Table 2.

Epitope mapping of V3 mAbs

MAb	Apparent affinity (%)a relative to wild-type gp120JRCSF for indicated V3 mutants located in noted V3 segments
	baseb			stem			tip										stem
	R298A	P299A	N301A	N302A	R304A	K305A	S306A	I307A	H308A	I309A	P313A	R315A	F317A	Y318A	T319A	T320A	E322A	D325A
19b	71	146	113	66	5	23	167	0.3	128	54	4	7	0.3	0.3	72	123	95	201
39F	66	156	148	73	66	0.5	40	6	75	50	108	95	75	119	107	164	104	160
CO11	130	258	58	114	74	79	190	84	17	71	0.2	0.2	79	162	97	120	90	177
F2A3	76	168	135	114	86	11	90	50	40	219	38	0.1	211	257	161	176	148	223
F530	57	218	151	59	11	7	143	30	55	59	36	78	158	158	103	171	162	89
LA21	77	118	124	97	130	135	128	216	41	197	0.4	54	56	29	137	220	66	169
LE311	68	140	109	78	64	2	127	44	35	106	3	3	136	127	122	103	108	138
B4e8	79	96	124	85	88	83	87	74	88	23	91	3	49	76	81	127	77	117

^aApparent affinities were determined as the antibody concentration at half-maximal binding based on ELISA binding curves using the program Graphpad Prism (v.4.0). Apparent affinities relative to wild-type gp120_JRCSF were calculated with the formula (apparent affinity for wild type/apparent affinity for mutants) ×100%. Red: <10% relative binding affinity; blue: >10% to <50% relative binding affinity; white: >50% to <200% relative affinity between; black: >200% relative affinity. The mapping results for mAb B4e8 are taken from (Pantophlet et al., 2007). Residue numbering is based on the HXB2 reference sequence (http://www.hiv.lanl.gov/). The mutants are arranged from the N- to C-terminal portion of the V3 region (left to right).

^bV3 is divided into 3 structural segments based on the V3 structure in the context of gp120 (Huang et al., 2005): (I) the base (residues 296–300 (N-terminal portion) and 326–331 (C-terminal portion)), (II) the stem (residues 301–305 (N-terminal portion) and 321–325 (C-terminal portion)), and (III) the tip (residues 306–320).