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.

Activation of granulocytes by direct interaction with dendritic cells.

Granulocytes from human peripheral blood were co-cultured with conventional dendritic cells (cDC) or plasmacytoid DCs (pDC) to examine the effects of DCs on the activation or function of granulocytes. After co-culture of granulocytes with DCs, expression of the activation markers of granulocytes (CD63 and CD64) was up-regulated, and increased expression of CD50, the activation marker and ligand for CD209 (DC-SIGN) was also observed. The interaction of granulocytes with DCs was visualized as the cluster where DCs, especially cDCs, were surrounded by granulocytes to form a 'rosette'. After co-culture of granulocytes with cDCs, the secretion of elastase from granulocytes was enhanced significantly when examined cytohistochemically and by enzyme-linked immunosorbent assay. An increase in myeloperoxidase (another activation index of granulocytes) was also observed after co-culture with DCs. These findings suggest the functional and phenotypical activation of granulocytes by interaction with DCs. Furthermore, we examined the involvement of adhesion molecules in the granulocyte-DC interaction, and found that CD209 participates to some extent in this interaction.

Synergistic effects of injection of bone marrow cells into both portal vein and bone marrow on tolerance induction in transplantation of allogeneic pancreatic islets.

We have established a new method for allogeneic pancreatic islet (PI) transplantation: relatively low doses of irradiation followed by simultaneous transplantation of PIs and bone marrow cells (BMCs) via the portal vein (PV). In the present study, we have compared this method with intra-bone marrow (IBM)-bone marrow transplantation (BMT), and with a combination of both methods. Streptozotocin (STZ)-induced diabetic-recipient rats, Fischer 344 (F344, RT1A(l), RT1B(l)), were irradiated 1 day before transplantation. PIs of Brown Norway rats (BN, RT1A(n), RT1B(n)) were transplanted into the liver of the diabetic F344 rats via the PV. BMCs from BN rats were injected into the recipients' bone marrow (IBM), PV or intravenously (IV) or by a simultaneous combination of PV plus IBM (PV+IBM). We compared graft survival among the groups of '9 Gy+IBM'(10/10 accepted), '9 Gy+PV'(7/10 accepted), '9 Gy+IV'(0/7 accepted), '9 Gy+PV+IBM'(8/8 accepted), '8.5 Gy+IBM'(4/9 accepted), '8.5 Gy+PV'(0/7 accepted), '8.5 Gy+IV'(0/7 accepted), '8.5 Gy+PV+IBM'(9/12 accepted), '8 Gy+IBM'(2/10 accepted) and '8 Gy+PV+IBM'(2/8 accepted). As we reported previously, PV-BMT is more effective in inducing the acceptance of allogeneic PIs than IV-BMT. However, IBM-BMT requires less pretreatment than PV-BMT. (PV+IBM)-BMT was found to be the most effective in inducing the acceptance of allogeneic PIs. These results suggest that allogeneic PI-transplantation in conjunction with (PV+IBM)-BMT could become a viable strategy.