Table 2.

Superantigenicity of wild-type SPE A and mutants with use of human PBMCsa

Protein testedMean cpm ± SE (103) at the following dose (μg):
1010.10.010.0010.0001
Wild-type SPE A119 ± 2.7103 ± 14135 ± 10126 ± 13142 ± 8.7156 ± 3.9
N20D/C98S16 ± 1.724 ± 3.321 ± 0.719 ± 0.721 ± 0.821 ± 0.6
N20D/D45N/C98S25 ± 4.027 ± 1.221 ± 1.520 ± 2.422 ± 1.522 ± 2.3
Q19H/N20D/L41A/L42A/D45N/C98S20 ± 1.723 ± 0.520 ± 3.515 ± 2.018 ± 1.320 ± 3.0
  • a Human PBMCs (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 16 ± 0.5 cpm for quadruplicate wells containing lymphocytes only.