Non-Specific Activation of the Alcohol Soluble Antigen of Tubercle Bacillus.

Abstract

In a previous publication 1 it was found that the addition of commercial lecithin and alcoholic heart extract increased the potency of an alcohol extract of the tubercle bacillus as an antigen in the complement fixation reaction about ten times. The potency of certain preparations derived from the alcohol extract was increased about 100 to 200 times. Further work on this subject, although it is not yet completed, revealed the following characteristics.

An alcohol or ether extract of the tubercle bacillus and the preparations representing different stages of the purification of them, as described in our first paper 2 are activated with the addition of lecithin only if they are mixed with the lecithin in alcoholic solution and diluted together. The addition of saline suspension of lecithin to the saline suspension of the specific substance has no activating effect. Contrary to this, the preparations described later in these PROCEEDINGS 3 are activated whether the lecithin is added to the alcohol or to the saline solution of the preparations. The different behavior of the two classes of preparations toward lecithin is due, probably, to the circumstance that the substances later mentioned contain the specific substance nearly or entirely separated from the lipoids and are water soluble. In the experiments described in the first publication we examined in saline solution only the substances belonging to the second group showing strong activation, and we did not observe that the others are not activated in saline suspension.

With the bacterial substances of the first class, which are activated only if mixed in alcohol solution with lecithin further work was done in two directions. The effect of an increasing amount of lecithin was studied, and a marked optimum was found.