title: Purification and characterization of erythrogenic toxins of Streptococcus pyogenes. VI. Mitogenic activity of isoelectrically focused erythrogenic toxin preparations and culture supernatants of group A streptococci.
abstract: Isoelectric focusing (IF) was used to separate erythrogenic toxins (ET) type A, B and C from concentrated culture filtrates of Streptococcus pyogenes strains. The ET's were identified by their mitogenic activity on human lymphocytes in the lymphocyte transformation test: purified ET type A appeared at pH 5.3, ET type C at pH 6.8 and ET type B at pH 7.5 to 8.5; the ET type B was only biologically active when PAGE IF was used. IF on Sephadex G 100 failed to yield active B toxin. The application of as little as 0.1 micrograms ET type A to an isoelectric focusing gel was still sufficient to detect a mitogenic peak in the eluates. ET type A was identified in nine out of 10 culture filtrates, ET type C in 4 out of 10. Detection of ET type B (identical with streptococcal proteinase proenzyme) in culture filtrates after IF proved to be difficult. Here the pH of cultivation media and the autocatalytic conversion of streptococcal proteinase proenzyme to activated proteinase have to be considered.
mesh_terms: D001426:Bacterial Proteins; D001427:Bacterial Toxins / Q000302:isolation & purification* / Q000502:physiology; D005098:Exotoxins; D007525:Isoelectric Focusing; D008213:Lymphocyte Activation / Q000187:drug effects*; D008214:Lymphocytes / Q000187:drug effects; D008565:Membrane Proteins; D008934:Mitogens / Q000502:physiology; D013297:Streptococcus pyogenes / Q000276:immunology*
chemical_list: D001426:Bacterial Proteins; D001427:Bacterial Toxins; D005098:Exotoxins; D008565:Membrane Proteins; D008934:Mitogens; C117980:SpeA protein, Streptococcus pyogenes; C027951:erythrogenic toxin