SOCS1 and infection: YF-17D also down-regulated SOCS1 mRNA level in HeLa cells in both the early (12 hpi) and late phases (24–48 hpi) of infection, and in the early phase of infection in HEK293T cells, but SOCS1 mRNA level increased by four-fold in the later phase of infection (48 hpi), as shown in Figure 3B.