Science and Technology Daily, Kunming, March 14 (Reporter Zhao Hanbin) A team led by Lai Ren, a researcher at the Kunming Institute of Zoology, Chinese Academy of Sciences, recently discovered a polypeptide toxin with immunosuppressive function from the salivary glands of bats.
This immunosuppressive toxin exerts an immunosuppressive function by inhibiting the activity of leukotriene A4 hydrolase, forming an immunosuppressive microenvironment locally in the host, and at the same time promoting virus transmission.
This important study was published in the Proceedings of the National Academy of Sciences.
Bats are considered potential hosts for many microorganisms, especially their mouths are considered to be a repository of microorganisms, some of which can infect other animals and humans and cause zoonotic diseases.
More and more studies believe that the reason why the virus stays in bats is due to the immune tolerance mechanism of bats.
The oral cavity as a channel for virus entry and spillover implies that the oral cavity of bats may be a site of immune tolerance, and the oral host factors that make bats immune-tolerant may promote microbial residency and spread.
Lai Ren's research group and the team of Professor Deng Guohong of Army Medical University recently discovered an immunosuppressive polypeptide toxin MTX from the salivary glands of the big-footed bat, which inhibits leukotriene A4 hydrolase, trypsin, plasmin and elasticity. Protease function, and the bifunctional metalloenzyme with anti-inflammatory and pro-inflammatory effects, leukotriene A4 hydrolase, is especially important for the immune regulation of the body.
In the activity detection experiment, it was found that the toxin only inhibited the production of leukotriene B4, the pro-inflammatory product of leukotriene A4 hydrolase, showing its unique inflammation-inhibiting characteristics.
This means that the immunosuppressive toxin is one of the important factors for the local formation of a balanced microenvironment of immune tolerance and immune defense in bats, allowing the virus to reside for a long time.
In addition, studies have shown that MTX-administered cells and mice are more susceptible to influenza A virus infection. The decrease is related to the fact that the intensification of infection eventually leads to more severe cell and tissue damage, further showing the pro-viral infection effect of its immunosuppressive mechanism, providing the possibility for the horizontal spread of the virus.
The first discovery of this bat natural host immunosuppressive protein provides a good candidate drug template for the future development of safe and efficient anti-immune storm drugs.