2023-10-10 17:01:00
Genetically Modified Chickens Show Resistance to Bird Flu, but Concerns Remain
A research team from the University of Edinburgh has successfully created genetically modified chickens that are largely resistant to bird flu. By exchanging a gene in the animals’ germ cells, the researchers were able to produce birds that barely responded to normal doses of the bird flu pathogen.
According to the team led by Alewo Idoko-Akoh and Mike McGrew, the genetically modified chickens showed no significant differences from other chickens during the two-year study period, except for their resistance to bird flu. However, they were not resistant to extremely high doses of the pathogen, which the team considers a potential risk of their genetic engineering technique.
Bird flu, caused by various viruses of the Influenza A type, poses a constant threat not only to birds but also to humans. It has the potential to cause a pandemic, as stated by the authors of the research. The H5N1 influenza virus variants are currently causing unprecedented bird deaths in Europe, Asia, Africa, and America. The virus has also been responsible for deaths in mammals and, in isolated cases, in humans. Vaccinations of poultry have proven unreliable protection against the mutation-prone bird flu viruses.
In an attempt to find a different approach to combating the virus, the research team focused on the ANP32 family of proteins, which influenza viruses utilize to multiply in body cells. Using the Crispr-Cas9 gene editing tool, they created chickens with a modified gene for the ANP32A protein, which is also found in a modified form in mammals.
The team tested the chickens’ immunity using the H9N2 influenza virus, which is less aggressive than the H5N1 strain and prevalent in East Asia. The genetically modified chickens showed little to no infection when exposed to normal doses of the pathogen. However, when exposed to an extremely high dose that was 1,000-fold greater, five out of ten chickens became infected. These infected animals did not develop a high viral load and did not transmit the virus to other animals. However, further analysis revealed that the virus used less suitable protein variants, ANP32B and ANP32E, to multiply in the infected birds instead of ANP32A.
What is particularly concerning is that these pathogen variants were able to multiply in human respiratory tract cells in the laboratory, using the slightly modified ANP32A and ANP32B proteins found in humans. The researchers describe this adaptation to mammals as unexpected, highlighting the need for complete resistance to different avian flu genotypes. Merely changing the gene for ANP32A alone does not provide sufficient resistance.
In an upcoming study, the researchers plan to create chicken cells lacking all three ANP32 proteins (ANP32A, ANP32B, and ANP32E). Although the virus was unable to multiply in these cells in the laboratory, the team believes that disabling all three proteins may affect the fitness of the chickens.
While the development of genetically modified chickens with resistance to bird flu is an exciting breakthrough, concerns remain about the virus’s ability to adapt and infect humans. Further research and experimentation are necessary to understand the full implications and potential risks of this genetic engineering approach.
– RND/dpa]
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