Antigenic and immunogenic characteristics of subcellular fractions and whole cells of a rough E. coli 0111 (J5) mutant.

Little information is available on the antigenic and immunogenic properties of an E. coli rough mutant: J5 derived from E. coli 0111:B4, and the relationship of J5 to other cross-reacting antigens of Enterobacteriaceae. Subcellular fractions of J5 and various antigen preparations were tested against antisera to Enterobacterial Common Antigen (ECA-Kunin) and to the Re mutant of S. minnesota (R595). ECA-Kunin was demonstrated in all subcellular fractions of the J5 mutant by means of indirect hemagglutination and by hemagglutination inhibition tests. This common antigen was separable from J5 LPS by ethanol fractionation and by phenol-chloroform-petroleum ether extraction. Treatment with alkali destroyed the hemagglutinating reactivity of ECA-Kunin and revealed the complex nature of J5 surface antigens; an alkalinized 20p30 fraction (containing cell wall components) contained both specific J5 antigen and an antigen which cross-reacted with S. minnesota and S. typhimurium. This antigen was shown by absorption studies to be a new common antigen other than Re LPS or ECA-Kunin. Studies of J5 LPS by ELISA demonstrated that there was a shared cross-reactive immunodeterminant between the glycolipids of J5 and Re. Accordingly, heat-killed J5 preparations were complex vaccines which were able to elicit an antibody response with at least two specificities: ECA-Kunin and the specific J5 antigen.