Further Observations on the Precipitable Substances of B. typhosus and B. paratyphosus B.

Abstract

In preceding notes 1 two different precipitable substances derived from B. typhosus were mentioned which, according to the high N content and digestibility by trypsin seemed to be of protein nature and different from the trypsin resistant antigen of Douglas and Fleming. When a solution prepared according to the directions of these authors was precipitated with alcohol, first in alkaline, then in acid solution, a product was obtained almost biuret free and yielding much reducing sugar on hydrolysis. A substance with similar properties was prepared as follows: Typhoid bacilli were extracted with N/2 NaOH for 1 ½ hours at 37°, the solution adjusted to slight alkalinity, centrifuged and the supernatant fluid precipitated with alcohol. The precipitation with alcohol was repeated once in alkaline and once in acid solution removing each time some insoluble material. A further precipitation was made with barium hydroxide solution. The substance gave faint or negative protein reactions and yielded about 40 per cent reducing sugar (calculated as glucose) after heating for 5 hours with N/2 HCl. It reacted intensely with common immune sera for B. typhosus and for B. enteridis Gärtner, and with sera prepared with the antigen of Douglas and Fleming, slightly, if at all, with an immune serum for B. paratyphosus B. Negative or very feeble reactions were obtained with immune sera for the two preparations from B. typhosus mentioned above.

A typhoid immune serum absorbed with alcohol treated bacilli, still containing the so-called large flaking agglutinins (Weil and Felix) was without action on any of the absove three preparations. It would seem, therefore, that they all may be different from the labile agglutinogen, supposed to be connected with the agglutination of the flagelli (Smith and Reagh, 2 Beyer and Reagh 3 ).