COMPARISON OF LYMPHOCYTE TRANSFORMATION AND INTRADERMAL REACTIONS TO TUBERCULINS

Abstract

Purified protein derivatives (PPD) of Mycobacterium tuberculosis and other mycobacteria were added to cultures of peripheral blood leukocytes from 21 healthy donors and ambulatory patients. After 4 days of incubation the number of transformed lymphocytes in cultures was determined. Donors then received intradermal tests with 5 TU [tuberculin units] of 4 of the same antigens used in cultures. The pattern of reactivity in the 2 tests was similar in a majority of cases. Two donors had negative reactions in both tests. Cross reactivity was observed regularly in the in vitro test, but it was possible to distinguish previous infection with tubercle bacilli or atypical mycobacteria, or a combined reaction to 2 different microorganisms. Two donors with positive intradermal reactions had negative in vitro reactions, whereas 1 donor had a positive in vitro reaction and a negative intradermal reaction. The lymphocyte culture technique has proved useful for studies on immunity. The results suggest that the method may also be employed as a research tool for detecting previous exposure to mycobacteria.