Studies on the Tuberculin Reactivity of Tuberculin-Active Peptide

A comparative study of the tuberculin potency and reactivity to TAP and PPD-S was made in humans and guinea pigs. A comparison of reactions elicited by TAP and PPD-S was made in two groups of guinea pigs previously inoculated with killed bacilli or with living bacilli. The tuberculin reactions produced by TAP and PPD-S in human beings was studied in school children from rural districts. These children were divided randomly into three groups and each group was given a different amount of TAP and PPD-S. The results obtained are as follows: (1) While relative potency of TAP was relatively much weaker than PPD-S in guinea pigs sensitized with tubercle bacilli, in human beings the tuberculin potency of TAP was approximately 1/2 or 1/3 that of PPD-S. (2) There was a marked difference in the tuberculin reactivity to TAP and PPD-S between guinea pigs immunized with killed bacilli and guinea pigs immunized with living bacilli.