Expression of PD‐L1 on regulatory B cells in patients with acute myeloid leukaemia and its effect on prognosis

Programmed death‐ligand 1 (PD‐L1) is involved in immunosuppression in variety of tumours. Regulatory B cells (Bregs) are critical immune regulatory cells, and it has been demonstrated that the number of regulatory B cells in patients with acute myeloid leukaemia (AML) is much higher than that in healthy donors (HDs), which is linked to a poor prognosis. This study aimed to determine whether increased expression of PD‐L1, including in Bregs, is associated with a worse prognosis in individuals with AML. The proportion of Bregs, PD‐L1 expression in Bregs and PD‐1 expression in T cells were determined using flow cytometry using patient samples from 21 newly diagnosed AML patients at different stages of treatment and 25 HDs. We confirmed PD‐L1 expression in Bregs, and PD‐1 expression in CD3⁺CD4⁺T cells in bone marrow and peripheral blood samples from AML patients was higher than that in samples from HDs. The complete remission (CR) and progression‐free survival (PFS) of Bregs with high PD‐L1 expression were significantly decreased following induction chemotherapy. PD‐L1 expression is indeed increased in Bregs from individuals with AML, and high PD‐L1 expression is related to a poor prognosis.     

Gata4, Tbx5 and Baf60c induce differentiation of adipose tissue-derived mesenchymal stem cells into beating cardiomyocytes

The adipose tissue-derived mesenchymal stem cells (ADMSCs) are extensively utilized in tissue engineering, regenerative medicine and cell therapy. ADMSCs can differentiate into cardiomyocytes, and it has been shown that over-expression of a cocktail of factors can induce ectopic heart formation and program cardiogenesis in ESCs. However, which genes are responsible for differentiation of ADMSCs into beating cardiomyocyte-like cells remains unknown. In this study we have shown that the combination of Gata4, Tbx5 and Baf60c is sufficient for inducing ADMSCs to form cardiomyocytes. It also appears that, while Gata4 and Baf60c are key inducers of myocardial differentiation, Tbx5 is essential for the ability of cardiac cells to contract. These findings provide additional experimental references for myocardial tissue engineering in the emerging field of cell-based therapy of heart diseases.     

Minimally-invasive Technique for Injection into Rat Optic Nerve

The rat optic nerve is a useful model for stem cell regeneration research. Direct injection into the rat optic nerve allows delivery into the central nervous system in a minimally-invasive surgery without bone removal. This technique describes an approach to visualization and direct injection of the optic nerve following minor fascial dissection from the orbital ridge, using a conjunctival traction suture to gently pull the eye down and out. Representative examples of an injected optic nerve show successful injection of dyed beads.     

Vibrio cholerae persistence in aquatic environments and colonization of intestinal cells: involvement of a common adhesion mechanism

Forty-one Tnpho A mutants of Vibrio cholerae O1 classical strain CD81 were analyzed for their ability to interact with chitin particles, Tigriopus fulvus copepods and the Intestine 407 cell line compared to the parent strain. Thirteen mutants were less adhesive than CD81; in particular, T21, T33 and T87 were less adhesive towards all substrates and insensitive to inhibition by N-acetyl glucosamine (GlcNAc). By SDS-PAGE analysis of sarkosyl-insoluble membrane proteins (siMPs) isolated from mutants and parent, it was found that a 53 kDa siMP is missing in T21, T33 and T87 mutants. It is hypothesized that this protein might have the function to mediate adherence to GlcNAc-containing substrates both in the aquatic environment and in human intestine.     

Mass transfer effects on the reaction rate for heterogeneously distributed immobilized yeast cells

Here we examine the efficiency of different immobilized cell gradients applied to immobilized Saccharomyces cerevisiae fermenting glucose to ethanol. We developed a simulation model to fully study the competing effects of mass transfer hindrance and kinetics. It is based on a diffusion-reaction model and can be used to analyze the different cell concentration profiles inside an immobilized gel bead, in terms of effectiveness factors, productivity, and mass flux. The internal diffusion coefficient, which varies with the local cell concentration, as well as the external mass transfer, is taken into account when describing the efficiency. Although the diffusion hindrance is greater at higher cell concentrations, high cell concentration is still advantageous in the present case because the increase in reaction rate outweighs the diffusion hindrance. Thus, high cell concentrations contribute to increased productivity. The influence of the cell concentration gradient on the efficiency of the beads is negligible. Within the range of cell profiles studied it has been established that the location of the cells within the bead is of lesser importance. However, a steep cell gradient increases the importance of the external mass transfer.     

Chemo-adoptive immunotherapy of nude mice implanted with human colorectal carcinoma and melanoma cell lines

Summary The antitumor effects of chemotherapy, recombinant human interleukin-2 (IL-2), recombinant human interferon A/D (IFN), allogeneic human lymphokine-activated killer (LAK) cells, and antitumor monoclonal antibody (mAb), administered alone and in various combinations, were tested in athymic nude mice carrying human tumor xenografts. Treatment began 6–18 days after i.v. or i.p. inoculation of colorectal carcinoma or melanoma cell lines, when macroscopic growths were evident. Chemotherapy consisted of two or three courses of 5-fluorouracil (5-FU) or dacarbazine. IL-2 and/or IFN were administered three to five times weekly for 1–3 weeks, usually starting 2–5 days after chemotherapy. Human LAK cells were infused once or twice weekly for 2 or 3 weeks concurrently with IL-2. In some experiments, murine anticolorectal carcinoma mAb (SF25) was administered. In both tumor systems, chemotherapy alone or immunotherapy alone (IL-2, IL-2 + LAK cells, IFN, IL-2 + IFN ± LAK cells) had little or no therapeutic effects. Additive effects were obtained by combining chemotherapy with IL-2 and LAK cells or with IL-2 and IFN. In the majority of the experiments, the most effective combination was chemotherapy + IL-2 + IFN + LAK cells. Treatment with mAb was beneficial in the colorectal carcinoma system when combined with 5-FU + IL-2 or 5-FU + IL-2 + IFN. Homing experiments with radiolabeled human and mouse LAK cells injected i.v. showed increased early accumulation in the liver and lungs, whereas freshly explanted mouse splenocytes localized mostly in the spleen and liver. The tissue distribution pattern of human LAK cells was similar in normal and tumor-bearing mice (with lung metastases). These findings suggest that combination of chemotherapy with cytokines and LAK cells can be partially effective for advanced solid human tumors even in the absence of the host's T-cell immune response. Preliminary experiments showed that tumor-specific, anti-melanoma T-cell clones were effective in local (s.c.) tumor growth inhibition (Winn assay) following coinjection with the autologous tumor cells.     

解脲脲原体诱导脐静脉血管内皮细胞凋亡的研究

目的通过探讨解脲脲原体(Ureaplasma urealyticum,UU)诱导人脐静脉内皮细胞(human umbilicalvein endothelial cells;HUVEC)凋亡的情况,揭示妊娠期间UU垂直传播影响胚胎发育的可能机制。方法不同剂量血清4型UU标准菌株刺激体外培养的HUVEC,通过Annexin-V.FITC/PI双染流式细胞术和DNA Ladder实验观察细胞凋亡情况。结果对照组细胞凋亡率小于各实验组(P<0.01~0.05),其凋亡率和刺激剂量、时间之间呈现一定的剂量-时间-效应关系(P>0.05)。结论UU可诱导人脐静脉内皮细胞凋亡,提示妊娠期间UU感染可能通过诱导脐静脉内皮细胞凋亡破坏胎盘屏障而影响胚胎发育。