Viruses may be targeting a new immunological system uncovered by biomedical experts in hens. The discovery, which has ramifications for other bird diseases, gives more information on birds’ immune responses to zoonotic viruses, specifically how those responses may differ from those seen in humans.
Researchers discovered that several internal defense systems that are dormant in rural birds are significantly more active in urban birds. These biological pathways are producing more antioxidants, immune system cells, and detoxifiers, indicating that city life is putting a strain on their health.
A research team lead by a biomedical scientist at the University of California, Riverside has uncovered a novel immunological route in chickens that viruses may be targeting, such as those that infect birds, humans, and animals and spread diseases like influenza or Crimean-Congo hemorrhagic fever. The discovery, which has ramifications for other bird diseases, gives more information on birds’ immune responses to zoonotic viruses, specifically how those responses may differ from those seen in humans.
We discovered that chicken OASL possesses properties similar to those observed in mammalian ISG15s. Our examination of OASL sequences from six different bird species suggests that these characteristics are likely shared throughout avian OASLs.
Professor Scott Pegan
City wildlife encounters different predators, food availability, and diseases than rural animals. This may be beneficial to them, since humans, for example, leave food out for birds in their gardens. They must also contend with a fragmented habitat as well as noise, air, and light pollution. Scientists want to understand these processes so they can better comprehend the significant decline in some bird species.
“Understanding these distinctions is crucial to better understanding birds as possible reservoirs of human diseases,” said Scott Pegan, a biomedical sciences professor at the University of California, Riverside, who led the study, which was published in Frontiers in Immunology. “It also allows researchers to gain a better understanding of the immunological processes that may lead to useful vaccinations for agricultural usage in poultry.”
ISG15, a protein found in birds’ cells, is missing. ISG15, which is found in mammals and other non-avian reptiles, aids in the mounting of an efficient immune response to viral infection. ISG15 functions as a messenger molecule, assisting in the stabilization of host and viral proteins as well as the regulation of several antiviral responses. Birds, on the other hand, have OASL proteins that aid in the production of a powerful immune response to viral infection. Pegan and his team focused on chicken immunity.
“We discovered that chicken OASL possesses properties similar to those observed in mammalian ISG15s,” Pegan explained. “Our examination of OASL sequences from six different bird species suggests that these characteristics are likely shared throughout avian OASLs.”
The researchers discovered that avian OASLs include an amino acid sequence motif, LRLRGG, within what is known as a ubiquitin-like domain. This motif enables OASL to bind to other host proteins and drive certain host antiviral processes.
“This has never been presented before,” stated Pegan. “We discovered that OASL in birds has this peculiar LRLRGG motif at one end, which is quite useful. Furthermore, the area of the protein to which this motif belongs has a similar 3D atomic structure to ISG15. This, together with results about what it can adhere to within cells, suggests that OASL serves at least a portion of the role that ISG15 would have played in birds.”
Pegan noted that in order to inhibit the human immune system, viruses have a protein that does two things: it removes ISG15 as well as ubiquitin, which is a tiny protein that helps regulate the activities of other proteins in the body from host and viral proteins. OASLs are four times larger than these tiny proteins, with various sections performing different tasks. Although mammals contain OASL proteins, they lack this extra domain for conjugation to other proteins, implying that birds evolved to centralize activities carried out by ISG15 and other immunological pathways. Pegan’s team uncovered this immunological pathway in birds that functions as a replacement for ISG15.
City wildlife encounters different predators, food availability, and diseases than rural animals. This may be beneficial to them, since humans, for example, leave food out for birds in their gardens. They must also contend with a fragmented habitat as well as noise, air, and light pollution. Scientists want to understand these processes so they can better comprehend the significant decline in some bird species.
“We’ve discovered a novel immunological mechanism in hens,” he stated. “Viruses appear to be evolutionarily programmed to try to obstruct this pathway. Such knowledge enables us to create better vaccinations and therapies that aim to optimize the activation of this pathway in order to assist chickens to fight sickness. It also allows animal husbandry programs to further enhance this pathway’s potency leading to poultry that is more resistant to disease.”
