SCALE-UP CONSIDERATIONS AND INVESTIGATION OF THE BIOCONJUGATION OF A SEMI-SYNTHETIC SHIGELLA FLEXNERI TYPE 2A CONJUGATE VACCINE UNDER GMP GUIDELINES

摘要

Currently one of the major causes of diarrheal diseases is attributed to Shigellosis, of which Shigella flexneri type 2a (Sf2a) is most prevalent strain. In search of an effective conjugate vaccine concept, a synthetic mimic of the O antigen (O-Ag) moiety of the Shigella lipopolysaccharides (LPS) was covalently linked to Tetanus toxoid (TT, carrier protein) [1]. Here the grafting of linker/spacer molecule 4-Maleimidobutyric acid N-hydroxysuccinimide ester (GMBS) on TT was optimized through a design of experiments (DoE) approach. Using GMB modified TT conjugates were constructed bearing different loadings of Sf2a (5, 9, 17 & 26). Immunological evaluation of these conjugates led to the finding that the Sf2a:TT molar ratio was critical with an optimum in the range of 17 [2],