Essentially the same simplified methods were devised for the purification of staphylococcal enterotoxins A, B and C
2. Each of them consisted of only two steps, chromatography on SP-Sephadex C-25 and gel filtration on Sephadex G-75. Each purified enterotoxin was shown as a band by disk electrophoresis at pH 4.3. It formed one precipitin line on agar against homologous anti-enterotoxin serum prepared from rabbits immunized with the purified enterotoxin. Each anti-enterotoxin serum formed one fused precipitin line against crude enterotoxin and reference toxin.
Neither α-hemolysin nor β-hemolysin was detected from purified enterotoxin A, B, or C
2.
The rate of recovery by the purification steps ranged approximately from 73% to 85%.
By SP-Sephadex C-25 chromatography, each enterotoxin was resolved into two or three fractions which were not distinguished immunologically from one another. Heterogeneity of the three enterotoxins was also observed by disk electrophoresis at pH 9.5 and isoelectric focusing in 7.5% polyacrylamide gels with 2% Ampholine, pH 3.5-10.0. From the results of isoelectric focusing in gels, it was recognized that enterotoxin A had at least 5 components with an isoelectric point of approximately 6.5, 6.8, 7.2, 7.7, and 8.3, respectively, enterotoxin B at least 7 components with an isoelectric point of approximately 8.2, 8.5, 8.7, 8.9, 9.0, 9.1, and 9.3, and enterotoxin C
2 at least 4 components with an isoelectric point of approximately 6.2, 6.8, 7.3, and 7.6.
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