Table 1

Effect of LAG-3 mutations on LAG-3/class II MHC interaction

MutationLocalization of residueAnti-LAG-3 mAb reactivity Level of LAG-3 expressionRelative adhesion
17B411E315A9
Wt+++1.01
GALNeg. control00.09  ±  0.06
Q13AAB+++1.00.92  ±  0.06
D30ABC+++0.810.41  ±  0.17
H56AExtra loop++0.70.45  ±  0.28
H56FExtra loop++0.760.89  ±  0.36
H63AExtra loop+++0.890.83  ±  0.10
H63FExtra loop+++0.950.91  ±  0.18
R73EExtra loop++1.13.25  ±  1.00
R75AExtra loop+++0.674.20  ±  0.66
R75EExtra loop+++1.44.10  ±  0.90
R76EExtra loop+++0.852.95  ±  1.00
Y77FC"+++0.750.05  ±  0.06
R88AC"D+++0.820.18  ±  0.07
R103ADE+++0.930.49  ±  0.03
R107KE+++1.11.02  ±  0.19
D109EE+++0.810.18  ±  0.19
R115AEF+++0.740.23  ±  0.05
D133A/R134AFG+++0.990.78  ±  0.24
D225LFG (D2)+++0.850.89  ±  0.13
(D2)D2 deletion+++0.60.11  ±  0.09
(54/66)Extra-loop deletion±+0.60.08  ±  0.12
  • The table shows the binding of 51Cr-labeled Daudi B cells to COS-7 cells expressing LAG-3 mutants. All mutations were in Ig-like domain 1 except for D225L. Nonspecific binding to control-transfected cells was not subtracted from experimental mean cpm. The results expressed relative to wt value should be compared with the background level as defined by the GAL (the LAG-3 insert cloned in reverse orientation in pCDM8)-transfected control cells. Relative expression level of mutant LAG-3 versus wtLAG-3 is also shown. The level of mutant LAG-3 expression was studied with 15A9 reactivity, and relative mAb reactivity was measured as follows: +, 1–0.6; +/−, 0.2–0.6; −, 0–0.2.