IFNB1 and infection: In further support of such a model it has been shown that macrophages infected in vitro with LASV also support virus replication, but without activation or induction of cytokine responses, while infection with the closely related but apparently human apathogenic Mopeia virus results in up-regulation of mRNAs encoding IFN-α, IFN-β, TNF α and IL-6 [29], [30], [43].