Table 2

Activation and inhibition by AIPs and an AIP analog

RN9222 (CA1-I)RN9366 (CA1-II)RN9372 (CA2-II)RN9367 (CA2-I)
Activation EC50, nM
 Group I AIP40 ± 923 ± 7
 Group II AIP34 ± 6 28 ± 14
Inhibition IC50, nM*
 Group I AIP26 ± 7135 ± 52
 Group II AIP90 ± 3078 ± 12
RN9222 (CA1-I)*RN9372 (CA2-II)*RN8465 (Group III)RN9371 (CA4-IV)
Inhibition IC50, nM for Group II AgrD truncated thiolactone
 Group II AIP, truncated272 ± 67 209 ± 39 10 ± 1188 ± 50
  • All values include an error of ±SEM determined from at least two assays. 

  • * These values were obtained with a constant concentration, 100 nM, of the autologous (activating) AIP. 

  • All results determined for the Group III strain RN8465 were from HPLC analysis of δ toxin. All other results were from β-lactamase assays. 

  • Group IV supernatant was used as a source of activating AIP in these analyses.