Table 1.

Physical characteristics of Vi-CRM₁₉₇ conjugates of different Vi size tested in mice

Conjugate	Vi average number of repeating units*	Vi % OAc	Vi to CRM197 ratio (wt/wt)	% free Vi
9.5-kDa fVi-CRM197	37	66	0.33	10.6
22.8-kDa fVi-CRM197	88	80.5	0.52	<5†
42.7-kDa fVi-CRM197	165	95	0.64	13.7
82.0-kDa fVi-CRM197	317	95	1.33	17.2
165-kDa Vi-CRM197	636	95	1.27	<13†

^*Calculation based on Vi monomer molecular weight of 259 corresponding to O-acetylated (OAc) and free acid forms.

^†% values refer to the ratio between the minimum quantifiable amount of free Vi detected by high-performance anion exchange chromatography coupled with pulsed amperometric detection to the total amount of PS in the conjugate.