The authors used two rat coronaviruses on alveolar epithelial cells taken from 6-8 weeks old rats. Infection with the viruses caused the increase in expressed of both IL-1a and IL-1b. The authors concluded that the virus-induced chemokine expression was subsequently reduced by the IL-1 receptor antagonist, suggesting that IL-1 produced by infected cells induces uninfected cells to express chemokines. This evidence concerns the gene IL1B and infection.