The type I interferon system and viruses

Published on July 31, 2018   36 min

A selection of talks on Infectious Diseases

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Hello, my name is Adolfo Garcia-Sastre, Professor at the Department of Microbiology at Icahn School of Medicine at Mount Sinai in New York. I have be working now for more than 20 years on virus-host interactions; especially interactions with the type one interferon system; and I will be giving you a lecture on the type one interferon system and viruses.
Interferon is actually the oldest known cytokine. It was discovered, a while ago in 1957 by Isaacs and Lindenmann, who found that interferon was a cellular factor with antiviral activity, secreted when they treat sickle cells with partially heat-inactivated influenza viruses. When they moved the supernatum from these chicken cells, in to new chicken cells, they found that these new chicken cells become resistant to viral infection - and that was due to the activity of interferon. Now today we know that there are more than one type of interferon, type one interferon alpha-beta (α/β) is one of the interferons and this is produced by most cells. It is the one that is most studied, has direct antiviral activity with a spectrum of antiviral activity and is secreted in response to pathogens like viruses. We also have type two interferon or interferon gamma (IFN-γ). It also has antiviral activity, but the main action of interferon gamma, which is produced by B cells and NK cells, in response to IL-12 (Interleukin -12) is to modulate adaptive immune responses to viruses. Then finally we have type III interferons or interferon lambdas (IFN-λs), which are very similar to type I interferons in terms of how they act and how they have been induced, but the expression of its receptor is restricted to specific cell types. So not all the cells are able to respond to type III interferon, it's mainly epithelial cells - which are able to respond to type III interferon, while almost any cell in an organism has the ability to respond to type I interferon.