Table III.

Summary of epitope mapping data using FcγRIIa mutants

	Residue Numbera						Binding Activity
Receptor Construct	90	113	130	134–138	162	163	8.7	IV.3	X63-21	HAGG
FcγRIIa-LR WT	W	W	Q	HLDPT	L	F	++	++	−	++
FcγRIIa-HR WT	․	․	․	R․ ․ ․ ․	․	․	++	++	−	ND
FcγRIIb WT	․	․	K	RS ․ ․ N	․	․	++	−	++	++
FcγRIIa-LR W90A	A	․	․	․ ․ ․ ․ ․	․	․	++	++	ND	+
FcγRIIa-LR W90A,W113A	A	A	․	․ ․ ․ ․ ․	․	․	−	++	ND	±
FcγRIIa-LR Q130K	․	․	K	․ ․ ․ ․ ․	․	․	++	++	ND	++
FcγRIIa-LR L135S	․	․	․	․ S ․ ․ ․	․	․	++	−	−	++
FcγRIIa-HR L135S	․	․	․	RS ․ ․ ․	․	․	++	−	++	++
FcγRIIa-HR T138N	․	․	․	․ ․ ․ ․ N	․	․	++	++	ND	++
FcγRIIa-HR L135S, T138N	․	․	․	․ S ․ ․ N	․	․	++	−	++	++
FcγRIIa-HR L162N, F163V	․	․	․	․ ․ ․ ․ ․	N	V	±	++	ND	+

^a“․” indicates residues that are unaltered from the wild-type sequence of FcγRIIa-LR, FcγRIIa-HR, or FcγRIIb. Residue W113 is essential to the 8.7 epitope. Residues L135 and R134-S135 are essential to the IV.3 and X63-21/7.2 epitopes in FcγRIIa and FcγRIIb, respectively.

⁺⁺maximal binding equivalent to WT FcγRIIa;

⁺intermediate binding;

^±weak detectable binding;

⁻undetectable binding over background, as exemplified in Fig. 4 and Supplemental Fig. 3;

ND, no data.