Antibodies to the truncated (short) form of 'O' polysaccharides (TFOP) of Vibrio cholerae O139 lipopolysaccharides protect mice against experimental cholera induced by encapsulated O139 strains and such protection is mediated by inhibition of intestinal colonization of vibrios

An antiserum raised against the lipopolysaccharides (LPS) of an encapsulate d Vibrio cholerae O139 strain was shown to induce passive protection agains t challenge with O139, but not O1? organisms. Subsequent experiments, howev er, revealed that the purified LPS, obtained by the conventional phenol-wat er extraction method, contained capsular polysaccharide (CPS) material. The refore, another antiserum was raised by immunization with electrophoresed g el-cut material containing only the truncated (short) form of 'O' polysacch arides (TFOP) linked to the core of O139 LPS. Anti-TFOP antibodies and thei r Fab (lgG) fragments induced passive protection against challenge with col onial variants of encapsulated O139 strains and such protection was mediate d by inhibition of intestinal colonization. These results suggest that it i s possible to engender protection against encapsulated O139 strains by usin g TFOP material (devoid of CPS) as the immunogen. (C) 1999 Published by Els evier Science Ltd. All rights reserved.