Stimulated production of interferon by a low-molecular-weight factor from chicken-egg fluids.

Exposure of five-year-old L-929 cell monolayers to low-molecular-weight factor obtaiend from chicken egg-yolk fluids stimulated the production of Semliki Forest virus (SFV)-induced interferon, particularly when the cells were infected with a low-input multiplicity of SFV. The stimulatory effect on interferon production was not expressed in polyriboinosinic acid:polycytidylic acid-induced interferon. Furthermore, the high yield of interferon was correlated with and followed the increase in viral yield, thus suggesting that the yolk factor stimulates the growth of SFV, which in turn triggers the higher production of interferon. The outstanding feature of the yolk factor is its ability to stimulate the production of virus-induced interferon during the lytic cycle of virus replication.