Hyporesponsiveness to Dog Interferon Induction in vitro

Sera from dogs that were hyporesponsive to interferon ( IFN) induction blocked virus induction of I FN in spleen cells in vitro but not I FN action in dog kidney cells. Similarly, macrophages or their culture fluids were found to block IFN induction in lymphoid cells in vitro. Lymphoid cells deprived of phagocytic ells secreted IFN continuously for 4 days, whereas lymphoid cells in the presence of phagocytic ells produced IFN for only 1 day. It was speculated that the 'hyporeactivity factor ' in the sera from hyporesponsive dogs was macrophage-derived