Table II.

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

SubstitutionsbPD-1 binding
MutantsaSitesNucleic
 acids(s)Amino
 acidFACScELISA
 (%)d
B7-DC++++100
D33SA′ strandGAC→AGCD→S++++30
S39YB strandAGC→TACS→Y++++60
E41SB strandGAG→AGCE→S++++100
R56SC strandAGA→TCTR→S+++/++5
S58YC strandAGT→TACS→Y++++170
D65SC′ strandGAT→AGCD→S++++100
S67YC′strandTCT→TACS→Y+++/++3
E71SC′′ strandGAA→AGCE→S+++/++2
R72SC′′ strandAGA→AGCR→S++++60
K84SD strandAAG→AGCK→S+++/++++13
H88AE strandCAC→GCCH→A+++/++++20
R101SF strandCGT→AGCR→S+++7
L103AF strandCTG→GCCL→A+++25
I105AF strandATC→GCCI→A++0.5
D111SG strandGAC→AGCD→S++0.3
K113SG strandAAG→AGCK→S−/+<0.1
T116YG strandACG→TACT→Y+++/++++20
  • a Amino acids are numbered from the initiation methionine.

  • b The nucleotides or amino acids in front of the “→” symbol were replaced with the corresponding nucleotides or amino acids after the “→” symbol.

  • c See Table I legend for the definition of binding activity to PD-1.

  • d See 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.