Activity of normal killer cells and their sensitivity to interferon in old mice

The authors studied the activity of natural killers in young and old mice and effects on this activity of interferon and its inducer (synthetic polynucleotide poly-I:C). The activity of natural killers as indicated by the 51Cr-release microtest and the content of the cells that recognize and lyse the target cells, determined in isolated conjugates in agarose were appreciably lower in old mice than in young ones. Administration of poly-I:C or interferon to the animals (or interferon treatment of splenocytes in vitro) led to an increase in the activity of natural killers in young mice, with no significant effect on old animals' cells.