Table 3.

Superantigenicity of wild-type SPE A and mutants with use of rabbit splenocytesa

Protein testedMean cpm ± SE (103) at the following dose (μg):
101.00.10.010.0010.0001
Wild-type SPE A211 ± 5.3181 ± 8.6131 ± 8.5105 ± 1.679 ± 1.055 ± 4.9
N20D/C98S13 ± 0.913 ± 0.715 ± 1.110 ± 0.814 ± 1.313 ± 1.1
N20D/D45N/C98S23 ± 4.020 ± 2.120 ± 2.817 ± 2.118 ± 1.818 ± 2.3
Q19H/N20D/L41A/L42A/D45N/C98S18 ± 0.819 ± 1.419 ± 2.018 ± 1.013 ± 1.417 ± 1.1
  • a Rabbit splenocytes (2 × 105/well) were incubated with proteins, in quadruplicate, for 3 days at 37°C with 7% CO2, and then 1 μCi of [3H]thymidine was added to each well. DNA was harvested after another 24 h of incubation, and counts per minute were determined by scintillation counting. The background was 17 ± 0.4 cpm.