disease in comparison with nondepleted control mice. If CD4⁺CD25⁺ T cells were transferred to mice therapeutically, the mice had a significantly milder disease.

CD4⁺CD25⁺ T cells can treat chronic arthritis and probably have the potential to treat a wide spectrum of autoimmune diseases, including those that are mainly mediated by B cells.