| Objective: To investigate the effect of staphylococcal enterotoxin A (SEA) on thedistribution and clonal expansion of TCR Vβsubfamilies and the cytotoxicityof T cells stimulated by PML-RARαfusion peptide.Methods: Peripheral blood mononuclear cells were cultured with PML-RARαfusionpeptide or SEA or both of them for 20 days; and a comparison of ConA withSEA was set. The distribution and clonal expansion of TCR Vβsubfamilies ofinduced T cells were examined by RT-PCR-GeneScan. Meanwhilecytotoxicities of the induced T cells against NB4 and K562 leukemia cell lineswere examined by Cell Counting Kit-8 (CCK-8). Both CD4 and CD8 surfacemolecules from the harvest cells were detected within the CD3~+ T cells byflow cytometry (FCM) as well. And also cytokine levels of IFN-γ, IL-4 andIL-10 in the cultured supernatants were measured by Enzyme-LinkedImmunosorbent Assay (ELISA).Results: Restricted expressions and clonal expansions of TCR Vβsubfamilies of T cellswere identified after induction by PML-RARαpeptide both in and without thepresence of SEA for 20 days. The cytotoxicity assay showed that T cellsinduced by PML-RARαpeptide with SEA had higher kill rate against NB4cells than that of induced by the inducers separately. The FCM assay showedthat CD8~+ T cells were in priority after induced by PML-RARαpeptidewhether with SEA or not, while it came out to be an equal rate between CD4~+and CD8~+ T cells with the induction of SEA only. And the Th1-type cytokineof IFN-γhad higher levels than that of the Th2-type cytokines (IL-4 andIL-8) in the cultured supernatants induced by PML-RARαpeptide, SEA andboth of them.Conclusion: PML-RARαpeptide can induce specific T cells with clonal expansions ofTCR Vβsubfamilies. These T cells have strong antileukemia effect through their cytotoxicities against NB4 cells. And SEA can play a costimulating rolewith PML-RARαpeptide. It strengthens the effect of the peptide on itsinduction action. |
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