Table 4.

Impact of culture conditions (ZnuD expression or not) on the bactericidal activity of sera on a panel of wild-type strains and on derived ΔfHbp, ΔznuD, or ΔznuD-fHbp strains^a

Strain	Geometric mean titer (EU/ml)
	Mouse				Guinea pig
	MH agar		MH-TPEN agar		MH agar		MH-TPEN agar
	CTRL OMVs	ZnuD OMVs	CTRL OMVs	ZnuD OMVs	CTRL OMVs	ZnuD OMVs	CTRL OMVs	ZnuD OMVs
H44/76 (fHbp B/++) strains
WT	<200	2,930	<200	3,446	<200	546	<200	1,055
ΔfHbp	<200	<200	<200	<200	<200	<200	<200	322
ΔznuD	<200	1,778	<200	999	<200	319	<200	206
ΔznuD-fHbp	<200	<200	<200	<200	<200	<200	<200	<200
NZ98/254 (fHbp B/+) strains
WT				3,332				8,646
ΔfHbp				1,899				4,462
ΔznuD				817				<200
ΔznuD-fHbp				<200				<200
M05-240355 (fHbp A/+) strains
WT				932				2,875
ΔfHbp				2,322				7,151
ΔznuD				<200				<200
ΔznuD-fHbp				<200				<200
17540 (fHbp B/−) strains
WT				658				2,525
ΔfHbp				IR				8,069
ΔznuD				<200				<200
ΔznuD-fHbp				<200				<200

^aIR, invalid result; WT, wild type.