TABLE 1.

Chemical compositions of S. Typhi Vi-DT conjugates

Conjugate	AH/DT		Vi concn (μg/ml)	Yield^a (Vi, %)	Vi/DT ratio (wt/wt)	Vi repeating units/DT^b
Conjugate	% (wt/wt)	Molar ratio^b	Vi concn (μg/ml)	Yield^a (Vi, %)	Vi/DT ratio (wt/wt)	Vi repeating units/DT^b
C1	3.5	12	58.05	42	0.80	198
C2	3.1	11	53.83	48	1.06	263
C3	3.2	11	47.00	−^c	0.87	216
C4	2.9	10	50.77	44	0.91	226
C5	3.4	12	56.04	52	1.09	270

↵a Yield was based on the recovery of Vi.
↵b Molar ratio calculated based on the following: DT, Mr = 62,000; Vi repeating unit, Mr = 250; ADH, Mr = 174.
↵c The accidental loss of some material prevented accurate determination of the yield.