Table II.

Summary of Amino Acid Substitutions and the Binding Characteristics of the Mouse B7-DC Mutants

		Substitutionsb		PD-1 binding
Mutantsa	Sites	Nucleic acids(s)	Amino acid	FACSc	ELISA (%)d
B7-DC				++++	100
D33S	A′ strand	GAC→AGC	D→S	++++	30
S39Y	B strand	AGC→TAC	S→Y	++++	60
E41S	B strand	GAG→AGC	E→S	++++	100
R56S	C strand	AGA→TCT	R→S	+++/++	5
S58Y	C strand	AGT→TAC	S→Y	++++	170
D65S	C′ strand	GAT→AGC	D→S	++++	100
S67Y	C′strand	TCT→TAC	S→Y	+++/++	3
E71S	C′′ strand	GAA→AGC	E→S	+++/++	2
R72S	C′′ strand	AGA→AGC	R→S	++++	60
K84S	D strand	AAG→AGC	K→S	+++/++++	13
H88A	E strand	CAC→GCC	H→A	+++/++++	20
R101S	F strand	CGT→AGC	R→S	+++	7
L103A	F strand	CTG→GCC	L→A	+++	25
I105A	F strand	ATC→GCC	I→A	++	0.5
D111S	G strand	GAC→AGC	D→S	++	0.3
K113S	G strand	AAG→AGC	K→S	−/+	<0.1
T116Y	G strand	ACG→TAC	T→Y	+++/++++	20

^aAmino acids are numbered from the initiation methionine.

^bThe nucleotides or amino acids in front of the “→” symbol were replaced with the corresponding nucleotides or amino acids after the “→” symbol.

^cSee Table I legend for the definition of binding activity to PD-1.

^dSee Table I legend for the calculation of % specific binding activity to PD-1Ig. Each value represents the average of three determinations from each binding curve and the data are representative of four experiments.