Killer dendritic cells link innate and adaptive immunity against established osteosarcoma in rats.

We have previously reported that a distinct subset of splenic CD4(-) rat dendritic cells (DC) induces a rapid and caspase-independent apoptosis-like cell death in a large number of tumor cells in vitro. The killing activity of these killer DC (KDC) was restricted to their immature state and was immediately followed by their engulfment of the apoptotic target cells, suggesting that these KDC could directly link innate and adaptive immunity to tumors. Here, we addressed this question using a transplantable model of rat osteosarcoma. First, we showed that rat KDC have an MHC II(+)CD103(+)CD11b(+)NKp46(-) phenotype and are therefore distinct from natural killer cells, which are MHC II(-)CD103(-)CD11b(-)NKp46(+). KDC numbers could be specifically and strongly (up to 10-fold) enhanced by Flt3L in vivo. The OSRGa cell line derived from the osteosarcoma tumor was killed and phagocytosed in vitro by both normal and Flt3L-induced splenic KDC. Such tumor antigen-loaded KDC were used to s.c. vaccinate progressive tumor-bearing rats. Vaccination with OSRGa-loaded KDC but not KDC loaded with irrelevant tumor cells (Jurkat) delayed tumor progression or even induced tumor regression. This vaccine effect was not observed in CD8 T cell-depleted animals and protective against tumor rechallenge. These results suggest that KDC possess the intrinsic capability not only to kill and then engulf tumor cells but also to efficiently cross-present tumor cell-derived antigen in vivo and subsequently induce an adaptive antitumor immune response.

Arthroscopic treatment of distal clavicle fractures: a technical note.

This article describes a new technique for the arthroscopic treatment of distal clavicle fractures. This technique requires the use of posterior and anterior standard arthroscopic portals. The base of the coracoid process is exposed through the rotator interval. The ancillary system drill guide is placed at the undersurface of the coracoid process. A small incision is performed above the clavicular body and the corresponding part of the guide is pushed down to the clavicle. A 4-mm hole is drilled through the clavicle and the coracoid process. A double button device is pushed through both the holes. The first button is pushed below the coracoid. The device is tightened and the second button is fixed on top of the clavicular cortical bone, allowing reduction and fixation of the fracture. Four patients treated with this technique were evaluated at 6 months postoperatively. All patients showed bony union and a full recovery of the shoulder function. The technique provides firm fixation of fractures of the distal clavicle.