Davinder Gill

Synthesis and immunochemical evaluation of a novel Neisseria meningitidis serogroup A tetrasaccharide and its conjugate

A tetrameric repeating unit of capsular polysaccharide (CPS) of Neisseria meningitidis A (MenA) containing phosphodiester α-(1→6) linkages between N-acetyl-3-O-acetyl-D-mannosamine moieties was synthesized with excellent yield using stereoselective glycosyl phosphorylation strategy. The synthesized tetrasaccharide was conjugated with tetanus toxoid protein (TT) to furnish a glycoconjugate derivative in satisfactory yield. The immunochemical properties of the tetrasaccharide and semi-synthetic glycoconjugate derivative were evaluated for the development of a potential MenA vaccine candidate.

Rational design of heat stable lyophilized rotavirus vaccine formulations

ABSTRACT To develop a safe and efficacious heat-stable rotavirus vaccine, new lyophilized formulations were developed using rotavirus serotypes constituting RotaTeq®. A series of formulation compositions, differing in buffering agents, bulking agents, cryoprotectants, amino acids and divalent cations, were screened for their ability to provide stability to rotavirus serotypes during lyophilization and when stored under elevated temperatures for extended periods. Lead formulations and lyophilization cycles were further optimized. Stability profiles of thus optimized formulations showed their ability to retain the potency of rotavirus for > 36 months at 5°C, 20 months at 37°C, and 7 months at 45°C. The heat-stable lyophilized rotavirus formulations developed met the all critical quality attributes for appearance, heat-stability during storage, moisture content as well as pH, viability and stability after reconstitution and has great potential to be used as vaccine candidates for improving access in low-income countries.

Rotavirus vaccine efficacy: current status and areas for improvement

ABSTRACT The difference noted in Rotavirus vaccine efficiency between high and low income countries correlates with the lack of universal access to clean water and higher standards of hygiene. Overcoming these obstacles will require great investment and also time, therefore more effective vaccines should be developed to meet the needs of those who would benefit the most from them. Increasing our current knowledge of mucosal immunity, response to Rotavirus infection and its modulation by circadian rhythms could point at actionable pathways to improve vaccination efficacy, especially in the case of individuals affected by environmental enteropathy. Also, a better understanding and validation of Rotavirus entry factors as well as the systematic monitoring of dominant strains could assist in tailoring vaccines to individual’s needs. Another aspect that could improve vaccine efficiency is targeting to M cells, for which new ligands could potentially be sought. Finally, alternative mucosal adjuvants and vaccine expression, storage and delivery systems could have a positive impact in the outcome of Rotavirus vaccination.