Conditioned enhancement of natural killer cell activity, but not interferon, with camphor or saccharin-LiCl conditioned stimulus.

Pavlovian conditioning of the natural killer (NK) cell response has been demonstrated by pairing camphor with polyinosinic:polycytidylic acid (poly I:C) in nine association trials. The NK cell response could be conditioned also by using combined saccharin and lithium chloride (LiCl) as the conditioned stimulus. The camphor and saccharin-LiCl paradigms were tested to determine if the conditioned NK cell activity was the result of conditioning of the interferon response. Interferon levels were measured at 6 hr and NK cell activity at 24 hr after application of the conditioned stimulus. The interferon levels measured in separate experiments were not uniformly elevated in conditioned animals compared with controls.