Specificity of OPK activity of 30-valent rabbit antiserum as determined by recombinant M protein inhibition assaysa

Strain of test bacteriaMaximum percent killing (% inhibition) after incubation with:
No inhibitorHomologous MHeterologous M
M5590 (100)56 (5)b
M1860 (100)100 (0)c
  • a Inhibition assays were performed in quadruplicate using the same concentration of antiserum in each reaction mixture. The final dilution of rabbit antiserum was 1:8 for M5 bacteria, and the final dilution was 1:16 for M1 bacteria.

  • b The heterologous antigen was 10 µg rM3, which had been preincubated with the rabbit antiserum prior to addition to the reaction mixture.

  • c The heterologous antigen was 10 µg rM5.