Transfer in vitro of tubercolin hypersensitivity by sensitised lymphocytes

An account is given of the experimental in vitro transfer of PPD-specific delayed hypersensitivity to peripheral leukocytes pulsed with a very small portion of autologous lymphocytes pre-sensitised with PPD-specific transfer factor (TF). Transfer was assessed by means of the leukocyte migration inhibition test, the lymphocyte locomotion test, and the leukocyte adherence inhibition test. These tests were positivized in all the experiments. It is suggested that these results indicate that TF does not act in itself, but triggers a reaction that expands the effect of hypersensitivity.