Regulatory T Cells

For many years, different laboratories — usually using different protocols — have found evidence of lymphocytes that suppress immune responses: antibody-mediated and/or cell-mediated. But these cells have been difficult to study, primarily because of the difficulty is isolating clones; that is, populations descended from a single cell.

Originally called suppressor T cells (Ts cells), the most promising recent candidates are now called regulatory T cells (Treg).

Treg Cells

Most CD4+ T cells belong to one or another of the helper T cell subsets [Link to discussion]. However ~10% of them do not. These so-called T-regulatory (Treg) cells

Treg cells respond to the presence of interleukin-2 (IL-2) by rapid proliferation [Link]. Because IL-2 is secreted by effector T cells, this provides a negative-feedback mechanism: inflammatory T-cell activity (e.g., by Th1 cells) is restrained by the resulting expansion of Treg cells.

Treg Subsets

There are two sources of Treg cells in the body:

Thymic Treg Cells (tTreg)

Many of the antigenic peptides recognized by the TCRs of tTreg cells are self-peptides and probably a major function of these cells is to inhibit other T cells from mounting an immune attack against self components; that is, to protect the body against autoimmunity.

This idea receives support from these observations:

Peripheral Treg Cells (pTreg)

Peripheral Treg cells develop from CD4+ T cells that, after binding antigen with their TCR, have been stimulated by TGF-β and retinoic acid [Link]. pTreg cells are abundant at mucosal surfaces that separate the external from the internal environment:

Further research will be needed to sort out the relationships between these and other T cells that suppress immune responses. This work will be important because it could lead to improvements in

Clinical trials of Treg cells are underway for all these conditions.

Welcome&Next Search

14 May 2013