Résumé
Objective:To investigate the improved superantigen activity of SEC2(T20L/G22E) compared with recombinant staphylococcal enterotoxins C 2 ( rSEC2 ).Methods: The proliferation of spleen lymphocytes and T-cell subpopulations induced by rSEC2 and SEC2(T20L/G22E) were examined by WST-1 and flow cytometry separately,and the gene expression of cytokines and Vβspecificities were quantified by real-time PCR.Results: WST-1 and Flow cytometry assays showed that the superantigen activity of SEC2(T20L/G22E) was improved due to enhanced T-cell stimulating potency,resulting in massive activation of T-cells,particularly CD4+and CD8+T-cells.Quantitative real-time PCR assay showed that despite similar Vβspecificities induced by rSEC 2 and SEC2 (T20L/G22E),the quantities of activated T-cells bearing specific Vβwere different,and SEC2(T20L/G22E) could stimulate more gene expression of associated cytokines simultaneously.Conclusion: The results strongly suggested that the increased SEC 2 ( T20L/G22 E)-TCR-binding affinity contributed to more T-cells activation and cytokine release ,which elicit powerful immune activition.