The virulence-enhancing factor of mucins. 2. Fractionation studies on hog gastric mucin

1.A biological technique has been established for the assay ofthe virulence-enhancing factor ofmucins and chemical fractions thereof.2. Unknown mucin samples are compared with a ' standard' mucin preparation.A constant number of Bacterium typhosum (strain Ty2) is in- jected intraperitoneally into batches of twenty mice in the presence of falling concentrations of the test materials.Comparisons of death rates and concen- trations are made by probit analysis.3. The assay can detect twofold differences in virulence-enhancing activity with probability P= 095.4. The toxicity of mucin preparations at high concentrations is noted.It is a pleasure to record my gratitude to Dr D. W. Henderson for his helpful advice.I am indebted to Miss J.