A new study published in the American Journal of Physiology presents data suggesting that birds do not carry a specific anti-inflammatory protein critical for keeping inflammation under control in mammals, reptiles and amphibians.
The specific protein is tristetraprolin (TTP). It functions mainly by inhibiting key mediators of inflammation in the body, such as tumor necrosis factor alpha (TNFa). In fact, mice that are missing this protein have chronic systemic inflammation from unchecked TNFa. Moreover, mice missing the protein specifically in myeloid cells develop fatal inflammation from severely elevated TNFa when exposed to the pro-inflammatory chemical lipopolysaccharide.
Dr. Perry Blackshear and colleagues at the National Institute of Environmental Health Sciences searched for evidence of TTP in the genome of numerous species of birds. They came up empty-handed. The research team also attempted to stimulate the production of TTP by exposing cells from chickens to proteins from other animals as well as a molecule isolated from bacteria to no avail.
It is really interesting that birds do not seem to express this protein that is so vital to preventing inflammation in animals from other classes (mammalia, reptilia, and amphibia). In a press release from the American Physiological Society the study authors were quoted saying, “From an immunological standpoint, it will be both interesting and important to determine how birds cope differently with the environmental and microbiological assaults that stimulate the acute innate immune response in mammals. This will be important to understand, both to protect birds from infections, and to protect man from bird-transmitted” viruses.
Lai WS, Stumpo DJ, Kennington EA, Burkholder AB, Ward JM, Fargo DL, Blackshear PJ. Life without TTP: Apparent absence of an important anti-inflammatory protein in birds. American Journal of Physiology – Regulatory, Integrative and Comparative Physiology 2013 DOI: 10.1152/ajpregu.00310.2013