A dialysable fraction from tuberculin-sensitive human white blood cells capable of inducing tuberculin-delayed hypersensitivity in nagative recipients.

Peripheral white blood cells were obtained from tuberculin-hypersensitive donors. These cells were disrupted and the supernatants dialysed. The dialysable and non-dialysable portions were each capable of transferring tuberculin-delayed hypersensitivity to negative human recipients. If the dialysable fraction was lyophilized and taken up in 0.33 volumes of water compared to the original cell volume a heavy precipitate formed. The supernatant was still capable of transferring delayed hypersensitivity. This capacity was not removed during equilibrium dialysis with BCG antiserum. The dialysable fraction was found to contain pentose (but not deoxyribose), hexose, lipid phosphorus and other substances not yet identified. By immunoelectrophoresis only one to two precipitin bands formed between the dialysable fraction and rabbit anti-human white blood cell antiserum. There was also a thirty-fold decrease in protein N of the dialysate fraction compared to the total disrupted white blood cell supernatant.