TABLE 4.

Serum ID₅₀ titers in the absence and presence of MPER-derived peptides

Serum	Sample fraction	Virus	ID50 for peptide:				% Neutralization inhibited by test peptide:b
			Mocka	2F5.01	4E10.22	MPR.03	2F5.01	4E10.22	MPR.03
1	Untreated plasma	HIV-2/C1	<20	<20	<20	<20
	Untreated plasma	HIV-2/C1	22	21	10	10	0	55	55
6	Untreated plasma	HIV-2/C1	40	51	20	10	0	50	75
	Untreated plasma	HIV-2/C1	55	49	21	10	11	62	82
	gp120 Ab-depleted fractionc	SF162	59	63	77		0	0
19	Untreated plasma	HIV-2/C1	281	276	42	72	2	85	74
	Untreated plasma	HIV-2/C1	243	183	69	110	25	72	55
	Untreated serum	HXBc2	1,005	720	628		28	38
	gp120 Ab-depleted fraction	HXBc2	82	79	20		4	76
	gp120 Ab-depleted fraction	SF162	<20	<20	<20
20	Untreated plasma	HIV-2/C1	563	512	34.8	24.9	9	94	96
	Untreated plasma	HXBc2	4,401	5,447	1,528		0	65
	gp120 Ab-depleted fraction	HXBc2	169	177	20		0	88
	gp120 Ab-depleted fraction	SF162	449	429	40		4	91
	gp120 Ab-depleted fraction	BaL.01	25	20	27		20	0
	Untreated plasma	JRFL	1,286	1,583	977		0	24
	gp120 Ab-depleted fraction	JRFL	40	56	10		0	75
30	Untreated plasma	HIV-2/C1	651	600	250	486	8	62	25
	Untreated plasma	HIV-2/C1	928	426	372	737	54	60	21
45	Untreated plasma	HIV-2/C1	20.1	20	10	10	0	50	50
	Untreated plasma	HIV-2/C1	58.3	71.7	40	40	0	31	31
	gp120 Ab-depleted fraction	HXBc2	56	53	44		6	21
	gp120 Ab-depleted fraction	SF162	179	106	266		41	0
B7B5	Untreated plasma	HIV-2/C1	3,204	1,659	487	867	48	85	73
	gp120 Ab-depleted fraction	HXBc2	3,953	3,766	5,413	4,479	5	0	0

^aMock peptide (defined as an equivalent volume of PBS) was used as a negative control.

^bIndicator of peptide-specific neutralizing antibody response; calculated as [1 − (ID₅₀ with test peptide)/ID₅₀ with mock peptide)] × 100. Values higher than 50% are shown in boldface type.

^cThe fraction of serum that was adsorbed with gp120-coupled Dynabeads prior to the neutralization assay.