Antiviral Activity of Silkworm Expressed Recombinant Human Macrophage Colony-Stimulating Factor in Vitro and Its Mechanism

Cells, pretreated with the recombinant human macrophage colony-stimulating factor (rhM-CSF) expressed in silkworm larvae, were inoculated with several viruses to observe the effect of rhM-CSF on viral replication. The results showed that in cultures of fibroblast derived from human fetal skin-muslce tissues infected with the viruses (including VSV, rhinovirus, influenza virus type A3, HSV-1, HSV-2, adenovirus type 6 and type 11), rhM-CSF inhibited the virus-induced cytopathy, which defered or relieved the cytophathy and that in the cells derived from breast feeding rabbit kidney infected with HSV-1, rhM-CSF reduced titer of the virus in a rhM-CSF dose-dependent pattern,in which rhM-CSF with the dose of 1×106 U/L made the viral titer drop dwon over 200 times. This antiviral activity of rhM-CSF could be partially neutralized by anti-IFN-βMcAb, but not by antiTNF-α, anti-IFN-α, or anti-IFA-γ McAb, indicating the mechanism of the antiviral activity of MCSF is related to the induction of IFN-β.