Mutual Linkage Between the Components IX and XII in Salmonella Typhi O-Antigen

Abstract

An investigation was made into the serologic activity of the lipopolysaccharide from the typhoid 0901 strain, purified by the method described by Webster (7). In the agar gel precipitation test (double diffusion technique) this antigen was shown to contain at least two components. After treatment with 0.02 N NaOH one of the lines did not appear. Moreover, the shape of the precipitation curve of NaOH-treated lipopolysaccharide was changed in such a way as to indicate the neutralization of a maximum amount of antibody. Probably the NaOH treatment destroys a protein antigen. Supernatant and precipitate analysis in the quantitative precipitation test revealed that the antigens of the White-Kauffmann scheme (IX and XII) are always precipitated together, even by an absorbed serum that contains only the anti-IX factor and by a paratyphoid A serum (anti-II, anti-XII). From this it was concluded that the two antigen components are very closely bound together, possibly in one molecule.