Cathelicidin LL-37 in severe Streptococcus pyogenes soft tissue infections in humans.

Antimicrobial Peptide LL-37 Presence of the Human Cationic Growth in Iron Starvation and in the CovRS Mediates Streptococcus pyogenes

Group A Streptococcal M1 Protein Sequesters Cathelicidin to Evade Innate Immune Killing.

The antimicrobial peptide LL-37 is generated upon proteolytic cleavage of cathelicidin and limits invading pathogens by directly targeting microbial membranes as well as stimulating innate immune cell function. However, some microbes evade LL-37-mediated defense. Notably, group A Streptococcus (GAS) strains belonging to the hypervirulent M1T1 serogroup are more resistant to human LL-37 than oth...

SIC, a secreted protein of Streptococcus pyogenes that inactivates antibacterial peptides.

Some isolates of the significant human pathogen Streptococcus pyogenes, including virulent strains of the M1 serotype, secrete protein SIC. This molecule, secreted in large quantities, interferes with complement function. As a result of natural selection, SIC shows a high degree of variation. Here we provide a plausible explanation for this variation and the fact that strains of the M1 serotype...

Induction of group A Streptococcus virulence by a human antimicrobial peptide.

Group A streptococci (Streptococcus pyogenes or GAS) freshly isolated from individuals with streptococcal sore throat or invasive ("flesh-eating") infection often grow as mucoid colonies on primary culture but lose this colony appearance after laboratory passage. The mucoid phenotype is due to abundant production of the hyaluronic acid capsular polysaccharide, a key virulence determinant associ...

Cutaneous injury induces the release of cathelicidin anti-microbial peptides active against group A Streptococcus.

Cathelicidins are a family of peptides thought to provide an innate defensive barrier against a variety of potential microbial pathogens. The human and mouse cathelicidins (LL-37 and CRAMP, respectively) are expressed at select epithelial interfaces where they have been proposed to kill a number of gram-negative and gram-positive bacteria. To determine if these peptides play a part in the prote...