Purification and characterization of group A streptococcal pyrogenic exotoxin type C

Abstract

Group A streptococcal pyrogenic exotoxin (SPE) type C was partially purified by differential solubility in ethanol and acetate-buffered saline. Toxin prepared in this way consisted of protein and hyaluronic acid. After removal of hyaluronic acid, the toxin remained pyrogenic, enhanced susceptibility of rabbits to lethal endotoxin shock, was stable when treated with acid, base, or pepsin, but was inactivated by heat. Toxin further purified by thin-layer isoelectric focusing was pyrogenic and enhanced the susceptibility of rabbits to lethal endotoxin shock. Purified type C toxin appeared homogeneous when tested by Ouchterlony immunodiffusion and migrated as a single protein band in isoelectric focusing polyacrylamide gels (isoelectric point, 6.7) and sodium dodecyl sulfate-polyacrylamide gels (molecular weight, 13,200). The purified toxin was antigenically distinct from A and B SPE, and antisera raised against the purified toxin neutralized pyrogenic activity. The amino acid composition was determined.

Streptococcal erythrogenic toxin type C is not a phosphorylated protein. Description of two different purification procedures and investigation of its phosphorylation state

“…As has been shown by N-terminal amino acid sequencing the ETC investigated in this work is identical to that decribed by Schlievert et al [26]. According also to data of Goshorn et al [11], the signal peptide of ETC is cleaved at position 28 after serine.…”

“…An adequate purification scheme for erythrogenic toxin type C (ETC) is described in this paper. It enabled us, contrary to other already published procedures according to Schlievert et al [26] and Ozegowski et al [21], to obtain highly purified ETC practically in one step and diminish the influence of dephosphorylating activities.…”

Purification and properties of an extracellular blastogen produced by group A streptococci.

“…Another group of mitogenic proteins that are produced by group A streptococci are the streptococcal pyrogenic exotoxins (SPE), also known as the streptococcal erythrogenic toxins (7)(8)(9). Three distinct species of SPE exist with mol wt of 8,000, 17,500, and 13,000, respectively, for SPE A, B, and C. The molecular weight and electrophoretic mobility of SPE A and C are clearly different from blastogen A. Exotoxin B, however, is similar in mobility to blastogen A and has an identical molecular weight.…”

The role of streptococcal toxins in disease

“…Streptococcal pyrogenic exotoxins (SPE) were discovered as the proteins responsible for the rash in scarlet fever (Dick and Dick 1924). Three toxins were later defined which appeared to have superantigenic properties : SPE A (Kim and Watson 1970), SPE B (Barsumian et al 1978) and SPE C (Schlievert et al 1977). Further superantigens have also been identified including SPE D, SPE F, streptococcal superantigen SPE-X and Streptococcus pyogenes mitogen.…”