TNF and infection: Twenty-four hours post infection, enhanced viral genome replication was observed in cells overexpressing M. This enhancement was probably caused by the M-mediated inhibition of the cellular antiviral response since the RLR-mediated antiviral innate immune response is well known to be essential for the inhibition of viral replication at the early stage of infection.2,10–12 We next performed ELISA experiments and found that the secretion of IFN-β and TNF-α following SeV infection or poly (I:C) transfection was also impaired in HEK293-M cells (Fig. 1G).