Sonic Extraction of Labile Bacterial Constituents

Recent investigations have indicated that the killing of certain bacteria by available agents destroys or alters at least some of their antigenic constituents. Thus the investigations of Felix 1 have revealed a labile virulence (Vi) antigen detected only in living, virulent strains of Eb. typhi. Similarly, Mudd, Pettit, Lackman and Czarnetzky 2 have found that the antibody responsible for the phagocytosis of a strain of Streptococcus hemolyticus is elicited in rabbits by the injection of living organisms and that the living organisms will absorb the antibody from immune serum so produced. The corresponding bacterial antigen itself has resisted all ordinary methods of separation or fractionation.

Since it has been shown that sonically killed bacteria are disintegrated 3 , 4 , 5 and since some heat labile proteins are not denatured by the sonic treatment, 6 it appeared possible that labile but important antigens such as those referred to above might be extracted by an adaptation of the method of sonic disintegration. The purpose of this paper is to describe the apparatus and technique which we have used; to make brief mention of the antigens obtained thus far; and to point out some implications of these observations.

We have used a modified Pierce magnetostriction oscillator as the source of intense vibrations of about 8900 c.p.s. A similar oscillator has been described by Gaines 7 and was used by Chambers and Gaines 3 in their earlier work. The circuit design in our apparatus differs somewhat from that of Gaines but the essential features of the sound source are the same. The electrical circuit we have used is shown in Fig. 1.

The arrangement of the vibrating element with relation to polarizing and driving coils is illustrated in Fig. 2. The vibrator itself is a tube of No. 20 Stubbs gauge, seamless, cold-drawn nickel tubing 24.6 cm. in length and 1.875 cm. in outside diameter. The upper end of the tube is closed by a welded nickel cap as in the original Gaines device, but we have found it unnecessary to slit the lower half of the tube. Adequate radiation of heat due to eddy currents is possible, as described below, when no such kerf is present.