Isolation and characterization of the K1 (L) antigen of Escherichia coli.

Bolaños, Roger (Tulane University, New Orleans, La.), and Charles W. DeWitt. Isolation and characterization of the K1 (L) antigen of Escherichia coli. J. Bacteriol. 91:987-996. 1966.-An acidic polysaccharide with the serological properties of the K1 (L) antigen has been isolated from Escherichia coli O2:K1:H4 by means of phenol-water extraction, fractionation with hexadecyltrimethylammonium bromide (Cetavlon), filtration through Sephadex G-200, and chromatography on anion-exchange cellulose columns. Nucleic acid and protein content were reduced to a nondetectable level. There is no contamination with O antigen. The active material appears in two different positions in the Cetavlon fractionation, each with a slightly different serological specificity, as followed by the inhibition of passive hemagglutination. By paper chromatography, the polysaccharide moiety of the O antigenic fraction is composed of glucose, galactose, hexosamine and rhamnose. The absence of colanic acid in either K1 fraction was not proven, although its participation in our assay system, as well as the participation of the common or cross-reacting antigen, was ruled out by serological means.