This study demonstrates the capacity of HM-γ-
PGA treatment to significantly protect murine macrophage cells (RAW 264.7 cells) against NDV
infection. Such protection can be explained by the induction of
antiviral state of HM-γ-
PGA in RAW 264.7 cells via TLR4-mediated IRF-3, IRF-7, IFN-β, and IFN-related gene induction as shown in time-dependent changes in
mRNA expression confirmed by polymerase chain reaction (PCR). Moreover, the present research also showed that HM-γ-
PGA can induce proinflammatory
cytokine secretion in RAW 264.7 as measured by
enzyme-linked
immunosorbent assay (ELISA). Therefore, our findings suggest that HM-γ-
PGA can be a potential
antiviral substance that can inhibit NDV
infection through its stimulation of
antiviral state on RAW 264.7 cells. These results have been consistent with the previous studies showing that HM-γ-
PGA can protect RAW 264.7 cells and mice against
influenza infection. However, it should be noted that although murine macrophage cells are susceptible to NDV, they are not the natural host cells of the virus; thus further in vivo and in vitro studies involving chicken and chicken immune cells are needed to fully assess the efficacy and applicability of HM-γ-
PGA in the poultry industry.