Evaluation of GC-MS for identification and characterization of pneumococcal serotype 24A, 24B, and 24F capsular polysaccharide.

Analysis of pneumococcal polysaccharides (PnPs) has been an arduous task, especially in similar serotypes. Pneumococci invades the host immune response by modulating capsule structure with small genetic changes making them indistinguishable from similar serotypes by conventional modes of analysis. The new serotype 24F causing invasive pneumococcal-resistant infection is an analytical challenge for its analysis as related serotypes 24A and 24B Ps share a common backbone. The difference in the branched chain which contains arabinitol and ribitol in 24F and 24B respectively are stereoisomers making their identification even more challenging. The composition analysis by GC-MS revealed distinct peaks for arabinitol in 24F and 24A Ps and ribitol in Pn 24B serotype polysaccharide. The mass spectral analysis confirmed their identification along with a heterologous cross-reactivity which confirmed anti-Pn-24F mAb reactive to Pn 24B than Pn 24A. The quantitative analysis of pneumococcal 24A, 24B and 24F using GC-MS showed sensitive analysis over the concentration range 3.125-200 µg/mL with regression coefficient >0.99 making ideal modality for the characterization, identification, and quantitation of pneumococcal 24A, 24B and 24F similar serotypes.

Evaluation of Critical Quality Attributes of a Pentavalent (A, C, Y, W, X) Meningococcal Conjugate Vaccine for Global Use.

Towards achieving the goal of eliminating epidemic outbreaks of meningococcal disease in the African meningitis belt, a pentavalent glycoconjugate vaccine (NmCV-5) has been developed to protect against Neisseria meningitidis serogroups A, C, Y, W and X. MenA and X polysaccharides are conjugated to tetanus toxoid (TT) while MenC, Y and W polysaccharides are conjugated to recombinant cross reactive material 197 (rCRM197), a non-toxic genetic variant of diphtheria toxin. This study describes quality control testing performed by the manufacturer, Serum Institute of India Private Limited (SIIPL), and the independent control laboratory of the U.K. (NIBSC) on seven clinical lots of the vaccine to ensure its potency, purity, safety and consistency of its manufacturing. In addition to monitoring upstream-manufactured components, samples of drug substance, final drug product and stability samples were evaluated. This paper focuses on the comparison of the vaccine's critical quality attributes and reviews key indicators of its stability and immunogenicity. Comparable results were obtained by the two laboratories demonstrating sufficient levels of polysaccharide O-acetylation, consistency in size of the bulk conjugate molecules, integrity of the conjugated saccharides in the drug substance and drug product, and acceptable endotoxin content in the final drug product. The freeze-dried vaccine in 5-dose vials was stable based on molecular sizing and free saccharide assays. Lot-to-lot manufacturing consistency was also demonstrated in preclinical studies for polysaccharide-specific IgG and complement-dependent serum bactericidal activity for each serogroup. This study demonstrates the high quality and stability of NmCV-5, which is now undergoing Phase 3 clinical trials in Africa and India.