Serum Transfer of Delayed Cutaneous Hypersensitivity to Tuberculin in Man

¹ Departments of Medicine, Anatomy and Physiology, Faculty of Medicine and Siriraj Hospital, University of Medical Sciences

A total of 33 freshly discovered tuberculin-negative reactors were injected with the human serum by intradermal route. Twenty-six received serum from ruberculin-positive persons who were suffering from active pulmonary tuberculosis, and seven received serum from a healthy tuberculin-negative person. Seventy-two hours after serum injection, two simultaneous tuberculin tests were again performed on each recipient. Those who received serum from tuberculous patients became converted to tuberculin-positive, and those who received non-sensitive serum remained tuberculin-negative. The failure of tuberculin conversion at the initial test site, performed before serum administration in five of 26 subjects, could be explained in that the tuberculin antigen at the site of the test in such cases had already waned by the time of re-reading the test (six days after injection).

The results of the study thus indicate that there is certain material in the serum of tuberculous patients responsible for the passive transfer of the tuberculin hypersentivity and support the writer's previous works^11,12 and hypothesis¹⁵ that the serum alpha-2 globulin fraction which has been consistently found increased in humans with active tuberculosis could actually be the antibody of the delayed hypersensitivity having been released from the sensitive leukocytes at the time of interaction with specific antigen.