FIELD: biotechnology.
SUBSTANCE: method for production of serogroup X Neisseria meningitidis capsular polysaccharide, its conjugate with a carrier protein and an immunogenic composition based on the conjugate for preparation of a vaccine against meningitis. The method is implemented using a fermentation medium comprising casaminoacid, an optimal strategy of nutrient solution addition and an improved process for polysaccharide isolation and purification, exclusive of any chromatographic methods. The polysaccharide and protein ratio in the conjugate is in the range of 0.2 to 0.6. Inventions allow to obtain purified serogroup X Neisseria meningitidis polysaccharide in a yield of 300 to 550 mg/l, average molecular weight of 400 to 550 kDa, yield of 60% to 65% at the purification stage and containing less than 0.5% of protein, less than 0.5% of nucleic acids and less than 5 EU/mg of endotoxins. X polysaccharide is adjusted to a size of 150 to 200 kDa and conjugated to a carrier protein.
EFFECT: increased efficiency.
9 cl, 4 dwg, 11 tbl
