T-helper 17 cell chemotaxis

Definition

Target type: biologicalprocess

The directed movement of a T-helper 17 cell in response to an external stimulus. [CL:0000899, GOC:BHF]

T-helper 17 (Th17) cell chemotaxis is a complex process that involves the directed migration of Th17 cells towards a chemical gradient. This process is crucial for the immune response to pathogens, particularly in the context of mucosal immunity.

Here's a detailed description of the process:

**1. Initiation of Chemotaxis:**

* **Pathogen Recognition:** Th17 cells express various receptors, including Toll-like receptors (TLRs) and cytokine receptors, that recognize pathogen-associated molecular patterns (PAMPs) from bacteria, fungi, and other pathogens.
* **Cytokine Production:** Upon PAMP recognition, Th17 cells produce pro-inflammatory cytokines like interleukin-17 (IL-17), IL-22, and TNF-α. These cytokines play a critical role in initiating the inflammatory response and recruiting other immune cells to the site of infection.
* **Chemokine Release:** Pathogens and host cells at the infection site release chemokines, such as CCL20, CCL2, and CXCL8. These chemokines act as chemoattractants for Th17 cells.

**2. Chemokine Sensing and Signaling:**

* **Chemokine Receptor Binding:** Th17 cells express chemokine receptors, including CCR6, CCR2, and CXCR1, which bind to specific chemokines. This binding activates intracellular signaling pathways.
* **Signal Transduction:** Chemokine receptor activation triggers a cascade of signaling events involving G proteins, phospholipase C, and calcium release. These events lead to changes in cell polarization and cytoskeletal rearrangements.

**3. Cell Polarization and Migration:**

* **Polarization:** The signaling cascade directs the assembly of the cell's cytoskeleton, leading to polarization of the cell. One end of the cell, the leading edge, extends towards the chemokine gradient.
* **Motility:** The polarized cell utilizes actin polymerization and myosin motor proteins to generate force, allowing it to move towards the chemokine source.
* **Chemotaxis:** This directed movement of Th17 cells along the chemokine gradient is known as chemotaxis.

**4. Th17 Cell Accumulation and Function:**

* **Immune Response:** Th17 cells migrate to the site of infection, where they release pro-inflammatory cytokines and recruit other immune cells, such as neutrophils and macrophages. This inflammatory response helps to clear the pathogen.
* **Tissue Repair:** After infection, Th17 cells contribute to tissue repair and restoration of homeostasis.

**5. Regulation of Chemotaxis:**

* **Immune Tolerance:** Mechanisms exist to regulate Th17 cell chemotaxis and prevent excessive inflammation. These mechanisms involve negative feedback loops, regulatory T cells, and other immune mediators.

In summary, Th17 cell chemotaxis is a tightly regulated process that involves pathogen recognition, chemokine signaling, cell polarization, and directed migration. This process is essential for the immune response against pathogens, particularly in mucosal tissues.'
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Proteins (1)

Compounds (19)