Intracellular Cytokines Produced by Stimulated CD3+ Cells from Chronic Myeloid Leukemia Patients

Preparation and evaluation of the adjuvant effect of curdlan sulfate in improving the efficacy of dendritic cell-based vaccine for antitumor immunotherapy

Dendritic cell (DC) vaccine immunotherapy applies tumor antigens or tumor cell lysate (TCL)-pulsed DCs to induce an antigen-specific immune response to attack cancer cells. However, tumor antigen alone has limited immunostimulatory effects, and so immunostimulants are needed to prepare mature DCs. In our previous study, curdlan sulfate (CS) showed potent adjuvant properties with the HBV vaccine; therefore, we attempted to use CS to mature TCL-pulsed DCs. We first prepared four CSs (CS1-CS4) with different sulfation (S) degrees and molecular weights (MWs), then studied the structure-activity relationship of CS in vitro and finally screened CS3 (14.316% S content and 30.66 kDa MW) as the DC vaccine adjuvant. An in vivo study showed that a DC vaccine adjuvanted with CS3 significantly prolonged the survival of tumor-bearing mice, reduced tumor burden and inhibited tumor growth. The CS3-adjuvanted DC vaccine increased CD80, MHC-I and MHC-II expression, promoted CD8⁺ T cell infiltration, upregulated TNF-α and IFN-γ transcription, and downregulated TGF-β transcription in tumor tissues. A preliminary mechanism study showed that CS activated DCs mainly via the TLR4 and TLR2 signalling pathways. Based on these results, we concluded that CS3 is a potential adjuvant for DC vaccines and is worth studying for tumor immunotherapy.

Cytokine Syntheses by T-Cell Subsets From Chronic Myeloid Leukemia Patients: Relationship Between Pre-Treatment Levels and Response to Imatinib Therapy

Background

Although T-cell cytokine's role in the long-term control of chronic myeloid leukemia (CML) is well established, previous studies showed contradicting results regarding imatinib (IM) effect on the endogenous T-cell function by IM. The purpose of this study was to determine the relation between the endogenous T-cell function prior to therapy and the degree of response to IM therapy in CP CML. In addition, modulation of the endogenous T-cell function during IM therapy was studied.

Methods

We evaluated Th1 (gamma interferon (IFN-γ)), Th2 (interleukin (IL-4)) and tumor necrosis factor (TNF)-α cytokine synthesis by activated T-cell subsets in 20 patients with newly diagnosed CML in chronic phase (CP CML) using flow cytometry before and during IM therapy compared to patients with IM resistance (IM Res) and healthy donors.

Results

Patients with optimal response (CML OR) to IM demonstrated a lower pre-treatment Th1 cytokine compared to that of healthy donors, and a higher percentage of Th2 and TNF-α producing T cells compared to that of healthy donors, non-optimal responders (CML nOR) and those with IM Res. A shift from Th2 profile to Th1 profile and initial decline of TNF-α producing T cells was detected early during therapy in optimal responders which was coinciding with complete hematological remission with a significant increase in the percentages of CD4+ve/IFN-γ+ve cells (P = 0.01) and a significant drop of in CD8+ve/IL-4+ve T cells (P = 0.04).

Conclusion

We believe that pre-treatment levels of IL-4 and/or TNF-α may have a role in identifying CP CML patients who may respond to IM therapy; however, further investigation is needed.