Anti-plague vaccine prepd. from Yersinia pestis, EV strain - by extn. of cellular membrane antigen, purification and fractionation

摘要

Prodn. of an antiplaque (bubonic plague) biochemical vaccine from Yersinia pestis, strain EV, comprises a) fermentation of Yersinia pestis, strain EV, in liq. medium at a pH slightly above neutral, under medium aerobiosis, at 29-31 deg.C and for a period depending on the inoculum; (b) Low speed centrifugation, lysis of the bacterial culot, then higher speed centrifugation of the lysate and sepn. of the culot of cellular membranes; (c) extn. of the vaccinating membrane antigens by contacting the cellular membrane culot with an aq. soln. of sodium chloride (few% concn. pref. 2-3%), under continuous shaking, at refrigerated temps. (pref. 0-4 deg.C) and pH 7.5-8.5 (pref. 8.0) for at least 60 hrs. (pref. about 70 hrs); (d) Low speed centrifugation and decantation of the membrane extract, followed by purificn. of the supernatant extract by ultrafiltration, using a filter membrane to give the desired Mol. Wt. cut and (e) Dialysis of the lowest Mol. Wt. fractions and lyophilisation of vaccinating antigenic fractions (pref. those of Mol. Wt. above 300,000). The process produces a vaccine free from the secondary reactions of the killed vaccine and more stable and consistent than that of the Gerard and Robic living vaccine.