About CXCL9 / MIG:
Chemokine (C-X-C motif) ligand 9 also known as CXCL9, is a small cytokine that belongs to the CXC chemokine family, also named as Monokine induced gamma interferon. CXCL9 is a T-cell chemoattractant, which can be induced by IFN-y. This gene is very closely related to two other CXC chemokines, called CXCL10 and CXCL11 - both of these genes are located near to the gene for CXCL9 in human chromosome 4. CXCL9, CXCL10, and CXCL11 all stop the chemotactic functions by interacting with CXCR3, the chemokine receptor.
Chemokines are a family of smaller cytokines - signaling proteins that are secreted by the cells. These cells get their names from the fact that they are able to induce directed chemotaxis within nearby cells that are responsive - these are known as chemotactic cytokines. Cytokine proteins are classed as ‘cytokines’ due to how they behave and also due to the structural characteristics that they have. In addition, they are known for monitoring chemotaxis, mediating where needed. Chemokines are around 8-10 kilodaltons in mass and usually have four cysteine residues kept in conserved locations, it’s these that allow them to form their three dimensional shape.
A higher percentage of chemokines are pro-inflammatory and can be induced when an immune response in ongoing, to recruit cells from the immune system to the place of infection. Of course, not all chemokines are the same - other chemokines are considered homeostatic, and focus on controlling the movement of cells during ‘normal’ processes to do with tissue, such as maintenance and development. These are found within the vertebrates, as well as in some viruses and bacteria.
Chemokines are classified in four main subfamilies, these are CXC, CC, CX3C, and XC. Each of these proteins take their proteins from biological effects by interacting with g-protein linked transmembrane receptors known as chemokine receptors - these are found on the surface of target cells.
CXCL9 is degraded by neutrophil collagenase / matrix metalloproteinase 8 (MMP-8) and can cleave CXCL10 at two specific positions. While gelatinase B/matrix metalloproteinase 9 (MMP-9) can degrade CXCL10 and can cleave CXCL9 at three different areas in its extended carboxy-terminal region.
CXCL9, -10, -11 have been proven to be valid biomarkers for the development of heart failure and left ventricular dysfunction, which can suggest a potentially underlying pathophysiological relation between the levels of these chemokines and the development of adverse cardiac remodeling.
This specific chemokine has been associated as a potential market for diagnosing Q fever infections. Q fever, also known as query fever, is a bacterial infection that is caused by Coxiella burnetii, a bacteria that is found in cows, sheep, and goats.
Normally, humans contract Q fever when they breathe in dust that has been contaminated by infected animals. Farmers, veterinary specialists, and people that work in laboratories are at the highest risk, due to the circumstances in which they work.
Usually, the highest amount of infection is found in birth products, such as the placenta, for instance. This disease normally causes mild symptoms similar to those of the flu and clears up on its own. However, in rare cases, a more serious form of the disease develops and becomes chronic.