Table 2.

SLO activities of wild-type and mutant streptococci

Assay contentsFraction of complete lysisa exhibited by bacterial strain:
T18PsSB30-2MGAS166sSBNH5ATCC 27762ATCC 21547
Supernatant0.570.480.560.450.620.78
Supernatant with trypan blueb0.640.500.480.390.580.69
Supernatant with trypan blue and cholesterolc0.050.090.100.070.110.04
  • a Complete lysis was determined by lysing 750 μl of 5% washed sheep erythrocytes in hypotonic saline and adding the mixture to an equal volume of sterile Todd-Hewitt broth.

  • b The concentration of trypan blue was 13 μg/ml.

  • c The concentration of cholesterol was 0.5 mg/ml.