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d-pinitol has been demonstrated to exert insulin-like and anti-inflammatory effects. However, the effects of the maturation and immunostimulatory functions of dendritic cells (DC) remain to be clearly elucidated. In this study, we have attempted to determine whether d-pinitol regulates surface molecule expression, cytokine production, endocytosis capacity, and underlying signaling pathways in murine bone marrow-derived DC. We also attempted to ascertain whether d-pinitol could influence Th1/Th2 immune response in vivo. The DC used in this study were derived from murine bone marrow cells, and were used as immature or LPS-stimulated mature DC. The DC were then assessed with regard to surface molecule expression, dextran-FITC uptake, cytokine production, capacity to induce T-cell differentiation, and underlying signaling pathways. d-pinitol was shown to significantly inhibit CD80, CD86, MHC class I, and MHC class II expression in the LPS-stimulated mature DC. The DC also evidenced impaired IL-12 expression and IFN-gamma production. The d-pinitol-treated DC were found to be highly efficient in regards to Ag capture via mannose receptor-mediated endocytosis. d-pinitol was also demonstrated to inhibit LPS-induced MAPKs activation and NF-kappaB nuclear translocation. Moreover, the d-pinitol-treated DC manifested impaired induction of Th1 responses, and normal cell-mediated immune responses. These novel findings provide new insight into the immunopharmacological role of d-pinitol in terms of its effects on DC. These findings also broaden current perspectives concerning our understanding of the immunopharmacological functions of d-pinitol, and have ramifications for the development of therapeutic adjuvants for the treatment of DC-related acute and chronic diseases.

Dendritic cells (DCs) are potent antigen presenting cells that are uniquely effective in generating primary immune responses. DCs that are manipulated to present tumor antigens induce antitumor immunity in animal models and preclinical human studies. A myriad of strategies have been developed to load tumor antigen effectively onto DCs. DC-tumor fusion presents a spectrum of tumor-associated antigens to helper T- and cytotoxic T-cell populations in the context of DC-mediated costimulatory signals. In this study, fusion cells (FCs) were generated with MCA-102 fibrosarcoma cells and murine bone marrow-derived myeloid DCs. The FCs coexpressed the DC-derived MHC class II and costimulatory molecules. The FCs also retained the functional properties of DCs and stimulated syngeneic T cell proliferation and interferon-gamma (IFN-gamma) production. Significantly, the results show that syngeneic T cells are primed by FCs to induce MHC class I-dependent lysis of MCA-102 fibrosarcoma. These findings indicate that fusions of tumor cells and DCs activate T-cell responses against syngeneic tumors.

Immunization of dendritic cells (DC) pulsed with tumor antigen can activate tumor-specific cytotoxic T lymphocytes (CTL) which are responsible for protection from tumor challenge and regression of established metastatic tumor. It has been hypothesized that tumor lysate contains factors that may modulate DC maturation. In this study, we examined whether the uptake of tumor lysate (MCA-102 fibrosarcoma) could modulate DC phenotypes in vitro and whether the administration in vivo of tumor lysate-pulsed DC (TP-DC) could elicit efficient tumor specific immune responses followed by a regression of established tumor burdens. It was investigated the uptake of tumor lysate by DC by means of flow cytometry and fluorescent microscope. Murine bone marrow-derived DC efficiently phagocytosed tumor lysate and after the uptake, the phenotype of TP-DC was surprisingly comparable to unpulsed-DC (UP-DC), exhibiting lower levels of CD80 (51%), CD86 (43%), and MHC class II (59%). Also, TP-DC did not enhance secretion of IL-12p70 (UP- vs. TP; 54.5+/-6.4 vs. 50.5+/-4.8 pg/ml, respectively), contrary to those activated with LPS (113.6+/-16.8 pg/ml). However, TP-DC vaccination in vivo increased the IFN-gamma production from splenocytes higher than that of UP-DC (TP- vs. UP-DC; 41029+/-1523 vs. 4752+/-590 pg/ml, respectively). Furthermore, the administration of TP-DC enhanced specific T cell responses against MCA-102 fibrosarcoma. These results demonstrate that augmentation of DC phenotype and function in vitro is not necessarily a prerequisite for TP-DC vaccination to successfully promote anti-tumor immunity in vivo.

Among 145 patients that underwent prosthetic reconstruction between 1985 and 1998, infection developed in 18. Osteosarcoma was the most common primary tumour, and staphylococci were the major pathogenic organisms. Infections were controlled in five patients with debridement only and in two patients with a two-stage revision. Arthrodeses were performed in three and amputations in two. In six patients, infection was suppressed with antibiotics but not cured. Pulmonary metastasis developed in four of ten patients in whom chemotherapy was delayed or interrupted. Infection controls were poor in cases of delayed debridement over 2 weeks, in cementless fixation of implant, and soft tissue defects (P