Interferon Responses Could Explain Susceptibility to Severe COVID-19
Impaired or delayed antiviral signaling could be a treatable cause of serious COVID-19.
What are interferons?
Interferons are proteins made by cells in response to infection. In humans, there are 3 categories of interferons: type I, type II, and type III. Insufficient or inappropriately timed activation of interferon signaling may contribute to severe cases of COVID-19, which is caused by the coronavirus SARS-CoV-2. Too little interferons at the beginning and too much later in the infection could contribute to severe or even lethal cases.
In humans, type I interferons consist of IFN-α, β, ε, κ, and ω. Type I interferons are mostly produced by infected cells and cells of the immune system. There is a single member of the type II interferon family: IFN-γ. Type II interferon is also produced by immune cells. Type III interferons consist of 4 subtypes of IFN-λ. Although some immune cells produce type III interferons, these are also produced by epithelial cells or cells that are from the same developmental path as epithelial cells.
Epithelial cells are the cells that line the parts of the body that come into contact with the outside world: the respiratory tract, the gastrointestinal tract, and the…
