Production of polysaccharides
Mr. Sridhar, Chief Scientist – Fermentation
Mr. Sridhar says that Nm Vac-4DT is a next-generation JN vaccine that will cover 4 different meningococcal Neisseria meningitidis serogroups collected by Scientific Director Jeeri R. Reddy, PhD, from Africa, Americas, Europe and Asia during 1990 through 1995. Among other complex production processes, the carrier protein that gives Nm Vac-4 DT some of its special characteristics is grown at our Omaha manufacturing facility, where the key focus is quality control, increased productivity and efficiency. The protein DT is isolated from the Corynebacterium diphtheriae bacterium, grown in large quantities, then separated from the bacterium and puriﬁed. “We’re expressing components of bacteria, then performing biochemical rearrangements or restructuring to actually make the vaccine work.”
Carrier Protein conjugation to polysaccharide Is the Key.
Dr. Seshu Gudlavalleti, Chief Conjugate Scientist.
Characterization and control of critical process steps in conjugate vaccine production Polysaccharide Activation. This involves, Degree of activation (colorimetric assays) Molecular size (SEC-MALLS), Critical substituent groups, e.g. o-acetyl or pyruvyl (NMR, colorimetric assays), Polysaccharide-Protein Conjugate, Saccharide:protein ratio (colorimetric assays), Free sugar (physical separation and colorimetric assays) Free protein and polysaccharides (SEC-HPLC), Molecular size distribution (size exclusion chromatography), Freedom from conjugate chemicals (colorimetric assays), Protein modification (amino acid analysis)