Cytokines, Chemokines and Growth Factors
Understanding biology and disease processes is an incredible challenge. Cell-based assays focusing on signalling, function, morphology, to name but a few enable to get further insight in biology and disease. Cell-based assay is here referred to as any assay measuring or detecting effects, elements or parts of a living cell.
CellMade offers a broad range of Cytokines, Chemokines and Growth Factors Cell-based assays using both normal and diseased human primary cell models. All proposed CellMade cell models, culture media, reagents and services are thoroughly tested and guarantee optimal performance. The available cell-based assays can be used in a broad variety of experimental applications.
The inflammasome, a multiprotein oligomer, is responsible for the activation of inflammatory responses. The inflammasome promotes the maturation and secretion of pro-inflammatory cytokines. Problems with regulating inflammasomes have been linked to several diseases such as the metabolic syndrome and type II Diabetes. These diseases have been connected to either too much or too little secretion of pro-inflammatory cytokines induced by the inflammasome.
Cytokines are a broad category of small immunomodulating proteins (~5–20 kDa) that are important in cell signaling. Their release directly affects surrounding cells. Cytokines are important in health and disease, specifically in host responses to infection, immune responses and inflammation. Cytokines include chemokines, interferons, interleukins, lymphokines and tumor necrosis factors but generally not hormones or growth factors. Cytokines are produced by a broad range of cells, including immune cells like macrophages, B lymphocytes, T lymphocytes and mast cells, as well as endothelial cells, fibroblasts, and various stromal cells; one given cytokine may be produced by more than one type of cell. Cytokines act through receptors, and are especially important in the immune system, as they modulate the balance between humoral and cell-based immune responses. Furthermore, they regulate maturation, growth, and responsiveness of particular cell populations. Some cytokines enhance or inhibit the action of other cytokines in complex ways.
Each Cytokine has a matching cell-surface receptor. Subsequent cascades of intracellular signaling then alter cell functions. This may include the upregulation and/or downregulation of several genes and their transcription factors, resulting in the production of other cytokines, an increase in the number of surface receptors for other molecules, or the suppression of their own effect by feedback inhibition. The effect of a particular Cytokine on a given cell depends on the Cytokine, its extracellular abundance, the presence and abundance of the complementary receptor on the cell surface, and downstream signals activated by receptor binding; these last two factors can vary by cell type. Cytokines are characterized by considerable redundancy, in that many cytokines appear to share similar functions.
Cytokines are crucial for fighting off infections but as well in other immune responses. However, they can become dysregulated and pathological within inflammation. Adverse effects of cytokines have been linked to many diseases. Normal tissue integrity is preserved by feedback interactions between diverse cell types mediated by adhesion molecules and secreted cytokines. Disruption of normal feedback mechanisms threatens tissue integrity. Over-secretion of cytokines can trigger a dangerous syndrome known as a cytokine storm.
Chemokines are a broad category of small cytokines, or signaling proteins secreted by cells. Their name is derived from their ability to induce directed chemotaxis in nearby responsive cells; they are chemotactic cytokines. Cytokine proteins are classified as chemokines according to behavior and structural characteristics. In addition to being known for mediating chemotaxis, chemokines are all approximately 8-10 kilodaltons in mass and have four cysteine residues in conserved locations that are key to forming their 3-dimensional shape. Some chemokines are considered pro-inflammatory and can be induced during an immune response to recruit cells of the immune system to a site of infection, while others are considered homeostatic and are involved in controlling the migration of cells during normal processes of tissue maintenance or development. Chemokines exert their biological effects by interacting with G protein-linked transmembrane receptors called chemokine receptors, that are selectively found on the surfaces of their target cells.
Chemokines are functionally divided into two groups:
- Homeostatic: are constitutively produced in certain tissues and are responsible for basal leukocyte migration.
- Inflammatory: these are formed under pathological conditions: on pro-inflammatory stimuli and actively participate in the inflammatory response attracting immune cells to the site of inflammation.
A growth factor is a naturally occurring substance capable of stimulating cellular growth, proliferation, healing, and cellular differentiation. Usually it is a protein or a steroid hormone. Growth factors are important for regulating a variety of cellular processes. Growth factors typically act as signaling molecules between cells. Examples are cytokines and hormones that bind to specific receptors on the surface of their target cells. They often promote cell differentiation and maturation, which varies between growth factors. For example, epidermal growth factor (EGF) enhances osteogenic differentiation, while fibroblast growth factors and vascular endothelial growth factors stimulate blood vessel differentiation (angiogenesis). The term growth factor is sometimes used interchangeably with the term cytokine. While growth factor implies a positive effect on cell division, cytokine is a neutral term with respect to whether a molecule affects proliferation. While some cytokines can be growth factors, others have an inhibitory effect on cell growth or proliferation.
Plasma levels of various cytokines, chemokines and growth factors may give information on the presence, or even predictive value of inflammatory processes involved in metabolic disease such as NAFLD-NASH, T2DM, Cardiovascular Disease, as well as immunomodulatory effects of foods or drugs.
For further information on these assays and our standard experimental set-up, please download the CellMade Cytometry Assays – Technical Information and General Instructions leaflet.