Table 3.

Serum bactericidal activity of pooled mouse sera against MenX strains and anti-MenX IgG GMT ELISA units 95% confidence interval 14 d after the second (post 2) and third (post 3) injection of MenX–CRM₁₉₇ conjugate vaccines and control

Group	SBA titers				Standard ELISA		High-avidity ELISA
	Pooled sera post 2	Pooled sera post 3			Sera post 2	Sera post 3	Sera post 2	Sera post 3
	5967 (ST 750)	5967 (ST 750)	BF7/07	Kenya 1/06
PBS + adjuvant	<16	<4	<4	<4	2	2	2	2
MenXOX–CRM197	1,024	4,096	4,096	2,048	1,857	1,810	69.8	404.6
MenX–NH2–SIDEA–CRM197	128	4,096	4,096	2,048	276	1,447	6.4	482.7
MenX–ADH–SIDEA–CRM197	1,024	4,096	4,096	2,048	1,313	1,816	80.1	836.1
MenX–ADH–SIDEA–CRM197 (0.1 μg)	512	4,096	2,048	2,048	277.5	2,208	49.6	576.8

Female BALB/c (5–6 wk old) mice were immunized three times at 2-wk intervals with MenX–CRM₁₉₇ conjugate vaccines at 1-μg dose. MenX–ADH–SIDEA–CRM₁₉₇ was also tested at 0.1-μg dose. All vaccines were tested with aluminum phosphate as adjuvant. Bactericidal titers are defined as the reciprocal serum dilution that gives a 50% decrease of colony-forming units after 60-min incubation in the reaction mixture, compared with the mean number of colony-forming units in the control reactions at time 0.