Similarities between Complement-mediated and Streptolysin S-mediated Hemolysis

Abstract

The oxygen-stable hemolysin streptolysin S (SLS) of Streptococcus pyogenes is encoded in part by the pel/ sagA gene product. Antibodies to a synthetic peptide from the C terminus of the Pel/SagA open reading frame inhibited hemolysis mediated by both culture supernatants from multiple M serotypes of S. pyogenes isolates or a commercially available SLS preparation. Analysis of the SLS-mediated hemolytic reaction demonstrated that it was temperature-and concentration-dependent. Like complement-mediated hemolysis it conforms to the prediction of a one-hit mechanism of hemolysis. A number of intermediates in the SLS-mediated hemolysis of sheep erythrocytes could be distinguished. SLS could bind to erythrocytes below 17°C; however, lysis could only occur at temperatures >23°C. Following binding of SLS and washing, a papain-sensitive intermediate could be distinguished prior to insertion of the SLS complex into the erythrocyte membrane, which resulted in formation of a transmembrane pore and led to irreversible osmotic lysis of the cell. These intermediates were similar to those described previously during complementmediated hemolysis.

The pathogenic equine streptococci

“…Production of this bacteriocin-like cytotoxin is encoded by a 9-gene locus, and biologic activity requires stabilization by association with a carrier molecule such as double stranded RNA or albumin. Binding of the streptolysin S complex to erythrocytes results in formation of a transmembrane pore and irreversible osmotic lysis of the cell, a process similar to complement-mediated hemolysis [13]. Damage to keratinocytes has also been noted.…”

Streptolysin S Promotes Programmed Cell Death and Enhances Inflammatory Signaling in Epithelial Keratinocytes during Group A Streptococcus Infection

“…The cytotoxic properties of SLS have been well documented in a variety of cell types and subcellular structures in vitro, as well as in vivo using murine skin infection models, but the mechanism of SLS activity is not well understood (6)(7)(8)(9)(10)(11)(12)(13)(14)(15)(16)(17)26). An understanding of the physiological role of this toxin during infection is complicated by reports of its varied effects in different cell types and tissues.…”

“…These modifications have been shown to be critical for the cytolytic activity of SLS-like peptide toxins (7,8). The cytolytic activity of SLS has historically been attributed to its ability to induce osmotic deregulation and subsequent lysis through an unknown mechanism, and the toxin has been reported to cause membrane rupture in a variety of eukaryotic cell types and subcellular structures (6,(9)(10)(11)(12)(13)(14)(15)(16)(17). The lytic activity of SLS is often measured via red blood cell (RBC) lysis because it is the GAS toxin primarily responsible for the characteristic hemolytic zone that surrounds bacterial colonies on blood agar (18).…”

Implementation of a Permeable Membrane Insert-based Infection System to Study the Effects of Secreted Bacterial Toxins on Mammalian Host Cells

“…This protocol can be adapted for the study of other secreted bacterial virulence factors as well as alternative host cell types. This recently developed system provides several advantages over experimental methods that utilize purified toxins or filtered bacterial supernatants [1][2][3]8,[18][19][20] . The permeable membrane insert-based system provides a constantly maintained dose of the relevant bacterial toxin to host cells as it is produced, which allows maximal toxin activity to be maintained and also increases consistency between experiments.…”

“…In cases where the preparation of purified toxins or other secreted factors is either complex or not possible, mechanisms to elucidate the function of these products have traditionally been studied through the preparation of filtered bacterial supernatants, which are then applied to host cells [18][19][20] . There are several challenges associated with this technique.…”