[Isolation of staphylococcal enterotoxin type B and a study of its physicochemical, biological and immunological...

The homogeneous preparation of type B staphylococcal enterotoxin (SEB) has been obtained by its adsorption from the culture fluid on amberlite, elution, isoelectric focusing in the ampholine system and gel filtration in a column packed with Sephadex G-25. The isolated SEB component is a thermostable protein, homogeneous in its antigenic composition and according to the results of disc electrophoresis in acrylamide gel. Its molecular weight is 28,000 daltons with pI equal to 8.6 (the main component), 8.0 and 8.25 (the minor components). All the forms are immunochemically identical. The minimum enterotoxic dose of SEB for cats is 3-5 micrograms per kg of body weight. The biological activity of the enterotoxin disappears under the action of 6 M urine. Monospecific antiserum to SEB with a precipitating antibody titer of 1:64 has been obtained.