Discovery of interferon type I, a protein that interferes with viral replication. "While working together at the NIMR, Lindenmann and Isaacs noticed that if they killed viruses using heat and applied the dead viruses to living cells, those cells became resistant to further infections from live viruses.^[2] In 1957, Lindenmann and Isaacs discovered that the cells exposed to the dead viruses secreted a previously unknown substance which blocked future viral infections, which became known as interferon.^[2] It was later found that interferons are too toxic for use as general antiviral drugs, but they are used to treat hepatitis C as well as some types of cancer.^[2] "( Wikipedia article on Jean Lindenmann, accessed 3-2020).