Regulatory T cells, commonly known as
Tregs, are a specialized subpopulation of T cells that play a crucial role in maintaining immune homeostasis and tolerance to self-antigens. These cells are essential for preventing autoimmune diseases and controlling excessive immune responses that can lead to tissue damage.
In histological studies, Tregs can be identified by their unique markers. The most widely recognized markers for Tregs are
CD4,
CD25, and the transcription factor
FoxP3. Immunohistochemistry (IHC) and immunofluorescence are commonly used techniques to visualize these markers in tissue sections. By staining for these markers, researchers can specifically identify and study Tregs within various tissues.
Tregs are predominantly found in lymphoid tissues such as the
thymus,
spleen, and
lymph nodes. However, they can also be located in non-lymphoid tissues including the
skin,
gut, and
lungs. Their distribution across various tissues highlights their importance in regulating immune responses throughout the body.
Tregs contribute to tissue homeostasis by suppressing the activation and proliferation of autoreactive T cells and other immune cells that can cause tissue damage. They produce inhibitory cytokines such as
IL-10 and
TGF-β, which help in modulating the immune response. Additionally, Tregs can directly interact with dendritic cells and other antigen-presenting cells to diminish their ability to activate effector T cells.
The development of Tregs primarily occurs in the thymus, where precursor T cells expressing high-affinity T-cell receptors for self-antigens are induced to become Tregs. This process is known as
thymic selection and is crucial for establishing central tolerance. Tregs can also differentiate from conventional T cells in the periphery through a process called peripheral induction, especially under the influence of immunosuppressive cytokines.
The absence or dysfunction of Tregs is closely associated with the development of autoimmune diseases such as
type 1 diabetes,
multiple sclerosis, and
rheumatoid arthritis. In these conditions, the immune system mistakenly attacks the body’s own tissues. Adequate Treg function is essential to prevent such autoreactive immune responses and maintain immune tolerance.
Given their pivotal role in immune regulation, Tregs represent a promising target for therapeutic interventions. Strategies to enhance Treg function could be beneficial for treating autoimmune diseases, while methods to inhibit Tregs might improve anti-tumor immunity in cancer therapy. Currently, research is ongoing to develop Treg-based therapies such as Treg expansion and adoptive Treg transfer for clinical applications.
