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Supplementary Note on Ultrafiltration in the Preparation of Pneumococcal Polysaccharides

Division of Laboratories and Research, New York State Department of Health, Albany

Abstract

The isolation of pneumococcal polysaccharides by ultrafiltration (1) is greatly facilitated if a peptone-dialysate or ultrafiltrate is used in the medium. The procedure is similar in principle to that used in other studies of the purification of diphtheria toxin (2). The details of the preparation are outlined as follows:

Eleven hundred sixty grams of peptone (Parke, Davis and Company) suspended in tap water to a total of 4.5 kgm. are divided between two bags of cellophane¹ and held for seven hours at 90°C. in a bath of 24.5 kgm. of tap water. To the dialysate are added an equivalent amount of tap water, 0.1 per cent potassium hydrogen phosphate, 0.1 per cent potassium dihydrogen phosphate, and 0.5 per cent sodium chloride; the broth is then adjusted to pH 7.8. For further refinement the sterile peptone dialysate is subjected to ultrafiltration through a 4.7 per cent nitrocellulose-coated thimble² and the filtrate used for culture medium as described above for the original dialysate.

Footnotes

¹ E. I. Du Pont de Nemours and Company, "Cel-O-Seal" Division; transparent seamless tubing, 4.5-inch diameter, 0.0035-inch wall thickness.

² A less porous membrane has not been tried, but it might prove advantageous.