| Despit of comprehensive treatments with primary surgery integrated with chemiotherapy or radiotherapy, the survival rate of the patients with Oral Squamous Cell Carcinoma(OSCC) has not been improved evidently, especially advanced OSCC. Dendritic cells (DCs), which are uniquely the most potent professional antigens-presenting cells(APCs) with the capacity to activate naive T lymphocytes, are considered to be promising adjuvants for immunity against cancer. The purpose of the studies was to provide some theoretic and experimental evidences for the application of DCs to clinical immunotherapy of OSCC, by elucidating the functional state of DCs in the tissue of OSCC and its regional lymph node (RLN), investigating the in vitro-culturing approach of DCs from peripheral blood monocyte and the technique for preparation of DC vaccine of OSCC, and observing antitumor effect of T lymphocytic responses induced by DC vaccine in vivo and ex vivo.In the studies, OSSC and its RLN were immunohistochemistrically stained to mark the characteristically phenotypical antigens of DCs, with normal mucosa and chronic inflammatory tonsil as control. The expressing state of the antigens was observed. Human peripheral blood monocytes isolated from leukocytes were cultured in complete media with two various cytokine cocktails: GM-CSF+IL-4 /or +TNF-a. Two types of DCs were generated and investigated by morphology, characteristic phenotype and faction of stimulating allogeneic mixed lymphocyte reaction (MLR). The types of DCs were pulsed with Tca8113 cell lysate made by freeze-thawing method so that DC vaccine was prepared. The characteristic phenotype of the DCs was detected by immunocytochemistry. The antitumor effect of Tlymphocytic responses induced by the DC vaccine was assessed by MTT assay. Mature DCs were used as vehicles for the delivery of the tumor antigens after pulsed with freeze-thaw Tca8113 lysates. The T lymphocytes activated by the DCs were infused in BALB/c nude mice in which implanted tumors of Tca8113 had been established. The growth of the tumors was observed. The results showed that the density of CDla+ DCs was significantly lower in OSCC (P< 0.05), and the HLA-DR + rate of DCs in OSCC was not significantly different (P > 0.05), compared with normal mucosa, but CD83 + DCs was not detectable in OSCC. Although the density of CDla+ DCs higher (P< 0.01), the ratio of CD83 "DC/CD la+DC was significantly lower in lymph node (P < 0.05) than tonsil; The density of CDlaT DCs in metastatic lymph node was significantly lower than non-metastatic(P < 0.05). Mature DC were induced by GM-CSF+IL-4+TNF-cx cytokines, with typical dendrite-like morphology, higher expression of CD83+and lower CDla+, and more forceful capacity to stimulate MLR than GM-CSF+IL-4 (P< 0.01). After the pulse of Tca8113 lysates, mature DCs more efficiently induced T lymphocyte-mediated responses against Tca8113 than immature DCs. T lymphocyte activated by DCs vaccine bated the growth of implanted tumor in the nude mice with the tumor-controlled rate of 81.574 %.The results indicated that ? The functional maturation of DCs might be inhibited by the immunosuppressive effect of OSCC. ? The hindrance of DCs' functional maturation could cause the inability of DCs to present antigen in RLNs. (3) DCs can be generated from monocytes in the presence of GM-CSF+IL-4 , TNF-a can promot the DCs mature. ? Immature DCs can mature through ingestion of tumor antigens in vitro. Mature DCs can be loade with tumor antigens, and more powerfully activate T lymphocyte-mediated immune responses against Tca8113 in vitro. ? Mature DCs, after loaded with tumor antigens, can ignite autologous T lymphocytes to perform suppressive function against implanted tumor of Tca8113 in nude mice. |
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