Evasins are a family of salivary
protein
Proteins are large biomolecules and macromolecules that comprise one or more long chains of amino acid residues. Proteins perform a vast array of functions within organisms, including catalysing metabolic reactions, DNA replication, respo ...
s produced in parasitic
tick
Ticks (order Ixodida) are parasitic arachnids that are part of the mite superorder Parasitiformes. Adult ticks are approximately 3 to 5 mm in length depending on age, sex, species, and "fullness". Ticks are external parasites, living by ...
s which are capable of shutting off the first steps of an immune response brought about by
chemokine
Chemokines (), or chemotactic cytokines, are a family of small cytokines or signaling proteins secreted by cells that induce directional movement of leukocytes, as well as other cell types, including endothelial and epithelial cells. In additio ...
s.
These proteins are injected into a
tick
Ticks (order Ixodida) are parasitic arachnids that are part of the mite superorder Parasitiformes. Adult ticks are approximately 3 to 5 mm in length depending on age, sex, species, and "fullness". Ticks are external parasites, living by ...
's host to prevent a painful inflammation that might otherwise alert the host to the tick's presence. As chemokines have been implicated in a number of
inflammatory disease
Inflammation (from la, inflammatio) is part of the complex biological response of body tissues to harmful stimuli, such as pathogens, damaged cells, or irritants, and is a protective response involving immune cells, blood vessels, and molecu ...
s including
atherosclerosis
Atherosclerosis is a pattern of the disease arteriosclerosis in which the wall of the artery develops abnormalities, called lesions. These lesions may lead to narrowing due to the buildup of atheroma, atheromatous plaque. At onset there are usu ...
,
asthma
Asthma is a long-term inflammatory disease of the airways of the lungs. It is characterized by variable and recurring symptoms, reversible airflow obstruction, and easily triggered bronchospasms. Symptoms include episodes of wheezing, cou ...
,
rheumatoid arthritis
Rheumatoid arthritis (RA) is a long-term autoimmune disorder that primarily affects joints. It typically results in warm, swollen, and painful joints. Pain and stiffness often worsen following rest. Most commonly, the wrist and hands are involv ...
, and
cancer
Cancer is a group of diseases involving abnormal cell growth with the potential to invade or spread to other parts of the body. These contrast with benign tumors, which do not spread. Possible signs and symptoms include a lump, abnormal b ...
, chemokine-binding proteins such as evasins are being researched to assess their therapeutic potential as chemokine-targeting antagonists.
The same term is also used to refer to other proteins.
Tick evasins
The
brown dog tick
''Rhipicephalus sanguineus'', commonly called the brown dog tick, kennel tick, or pantropical dog tick, is a species of tick found worldwide, but more commonly in warmer climates. This species is unusual among ticks in that its entire lifecycle ...
evasin-4 binds to
CCL5
Chemokine (C-C motif) ligand 5 (also CCL5) is a protein which in humans is encoded by the ''CCL5'' gene. The gene has been discovered in 1990 by ''in situ'' hybridisation and it is localised on 17q11.2-q12 chromosome. It is also known as RANTES ...
and
CCL11
C-C motif chemokine 11 also known as eosinophil chemotactic protein and eotaxin-1 is a protein that in humans is encoded by the CCL11 gene. This gene is encoded on three exons and is located on chromosome 17.
Function
CCL11 is a small cytokine ...
, but appears to neutralize even more chemokines.
It has an
Ig-fold domain. Other evasins in this organism include Evasin-1 () and Evasin-3 ().
Other evasins
Evasin is also used to refer to any viral proteins used for the evasion of the immune responses. This usage is rare.
The term is also used to refer to "Endogenous VASopeptidase INhibitors" (), a kind of endogenous brain protein found in snakes.
References
{{reflist
Proteins