| 摘要 |
Avirulent strains of Brucella abortus are cultivated in a nutrient medium containing an adequate carbon source which is fructose, or contains at least 0.1% w/v. fructose in respect of the medium, or at least 2.5% w/w. fructose in proportion to the total carbon source, the culture then being freeze dried to give a living vaccine of the micro-organism. The preferred strain of organism is S.19; the medium is of conventional constitution regarding components other than fructose, the latter suitably being present in about 4% w/v. concentration. Alternatively, the carbon source may be, e.g. about 4% w/v. of a 3:1 by weight mixture of glucose with fructose. Preferably sucrose, about 5% w/v. is added to the culture before freeze drying, as as a stabilizer. Cultivation in the presence of fructose is said to increase the number of viable organisms in the freeze-dried product, and to improve its stability on storage.ALSO:Living Brucella abortus vaccines are prepared by cultivating a non-virulent strain thereof in a nutrient medium, having an adequate carbon source which is fructose or contains at least 0.1% w/v. fructose in respect of the medium, or at least 2.5% w/w. fructose in proportion to the total carbon source, and freeze-drying the resulting culture. The preferred strain is the S.19 strain. A suitable additional carbon source is glucose. Before freeze-drying, sucrose is preferably added to the culture, to about 5% w/v. concentration, to improve the stability of the vaccine. The presence of fructose as a carbon source is said to increase the number of viable organisms in the vaccine after freeze-drying, and to improve its storage stability. |
