Impact of cathelicidin cleavage by SpeB on Streptococcus pyogenes CovRS signaling.

In vitro genetic and biochemical study using Streptococcus pyogenes strains

“Using a genetic approach, we show that the presence SpeB did not significantly impact the killing of Spy by LL-37 relative to other known resistance factors.”

Streptococcus pyogenes (Group A Streptococcus) and the antimicrobial peptide LL-37

“One of the microbes with the potential to cleave LL-37 is Streptococcus pyogenes (Spy; Group A Streptococcus)9,10.”

Experiments included 2-hour exposure for survival assays and 15-hour growth for reporter measurements

“After 2 h of exposure, there was no significant difference in survival between the two strains (Fig. 2B).”

The presence of SpeB did not significantly impact the killing of Streptococcus pyogenes by LL-37 compared to other resistance factors.

“Using a genetic approach, we show that the presence SpeB did not significantly impact the killing of Spy by LL-37 relative to other known resistance factors.”

The CovRS two-component system maintains sensitivity to LL-37 fragments generated by SpeB cleavage.

“Furthermore, while SpeB cleaves LL-37, CovRS maintains sensitivity to LL-37 fragments.”

SpeB cleavage of LL-37 does not negatively impact virulence factor regulation in Streptococcus pyogenes.

“These results indicate that SpeB cleavage of LL-37 does not negatively impact virulence factor regulation in Spy.”

It remains unclear if specific regions of LL-37 mediating immune regulatory activities are destroyed by SpeB proteolysis.

“This would be informed by future studies that map whether specific regions of LL-37 mediate these activities, and if they would be destroyed by SpeB proteolysis.”