MG132 Induced Apoptosis Pathway in HL-60 Cells and Impact of Allogeneic Mixed Lymphocyte Reaction

Objective： To investigate the proteasome inhibitor MG132-induced apoptosis pathway in HL-60 cells and the role of allogeneic mixed lymphocyte reaction. Methods： Cell apoptosis was analyzed by flow cytometry. The expressions of p21 protein, p27 protein and p53 protein in HL-60 ceils treated with MG132 were measured by Western blot. The proliferation of, peripheral blood mononuclear cells （PBMNCs） after treatment with 75 Gy irradiated HL-60 cells treated with MG132 was measured with CCK-8. Results： High-dose MG132 induced apoptosis in HL-60 cells. No significant change was observed in MG132-induced apoptosis after inhibiting caspase-8 and caspase-9 pathway. The expressions of p21 protein and p27 protein increased in MG132-induced apoptosis. HL-60 cells treated with low-dose MG132 improved the proliferation of PBMNCs from healthy volunteers. Conclusion： High-dose MG132 induced apoptosis and directly killed HL-60 ceils. MG132 induced apoptosis in a caspase-8- and caspase-9-independent pathway, p21 protein and p27 protein were involved in MG132-induced apoptosis in HL-60 cells. HL-60 cells treated with Low-dose MG132 improved the effect of promoting the proliferation of PBMNCs from healthy volunteers.

IMPAIRED AUTOLOGOUS MIXED LYMPHOCYTE REACTION CORRELATED WITH DECREASED EXPRESSION OF HLA-Ⅱ ANTIGENS ON MONOCYTES IN PATIENTS WITH MYELOID LEUKEMIA

The proliferative response of T-cells to autolo-gous non-T-cells is referred to as the autologous mixed lymphocyte reaction (AMLR). Recent studies have suggested that AMLR represents a mechanism of immune regulation in vivo. We investigated AMLR in patients with acute- and chronic myeloid leukemia (AML and CML). AMLR was found to be significantly depressed (P<0.001) in AML patients (n=17, cpm=532±95) and CML patients (n=13, cpm=688±99) when compared with that of their healthy HLA-identical siblings serving as controls (n=17, cpm=4152±619 and n=13 cpm=4086±421, respectively). In order to understand the cellular basis of the defective AMLR in patients with AML end CML, we performed mitogen-treated T-cell cultures analysis of T-cell subsets and HLA-Ⅱ antigen detection on monocytes. The results indicated that the defect of AMLR in patients resided at the stimulator monocyte level rather than at the responder T-cell level. Enumeration of monocytes reactive with monoclonal antibody Tu22, which recognizes determinants of HLA-DQ, demonstrated that ML patients had a significantly decreased (P<0.091) number of circulating Tu22+ monocytes when compared with normal controls. These studies suggest that a deficiency of HLA-DQ+ monocytes contributes to the depression of AMLR in ML and possibly underlies the abnormalities of immune response present in this disease.

Mixed lymphocyte reaction induced by multiple alloantigens and the role for IL-10 in proliferation inhibition

The frequency of T cells that can respond to alloantigens is unusually high.It remains unclear how T cells would respond when stimulated by multiple major histocompatibility complex(MHC)disparate alloantigens in the same cultures.In this report,we examined potential interactions of T cell clones that were stimulated simultaneously by two sets of complete MHC disparate alloantigens using mixed lymphocyte reaction(MLR).In this assay,we observed that proliferation of B6 lymphocytes(H-2b)stimulated by both BALB/c(H-2d)and C_(3)H(H-2k)allogeneic cells was not increased but rather reduced as compared to B6 cells stimulated with either BALB/c or C_(3)H allogeneic cells.Interestingly,interleukin(IL)-10 expressions at both protein level and mRNA level was signifi cantly increased in cultures stimulated with the two MHC alloantigens,while IL-2,tumor necrosis factor(TNF)-α,transforming growth factor(TGF)-β1 production did not show any differences.In addition,Foxp_(3) mRNA expression was comparable amongst all groups.In conclusion,we observed an inhibitory effect in T cell proliferation in response to multiple MHC mismatched alloantigens in MLR,and this effect might be associated with the upregulation of IL-10 expression.

Clinical Grade of Gerneration of Dendritic Cells for Immunotherapy

In order to develop a protocol for clinical grade generation of dendritic cells (DCs) for cancer immumotherapy, aphereses were performed with the continuous flow cell separator and mate- rials were derived from 10 leukemia patients that had achieved complete remission. Peripheral blood monocytes were cultured in vitro with GM-CSF, IL-4 for 6 days, then TNF-α (the TNF-α group) or TNF-α, IL-1β, IL-6, PGE2 (the cytokine mixture group) were added to promote maturation. Cell number was counted by hematology analyzer, and phenotype study (CD1a, CD14, CD83) was carried out by flow cytometry, and the function of DCs was examined by mixed lymphocyte reaction. The results showed that (0.70±0.13)×107/mL (the TNF-α group) and (0.79±0.04)×107/mL (the cytokine mixture group) DCs were generated respectively in peripheral blood obtained by leucapheresis. The phenotypes were as follows: CD1a+ (74.65±4.45)%, CD83+ (39.50±4.16)%, CD14+ (2.90±1.76)% in TNF-α group, and CD1a+ (81.86±5.87)%, CD83+ (81.65±6.36)%, CD14+ (2.46±1.68)% in the cyto- kine mixture group. It was concluded that leucapheresis may be a feasible way to provide large num- ber of peripheral blood monocytes for DC generation, and combined administration of TNF-α, IL-1β, IL-6, and PGE2 may greatly promote maturity.