Skin reaction, inhibition of macrophage migration, and lymphocyte transformation with tuberculin active peptide (TAP) and arabinogalactan obtained from tubercle bacilli.

Arabinogalactan purified from heat-killed tubercle bacilli failed to elicit a delayed type of skin reaction and had no ability to induce in vitro lymphocyte blast formation in sensitized guinea pigs. It was, however, inhibitory to migration of bronchoalveolar washing cells by the indirect test, but not by the direct test, and capable of eliciting an immediate type of skin reaction and anaphylaxis when injected into sensitized guinea pigs. Tuberculin active peptide (TAP) was active in all of in vitro and in vivo cell-mediated immune responses, but not in immediate responses.