TABLE 2.

Effect of variations in LPS structure on sensitivity to bactericidal activity of rabbit sera

Variation	Isolate	Genotype	Phenotype (% of colonies reactive with:)		Bactericidal titer of rabbit serum:
			HASa	4C4	ME46b	ME48	ME53	ME56	ME60	ME88
Mutation of lic1 locus	KW20-MI	Wild type	13.8	NDc	>1,280d	320	160	<20	<20	>1,280
	KW20-H3	Wild type	96.5	ND	160	80	80	<20	<20	160
	H446	lic1	0	ND	>1,280	1,280	640	<20	<20	>1,280
	H491	lic1(Con)	100	ND	20	20	<20	<20	<20	20
Phenotypic variation of ChoP and galα1,4gal	KW20-MI		2.9	<1	>1,280	1,280	>1,280	<20	<20	>1,280
	H418		95.5	<1	40	40	40	<20	<20	<20
	H419		2.5	<1	80	20	40	<20	<20	40
	H420		2.9	92.2	>1,280	>1,280	>1,280	<20	<20	>1,280

^aThe expression of the phase-variable LPS epitopes ChoP and galα1,4gal was determined for each culture by colony immunoblotting by using monoclonal antibodies HAS (for ChoP) and 4C4 I(for galα1,4gal), as previously described previously (18). 

^bRabbits were immunized with proteins cloned from H. influenzae KW20 (5). The predicted sequences of these proteins are available from the TIGR database (www.tigr.org). Serum ME46, locus HI 0541; ME48, HI 0947; ME53, HI 1119; ME56, HI 1373, ME60, HI 1251. Serum ME88 is from a rabbit immunized with OM prepared from KW20. 

^cND, not determined (monoclonal antibody 4C4 does not bind to KW20 [15]). 

^dBactericidal titer.