Lck-independent triggering of T-cell antigen receptor signal transduction by staphylococcal enterotoxins

Shou Yamasaki, Makoto Tachibana, Nobukata Shinohara, Makio Iwashima

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    Abstract

    Superantigens (SAgs) activate T-cells in a manner specific to the Vβ region of the T-cell antigen receptor. Stimulations by SAgs provoke drastic T-cell activation that leads to programmed cell death or the anergic state of responding cells. To characterize the signal transduction pathway initiated by SAgs, mutant lines derived from the human leukemic T-cell line Jurkat were tested for their reactivities against prototypic SAgs, staphylococcal enterotoxins. The J.CaM1.6 cell line, which lacks Lck expression and lost reactivity against T-cell antigen receptor-mediated stimulation, was activated by staphylococcal enterotoxins in a manner indistinguishable from the Jurkat cell line. In contrast, the J.45.01 cell line, which lacks expression of functional CD45, showed severely impaired reactivity. The role of Lck appears to be replaced by another Src family protein-tyrosine kinase, Fyn. In J.CaM1.6 cells, Fyn was rapidly phosphorylated and activated after staphylococcal enterotoxin treatment. The kinase-inactive mutant of Fyn significantly suppressed the reactivity against staphylococcal enterotoxin E in J.CaM1.6 cells, and the expression of the active form of Fyn reconstituted reactivity against staphylococcal enterotoxin E in J.45.01 cells. These results demonstrate that SAgs activate T-cells in an Lck-independent pathway and that Fyn plays a critical role in the process.

    Original languageEnglish
    Pages (from-to)14787-14791
    Number of pages5
    JournalJournal of Biological Chemistry
    Volume272
    Issue number23
    DOIs
    Publication statusPublished - Jun 6 1997

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    All Science Journal Classification (ASJC) codes

    • Biochemistry
    • Molecular Biology
    • Cell Biology

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