Table 1. Screening of sera from HIV-infected subjects to identify elite neutralizers.

		Neutralization titers (ID50a)
No.	Sera/virus	Clade	1	4	5	6	7	8	10	11	12	14	15	17	N16	Z23
1	94UG103	A	785	32	36	69	81	57	31	70	43	61	433	135	30	121
2	92BR020	B	1241	121	219	111	267	108	44	140	194	67	292	185	65	272
3	93IN905	C	986	78	116	124	153	85	141	361	658	122	239	287	91	326
4	M-C-026	C	507	55	66	91	219	72	38	113	300	331	316	112	55	277
5	92TH021	AE	408	53	44	109	95	55	44	41	449	103	1,406	138	57	255
6	SF162	B	5611	9369	76894	5529	51234	1620	2487	1429	9483	2780	18938	14287	4720	22535
7	1196	B	3404	126	161	141	265	189	59	169	105	86	626	927	142	413
8	TRO	B	2556	46	49	89	167	89	54	89	119	61	369	129	63	297
9	JRFL	B	4761	31	40	56	122	974	32	47	47	876	335	180	34	514
10	BG1168	B	224	24	38	37	47	37	<20	35	30	69	170	136	21	120
11	QHO692	B	720	26	27	60	34	39	30	42	35	36	147	90	24	137
12	REJO	B	1206	66	59	126	369	148	39	34	88	302	1,029	196	62	515
13	M-SC-B-006	B	382	21	<20	34	39	81	21	32	59	45	128	109	<20	<100
14	APV-16	B	1101	36	46	66	100	61	56	87	112	39	80	223	90	572
15	M-Chr-B-013	B	381	42	34	57	92	51	43	49	49	40	639	75	23	189
16	PVO	B	2328	37	72	65	84	77	64	50	95	78	332	125	28	439
17	M-A-002	A	291	29	24	32	72	55	28	59	42	46	35	83	22	181
18	M-A-006	A	952	24	22	38	54	40	42	60	131	82	105	104	<20	230
19	M-C-003	C	40	25	<20	31	32	28	22	47	98	41	46	111	23	<100
20	M-C-020	C	1075	32	<20	43	72	39	31	66	111	71	228	99	<20	<100
21	M-D-006	D	2504	28	35	50	60	43	<20	38	20	37	314	78	<20	238
22	M-D-009	D	1465	278	126	222	712	382	140	124	83	144	905	209	135	476
23	JRCSF	B	5933	54	59	100	139	116	<20	46	95	193	788	178	177	402
24	JRCSF	B	4995	43	54	84	137	133	<20	69	120	293	1,045	201	172	385
25	NL43	B	2131	433	271	844	1394	464	97	232	1,852	486	1,182	1,361	769	3598
26	NL43	B	1947	392	203	888	1390	931	93	345	2,448	847	1,733	2,217	591	3172
27	aMLV	—	<20	<20	<20	<20	<20	<20	<20	64	<20	25	23	28	<20	<100

^aThe neutralizing antibody titer (ID₅₀) is defined as the reciprocal of the plasma dilution that produces a 50% inhibition in target cell infection. Values in bold represent neutralization titers that are at least three times greater than those observed against the negative control (aMLV). All clones tested were CCR5 tropic. All human sera/plasma were treated to minimize non-specific backgrounds. Viruses 1–5 are from the Simek panel which defines the EN phenotype [1].