Isolation of a new superantigen with a potent mitogenic activity to murine T cells from Streptococcus pyogenes

Eiji Nemoto, Hidemi Rikiishi, Shunji Sugawara, Shigefumi Okamoto, Keiji Tamura, Yasuo Maruyama, Katsuo Kumagai

Research output: Contribution to journalArticlepeer-review


A mitogenic substance on murine lymphocytes was detected in the culture supernate of Streptococcus pyogenes type 12 strain. This substance had a molecular weight of 28,000 and pI 9.2, and was designated as S. pyogenes mitogen (SPM). The proliferative response of C3H/HeN spleen cells began at 1 ng ml-1 and reached a maximal response at 100 ng ml-1 of SPM for 4 days culture. Anti-Thy1.2 mAb and complement-treated spleen cells abrogated the proliferative response to any dose of SPM. Although the anti-major histocompatibility complex class I mAbs had no blocking effect on proliferation by SPM, this proliferation was substantially inhibited by the addition of either anti-I-A or anti-I-E mAb, and complete inhibition was produced by the addition of both mAbs. Fixed antigen-presenting cells still induced T cell proliferation by SPM. A significant expansion of T cells bearing Vβ13 T-cell receptor was observed up to 73% among the Thy1.2+ cells in cultures stimulated with SPM, indicating expansion in a Vβ-specific manner. Immunoblotting of IEF-separated proteins showed that anti-streptococcal pyrogenic exotoxin (SPE) C reacted with a protein of pI 6.9 and anti-SPEB did not show any reactivity. SPEA was reported to expand Vβ8.1 and 8.2 bearing murine T cells, and SPM did not. SPM also exhibited potent mitogenic activity on human T cells and Vβ21+ T cells were selectively expanded. These results lead to the conclusion that SPM was neither SPEA, B nor C, but a new protein belonging to a group of streptococcal superantigens with activity on not only human but also murine lymphocytes.

Original languageEnglish
Pages (from-to)81-91
Number of pages11
JournalFEMS Immunology and Medical Microbiology
Issue number2-3
Publication statusPublished - 1996 Sept


  • Murine Vβ13 T cell
  • Streptococcus pyogenes
  • Superantigen

ASJC Scopus subject areas

  • Immunology and Allergy
  • Microbiology
  • Immunology
  • Microbiology (medical)
  • Infectious Diseases


Dive into the research topics of 'Isolation of a new superantigen with a potent mitogenic activity to murine T cells from Streptococcus pyogenes'. Together they form a unique fingerprint.

Cite this