GB911186A - Improvements in or relating to b.c.g. vaccines - Google Patents

Abstract

A process for the production of a freeze-dried B.C.G. vaccine in which B.C.G. organisms (Bacillus of Calmette and Guorin) are cultured in a nutrient medium therefor and thereafter freeze-dried, is characterized in that the said nutrient medium is one substantially free from glycerol, monosaccharides, sugar alcohols and polysaccharides containing a carbonyl group or metabolized by the organisms to a carbonyl-group containing compound. Preferably, the culture is submerged, and the medium contains (a) at least one amino acid and/or an enzymatic digest of casein and/or a meat protein hydrolysate and/or a meat extract to provide essential nitrogen and carbon requirements; (b) a non-hydrolysable non-ionic wetting agent e.g. a polyoxyethylene ether of a phenol or long chain alcohol; (c) nutrient salts i.e. salts of iron, calcium, zinc and copper; (d) a buffer e.g. disodium hydrogen phosphate/potassium dihydrogen phosphate to pH 5.5 to 8.5 and preferably pH 7.0. The culture medium preferably contains L-asparagine as amino acid and may also contain monosodium glutamate and/or L-glutamine. After cultivation for 8-21 days at 35 DEG to 39 DEG C., the organisms are separated from the liquid medium by centrifugation. The organisms are then re-suspended in a freeze-drying medium and freeze-dried. The preferred freeze-drying medium consisting of an aqueous solution of dextran containing a wetting agent and glucose with or without the further addition of monosodium glutamate. Specification 764,718 is referred to.