The role of human spleen interferon on natural killer activity of peripheral blood lymphocytes enriched in large granular lymphocytes

The elimination of monocytes as well as B- and T-lymphocytes by forming rosettes with high affinity for sheep red blood cells yielded an enriched population of both natural killer (NK) activity (cytotoxicity: 65.4 +/- 9.9% with an E/T ratio of 12:1, P less than 0.005) and large granular lymphocytes (LGL: 76 +/- 13%) compared to the untreated lymphocyte population where NK activity is 35.7 +/- 17.3% (E/T 12:1) and the percentage of LGL of 26 +/- 6%. We studied the action of type I interferon (IFN) obtained from human spleens, on NK activity of 9 peripheral blood lymphocyte populations and 9 enriched in LGL. NK activity of the total lymphocyte population is significantly increased (P less than or equal to 0.05) in 6 out of 9 cases after treatment by interferon. Cell populations enriched in LGL showed increased NK activity in only one case after treatment by interferon, but no increased activity was found in the other cases. These results are compatible with the notion of cellular cooperation in increased NK activity by interferon.