重组E.coli. LLO/OVA明显增强小鼠CD11c细胞活性及抗肿瘤免疫

目的 探讨重组E.coli. LLO/OVA 诱导C57BL/6小鼠机体免疫的途径,观察其免疫后小鼠机体抑制B16-OVA黑色素瘤的效果.方法 磁珠分离E.coli. LLO/OVA及E.coli. OVA免疫后小鼠脾脏CD11c、CD4 和CD8 T细胞并检测CD11c细胞诱导同源CD4 和CD8 T增殖水平和细胞因子分泌程度;流式细胞检测小鼠脾脏内肿瘤抗原OVA257-264 SIINFEKL特异的细胞毒T细胞含量.比较两种E.coli. 免疫后,恶性黑色素瘤B16-OVA在小鼠肺内形成瘤结节的数量.结果 与E.coli. OVA相比, E.coli. LLO/OVA免疫后小鼠脾脏CD11c细胞诱导同源CD4 T细胞增殖作用增强、IL-2分泌增高;同时诱导CD8 T细胞增殖和IFN-γ分泌的作用也明显增强;OVA257-264 SIINFEKL特异的CD8 T细胞含量也明显增高;小鼠肺内形成B16-OVA瘤结节平均数明显减少. 结论 E.coli. LLO/OVA有效地诱导小鼠CD11c细胞活化,增强其对CD4 T细胞增殖和IL-2分泌以及对CD8 T细胞增殖、IFN-γ分泌的作用,诱导了更多的OVA特异的CD8 T细胞,使机体产生了更强的抗肿瘤免疫.     

钩吻素子对免疫磁珠分离纯化的小鼠CD4+T细胞体外增殖的影响

目的 探讨小鼠脾脏CD4⁺T细胞的分离方法,观察钩吻素子(Kou)对小鼠脾脏CD4⁺T细胞体外增殖的影响.方法 以免疫磁珠分选法从小鼠脾脏细胞中分离CD4⁺T细胞,流式细胞术检测所得细胞的纯度,台盼蓝法检测细胞活力.将10～20μg/ml Kou分别作用于经刀豆蛋白A或植物血凝素刺激的小鼠T淋巴细胞,四唑盐比色法检测细胞增殖情况,用酶联免疫法检测细胞上清中IL-2的含量.结果 经过流式细胞仪测定分离后的小鼠脾脏CD4⁺T细胞纯度达到90.%±5.8%:0.2%台盼兰染色细胞活力为94.9%±.6%;增殖试验表明分离后未加Kou的CD4⁺T细胞对刀豆蛋白A、植物血凝素的刺激保持了良好的增殖能力,当浓度范围为20～20μg/ml时,Kou均能抑制淋巴细胞的增殖(P<0.05),且表现出一定的剂量相关性;不同浓度的Kou(20、100、200μgm1)作用后,CD4⁺T细胞培养上清中的IL-2水平明显低于对照组(P<0.05).结论 免疫磁珠阴性分选法操作简单、快速,可获得较高纯化率、有活性的CD4⁺T细胞;Kou明显抑制小鼠CD4⁺T淋巴细胞增殖反应,此抑制作用可能与Kou抑制小鼠CD4⁺T细胞IL-2的分泌及免疫抑制作用相关.     

On chip cell separator using magnetic bead-based enrichment and depletion of various surface markers

This paper presents an on-chip magnetic cell sorting system for the sorting of cells based on a variety of surface markers. A polymer lab on a chip integrated with an electroplated array of Ni/Fe permalloy has been designed, fabricated, and characterized for the separation of cell substitutes at a variety of flow rates and incubation times. The system sequentially labels cell substitutes with magnetic beads and sorts them, repeating this process to sort for a variety of surface markers. Flow rates and incubation times were varied to characterize the system and produce the best combination of high specific capture and low nonspecific capture. The separation system developed on polymer is selective and efficient while being low cost, portable, and fabricated in a modular structure that can be integrated with other cell handling processes.     

Accurate spike sorting for multi‐unit recordings

Simultaneous recordings with multi‐channel electrodes are widely used for studying how multiple neurons are recruited for information processing. The recorded signals contain the spike events of a number of adjacent or distant neurons and must be sorted correctly into spike trains of individual neurons. Several mathematical methods have been proposed for spike sorting but the process is difficult in practice, as extracellularly recorded signals are corrupted by biological noise. Moreover, spike sorting is often time‐consuming, as it usually requires corrections by human operators. Methods are needed to obtain reliable spike clusters without heavy manual operation. Here, we introduce several methods of spike sorting and compare the accuracy and robustness of their performance by using publicized data of simultaneous extracellular and intracellular recordings of neuronal activity. The best and excellent performance was obtained when a newly proposed filter for spike detection was combined with the wavelet transform and variational Bayes for a finite mixture of Student’s t‐distributions, namely, robust variational Bayes. Wavelet transform extracts features that are characteristic of the detected spike waveforms and the robust variational Bayes categorizes the extracted features into clusters corresponding to spikes of the individual neurons. The use of Student’s t‐distributions makes this categorization robust against noisy data points. Some other new methods also exhibited reasonably good performance. We implemented all of the proposed methods in a C++ code named ‘EToS’ (Efficient Technology of Spike sorting), which is freely available on the Internet.     

Preserved IFN-alpha production of circulating Valpha24 NKT cells in primary lung cancer patients

Human Valpha24 NKT cells bearing an invariant Valpha24JalphaQ antigen receptor, the counterpart of murine Valpha14 NKT cells, are activated by a specific ligand, alpha-GalCer, in a CD1d-dependent manner. Here, we demonstrate decreased numbers of circulating Valpha24 NKT cells in patients with primary lung cancer compared to healthy volunteers. However, Valpha24 NKT cells and DCs from lung cancer patients were functionally normal, even in the presence of tumor. Furthermore, levels of Valpha24 NKT cells in surgically resected lung tissue appeared to be equivalent to those of Valpha14 NKT cells in the mouse lung. Levels of Valpha24 NKT cells in the tumor tissue itself were increased about 2.5 times. Administration of alpha-GalCer-pulsed DCs expanded Valpha14 NKT cells in the lung more than 10 times, and the increased levels were sustained for 1 week. This may explain the previous finding that alpha-GalCer-pulsed DCs exerted strong antitumor activity in mouse lung tumor metastatic models. The potential use of alpha-GalCer-pulsed DCs for immunotherapy aimed at activating endogenous Valpha24 NKT cells in the lung of cancer patients is discussed.     

Sex Selection: Laissez Faire or Family Balancing?

In a recent comment on the HFEAs public consultation on sex selection, Soren Holm claimed that proponents of family balancing are committed to embrace a laissez faire approach. Given that arguments in support of sex selection for family balancing also support sex selection for other social reasons, advocates of family balancing, he asserts, are simply inconsistent when calling for a limit on access to sex selection. In this paper, I argue that proponents of family balancing are in no way inconsistent. Provided their advocacy of family balancing is aimed at preventing a severe distortion of the natural sex ratio, they are entirely justified in insisting on restrictions to sex selection. The real question is whether a concern for the sex ratio does indeed call for a limit on sex selection. Based on a recent survey on gender preferences and data from several Gender Clinics, I argue that a restriction on sex selection to family balancing is unwarranted. In the absence of any evidence for a pending sex ratio distortion, we are actually required to adopt a laissez faire approach to sex selection.     

Enzymatically modified low-density lipoprotein upregulates CD36 in low-differentiated monocytic cells in a peroxisome proliferator-activated receptor-gamma-dependent way

Peroxisome proliferator-activated receptor-gamma (PPARgamma) has been suggested to upregulate CD36. Since free oxidized polyunsaturated fatty acids are PPARgamma ligands, we studied the effects of LDL modified by the simultaneous action of sPLA2 and 15-lipoxygenase (15LO) on CD36 expression and PPARgamma activation in monocytic cells. Exposure of MM6 cells, which do not express CD36 or other scavenger receptors, to such enzymatically modified LDL (enzLDL) resulted in upregulation of CD36 surface protein and mRNA expression. Similar effects were observed with free 13-hydroperoxyoctadecadienoic acid but not its esterified counterpart. Less pronounced effects were observed with LDL modified by 15LO alone. Upregulation of CD36 was inversely correlated to the state of cell differentiation, as showed by lower response to enzLDL of the scavenger receptor-expressing MM6-sr and THP1 cells. Importantly, LDL modified by sPLA2 and 15LO did not efficiently induce upregulation CD36 in PPARgamma-deficient macrophage-differentiated embryonic stem cells confirming a role of PPARgamma in CD36 expression in cells stimulated with enzLDL. Our data show that LDL modified with physiologically relevant enzymes stimulates CD36 expression in non-differentiated monocytes and that this process involves PPARgamma activation. These effects of enzLDL can be considered pro-atherogenic in the context of early atherosclerosis.