IFNB1 and infection: In accordance with the microarray data, the RT-PCR data showed that CXCL10 (IP-10), IL-6, IL-8, and IFN-β were all expressed at levels that were approximately 100 times higher in the SARS-CoV–infected animals at day 1 than in the uninfected control animals and were still elevated on day 4 after infection.