monocyte aggregation

Definition

Target type: biologicalprocess

The adhesion of one monocyte to one or more other monocytes via adhesion molecules. [GOC:sl, PMID:12972508]

Monocyte aggregation is a complex process involving the recruitment, adhesion, and clustering of monocytes, a type of white blood cell, at sites of inflammation or injury. This process is crucial for initiating and orchestrating the inflammatory response, which is essential for tissue repair and defense against pathogens. Here's a detailed description of the biological process:

1. **Chemoattraction:** Monocytes are attracted to the site of inflammation by a range of chemoattractants, including chemokines (e.g., CCL2, CCL3, CCL5), complement components (e.g., C5a), and other inflammatory mediators. These chemoattractants bind to specific receptors on the monocyte surface, triggering intracellular signaling pathways that activate cell migration.

2. **Adhesion:** As monocytes approach the site of inflammation, they adhere to the endothelium, the inner lining of blood vessels. This adhesion is mediated by a variety of adhesion molecules, including selectins (e.g., L-selectin, P-selectin, E-selectin), integrins (e.g., LFA-1, Mac-1), and immunoglobulin superfamily molecules (e.g., ICAM-1, VCAM-1).

3. **Diapedesis:** Once adhered, monocytes undergo a process called diapedesis, where they squeeze through the gaps between endothelial cells and enter the inflamed tissue. This process is facilitated by the action of chemokines and other inflammatory mediators that alter the structure and permeability of the endothelial barrier.

4. **Aggregation:** Once in the inflamed tissue, monocytes interact with each other and with other immune cells, such as neutrophils and macrophages. This interaction is mediated by a variety of cell adhesion molecules and signaling pathways. Monocytes may also interact with components of the extracellular matrix, such as collagen and fibronectin, which further contributes to their aggregation.

5. **Differentiation and Activation:** As monocytes aggregate at the site of inflammation, they differentiate into macrophages or dendritic cells, depending on the specific microenvironment. These differentiated cells are highly phagocytic and secrete a variety of inflammatory mediators, including cytokines (e.g., TNF-α, IL-1β, IL-6) and chemokines. These mediators further amplify the inflammatory response and contribute to the recruitment and activation of other immune cells.

The aggregation of monocytes is a highly regulated process that is essential for the proper functioning of the immune system. Disruptions in this process can lead to a variety of inflammatory diseases, including atherosclerosis, rheumatoid arthritis, and inflammatory bowel disease.'
"

Proteins (2)

Compounds (3)