From the Guidelines
The answer is (a) transforming growth factor-β, as it is a potent inhibitor of T cell proliferation, playing a crucial role in immune regulation and tolerance. TGF-β functions by suppressing T cell activation, proliferation, and differentiation through multiple mechanisms, including inhibiting IL-2 production and signaling, which is essential for T cell growth, as seen in studies such as 1. It also blocks cell cycle progression by inducing cyclin-dependent kinase inhibitors and downregulating c-myc expression. Additionally, TGF-β promotes the development of regulatory T cells that further suppress immune responses. Unlike the other growth factors listed, which primarily stimulate cell growth in various tissues, TGF-β has distinct immunosuppressive properties that make it important in preventing excessive immune responses and autoimmunity. This cytokine is critical for maintaining immune homeostasis and is often dysregulated in autoimmune diseases and cancer, with recent studies like 1 highlighting its role in oncogenesis through dysregulation of cellular processes. Key points about TGF-β include:
- Its role in immune regulation and tolerance
- Its ability to suppress T cell activation, proliferation, and differentiation
- Its promotion of regulatory T cells
- Its distinct immunosuppressive properties
- Its critical role in maintaining immune homeostasis
- Its dysregulation in autoimmune diseases and cancer, as noted in 1.
From the Research
T Cell Proliferation Inhibitors
- A potent inhibitor of T cell proliferation is transforming growth factor-β (TGF-β) 2, 3, 4.
- TGF-β regulates thymic T-cell selection and maintains homeostasis of the naïve T-cell pool 2.
- It inhibits cytotoxic T lymphocyte (CTL), Th1-, and Th2-cell differentiation while promoting peripheral (p)Treg-, Th17-, Th9-, and Tfh-cell generation 2, 4.
- TGF-β also controls the proliferation, survival, activation, and differentiation of B cells, as well as the development and functions of innate cells 2, 3.
- The correct answer is (a) transforming growth factor-β, as it has been shown to inhibit T cell proliferation in various studies 2, 3, 4.
Other Options
- Platelet-derived growth factor (option b) is not mentioned as a potent inhibitor of T cell proliferation in the provided studies.
- Epidermal growth factor (option c) is not mentioned as a potent inhibitor of T cell proliferation in the provided studies.
- Basic fibroblast growth factor (option d) is not mentioned as a potent inhibitor of T cell proliferation in the provided studies.