The virulence-enhancing factor of mucins. 5. The different components of the ‘third factor’ involved in virulence enhancement

Abstract
The virulence-enhancing activity of the 3 factor of hog gastric mucin resides in at least 2 predominantly polysaccharide fractions which differ in chemical nature and in some biological properties. The first, which has been purified and identified (see following paper), contains highly ionic sulfate residues and has an intense anticoagulatory and anticomplementary activity; the 2d fraction, which is still impure, is devoid of such residues and activities. When combined together in the biological assay for the 3d factor, the 2 fractions have a synergistic effect. Various bacterial polysaccharides have virulence-enhancing activities and other biological properties similar to the 2d of these fractions.