158 BACTERIOPHAGES 



phages T2, T3, T4, T6, and T7. The difference between this 

 antigen and that described above which inactivated only T3, T4, 

 and T7 was traced to the use of pyridine in the extraction proce- 

 dure. Incubation in 50 per cent pyridine at 37 ° C resulted in a 

 rapid destruction of the T2 and T6 neutralizing activity of the 

 purified antigen without affecting its activity against T3, T4, 

 and T7. The purified antigen was an electrophoretically homo- 

 geneous complex of protein, lipid, and polysaccharide. 



Digestion with pancreatin resulted in removal of most of the 

 protein, with a concomitant increase in serological activity and 

 in phage-neutralizing activity. Extraction with phenol, which 

 removed all detectable protein, resulted in loss of T2 and T6 

 activity. This lipocarbohydrate contained glucose, galactose, 

 glucosamine, and heptose. Its composition was 45 per cent re- 

 ducing sugars, 29 per cent lipids, 4 per cent acetyl, 4 per cent 

 phosphorus, and 1 3 per cent ash. 



In an extension of this work, Goebel and Jesaitis (1953) studied 

 the properties of a somatic antigen isolated from a phage-resist- 

 ant variant of phase II Sh. sonnei, designated as 11/3,4,7, sus- 

 ceptible only to T2 and T6. The somatic antigen was isolated 

 from strain 11/3,4,7 and its chemical, serological, and antiviral 

 properties were examined. The purified lipocarbohydrate 

 protein antigen inhibited T2 but had no inhibiting effect on T3, 

 T4, T7, or T6. The purified antigen was digested with pan- 

 creatin to remove much of the protein. This degraded antigen 

 was much more active against T2 but still was without effect on 

 the remaining T phages. The variant antigen is serologically 

 distinct from the parent phase II antigen, but is related to it. 

 The enzymatically degraded antigen of the variant differs from 

 the corresponding antigen of the parent in electrophoretic 

 mobility, optical activity, and chemical composition. The 

 lipocarbohydrate was separated from the protein by treatment 

 of the degraded antigen with phenol. Paper chromatography 

 of the hydrolyzed lipocarbohydrate revealed only one saccharide, 

 an amino sugar which was neither glucosamine nor chondrosa- 

 mine. In the case of phase II Sh. sonnei, mutation to phage re- 



