positive regulation of activated T cell proliferation

Definition

Target type: biologicalprocess

Any process that activates or increases the rate or extent of activated T cell proliferation. [GOC:jl]

Positive regulation of activated T cell proliferation is a complex biological process that involves a series of intricate signaling events, ultimately leading to the expansion of activated T lymphocytes. This process is critical for mounting effective immune responses against pathogens and maintaining immune homeostasis.

Upon encountering their cognate antigen presented by antigen-presenting cells (APCs), naive T cells become activated. This activation triggers a cascade of intracellular signaling pathways that drive T cell proliferation, differentiation, and effector functions. The key signaling pathways involved include:

1. TCR signaling: Engagement of the T cell receptor (TCR) by antigen presented on MHC molecules initiates a signaling cascade involving several intracellular proteins, such as Lck, ZAP-70, and LAT. These proteins activate downstream signaling pathways, including the MAPK and PI3K pathways.

2. Costimulatory signaling: T cell activation also requires costimulatory signals delivered by APCs through molecules like CD28. CD28 binding to its ligands CD80 and CD86 on APCs amplifies TCR signaling and promotes T cell survival and proliferation.

3. Cytokine signaling: Activated T cells produce and respond to various cytokines, such as IL-2, IL-4, IL-7, and IL-15. These cytokines play crucial roles in T cell proliferation, survival, differentiation, and effector function.

The combined activation of these signaling pathways leads to the expression of various genes that promote T cell proliferation, including the transcription factor c-Myc and the cell cycle regulator cyclin D1. These proteins induce cell cycle progression, leading to DNA replication and cell division.

In addition to these signaling events, T cell proliferation requires the presence of essential nutrients, growth factors, and a suitable microenvironment. The interaction between T cells and APCs within the lymph nodes provides an optimal environment for T cell activation and proliferation.

Positive regulation of activated T cell proliferation is tightly controlled by a complex network of regulatory mechanisms. These mechanisms ensure that T cell responses are appropriate in magnitude and duration and prevent uncontrolled immune activation. Dysregulation of these regulatory mechanisms can lead to autoimmune diseases and other immune disorders.

The precise molecular mechanisms underlying positive regulation of activated T cell proliferation are still being elucidated. However, ongoing research provides valuable insights into the intricate signaling pathways and regulatory mechanisms governing T cell activation and expansion.'
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Proteins (7)

Compounds (24)