The combination method using magnetic beads and a magnet helps sustain the number of donor BM cells after intra-BM injection, resulting in rapid hematopoietic recovery.

We have developed a new BMT method, intra-BM-BMT (IBM-BMT), in which donor BM cells (BMCs) are directly injected into the recipient's BM, resulting in a rapid recovery of donor hematopoiesis and a reduction in the severity of GVHD. In the present experiment, we attempted to retain the number of injected BMCs using magnetic beads and a magnet. The BMCs of donor mice were conjugated with magnetic beads, and these cells were then injected into the BM of recipient mice with a magnet (magnet-IBM group) and compared with conventional IBM-BMT without a magnet (IBM group). A significantly higher number of transplanted cells were detected in the injected BM in the magnet-IBM group. We next carried out day-12 colony-forming units of spleen (CFU-S) assays to examine the early stage of hematopoiesis of the injected host hematopoietic stem cells after IBM-BMT. The spleens of mice in the magnet-IBM group showed considerably higher CFU-S counts than those in the IBM group. Excellent reconstitution of donor hematopoietic cells in the magnet-IBM group was observed 1 month after IBM-BMT. These results suggest that the IBM-BMT using the combination of magnetic beads and a magnet is superior to the conventional IBM-BMT.

High mortality rate of (NZW x BXSB)F1 mice induced by administration of lipopolysaccharide attributes to high production of tumour necrosis factor-alpha by increased numbers of dendritic cells.

(NZW x BXSB)F1 mice (W/BF1 mice) have been reported to be a type of autoimmune-prone mice, showing symptoms of proteinuria, anti-DNA antibodies and anti-platelet antibodies. In this paper, we report that W/BF1 mice show hyperproduction of tumour necrosis factor (TNF)-alpha, responding to lipopolysaccharide (LPS) in comparison with normal mice, resulting in induction of death. In normal mice, monocytes/macrophages (Mo/MØ) are the main producer of TNF-alpha, while both Mo/MØ and dendritic cells (DCs) produce TNF-alpha in W/BF1 mice. Because the number of DCs is higher in W/BF1 mice, the main producers of TNF-alpha in W/BF1 mice are thought to be DCs. Moreover, administration of anti-TNF-alpha antibodies rescued the W/BF1 mice from death induced by LPS, suggesting that TNF-alpha is crucial for the effect of LPS. Although there is no significant difference in the expression of Toll-like receptor-4 (TLR-4) on DCs between B6 and W/BF1 mice, nuclear factor kappa b activity of DCs from W/BF1 mice is augmented under stimulation of LPS in comparison with that of normal mice. These results suggest that the signal transduction from TLR-4 is augmented in W/BF1 mice in comparison with normal mice, resulting in the hyperproduction of TNF-alpha and reduced survival rate. The results also suggest that not only the quantity of endotoxin, but also the host conditions, the facility to translate signal from TLR, and so on, could reflect the degree of bacterial infections and prognosis.

Intra-bone marrow injection of dendritic cells for treatment of malignant tumor in mice.

It has recently been reported that antigen presentation from dendritic cells (DCs) to T cells occurs in the bone marrow, and that not only tumor antigen-pulsed DCs but also unpulsed DCs have some anti-tumor effects, resulting from the induction of anti-tumor immunity. In this paper, we examined whether dendritic cells induced from bone marrow cells (BMCs) have the capacity to suppress tumor growth and, if so, which route (intravenous, subcutaneous, or intra-bone marrow injection) is best. BALB/c mice that had been subcutaneously inoculated with Meth A (a murine fibrosarcoma cell line) were injected with BMC-derived DCs via the above three routes. We also examined the tumor suppressive effects of DCs from tumor-bearing mice. Although IBM injection showed similar effects to subcutaneous injection on the suppression of tumor growth, intravenous injection was less effective. It seems likely that the IBM injection of DCs activates tumor-specific T cells, resulting in the suppression of the tumor growth. DCs derived from tumor-bearing mice had some effects on the suppression of tumor growth but they were less effective than DCs from untreated mice.