PACAP up-regulates the expression of apolipoprotein D in 3T3-L1 adipocytes. DRG/3T3-L1 co-cultures study

The existence of a cross-talk between nerves and fatty tissue is increasingly recognized. Using co-cultures of dorsal root ganglion (DRG)-derived cells and 3T3-L1 adipocytes, we have previously shown that the presence of fat cells enhances neurite outgrowth and number of synapses. Vice versa, neural cells induced expression of neurotrophic adipokines apolipoprotein D and E (ApoD, ApoE) and angiopoietin-1 (Ang-1) by adipocytes. Here, we tested whether pituitary adenylate cyclase-activating peptide (PACAP), which is released by sensory fibres and causes Ca(2+) influx into fat cells, is involved in ApoD induction. Using 3T3-L1 cell cultures, we found that PACAP at a dose of 1 nM up-regulated the expression of ApoD protein and mRNA approx. 2.5 fold. This effect was driven by ERK1/2 acting upon PAC1/VPAC2 receptors. In turn, PACAP-treated 3T3-L1 adipocytes in co-cultures with DRG cells enhanced neurite ramification of neurofilament 200 (NF200)-positive neurons (measured using fluorescence microscopy) and neurofilament 68 protein levels (measured using Western blot analysis). This effect could be blocked using the PAC1/VPAC2 antagonist PACAP(6-38). Scanning cytometry revealed PACAP/ApoD induced low density lipoprotein receptors (LDLR) and ApoE receptor 2 (apoER2) in NF200-positive cells. Thus, a bidirectional loop seems to exist regulating the innervation of fatty tissues: PACAP released from sensory fibres might stimulate fat cells to synthesize neurotrophic adipokines, which, in turn, support peripheral innervation.     

小鼠IL-1α多克隆抗体的制备及应用

目的:构建小鼠白细胞介素-1α原核表达载体,表达并纯化IL-1α蛋白,制备兔抗鼠IL-1α多克隆抗体,并对抗体特性进行初步的鉴定。方法:利用RT-PCR技术,从BALB/c小鼠脾脏cDNA中扩增出IL-1α的全长基因,酶切后连接至pET32a(+)原核表达载体,重组载体测序正确后转化至BL21(DE3)大肠杆菌。利用蛋白质原核表达自动诱导方案成功表达重组蛋白。重组蛋白经电洗脱纯化后用以免疫新西兰大白兔,获得了抗小鼠IL-1α的多克隆抗体,ELISA检测抗体效价。Western blot和流式细胞术(FCM)检测抗血清的特异性。结果:成功构建了重组表达载体pET32a(+)-IL-1α,表达的重组蛋白纯化后免疫新西兰大白兔,得到的多克隆抗体ELISA显示抗体效价可达1∶25 600。Western blot和FCM分析该抗体能特异性结合IL-1α。结论:利用重组的IL-1α蛋白成功制备了高效价、高特异性的兔抗IL-1α抗体,为进一步研究IL-1α的生物学功能奠定了基础。     

Jα33基因工程蛋白与多克隆抗体的制备及初步应用

为了获得同时识别人类和小鼠MAIT细胞的特异性抗体,我们制备了MAIT细胞TCRα链Jα33融合蛋白及其抗体,为MAIT细胞在炎症性肠道疾病(IBD)中作用的研究提供有利的工具。用Jα33的全长序列为引物经PCR扩增Jα33串联体,扩增的串联体片段连接进入T载体,阳性克隆转入pGEX-4T-1表达载体中原核表达GST-Jα33融合蛋白,纯化后的融合蛋白免疫新西兰大白兔制备anti-Jα33多克隆抗体。并分别用Western blot和RT-PCR检测IBD模型小鼠MAIT细胞Jα33的表达。成功获得分子量约为38 kD的融合蛋白,免疫大白兔后得到抗Jα33的多克隆抗体,Western blot结果显示Jα33多克隆抗体能检测到人外周血单个核淋巴细胞表面Jα33的表达,而HeLa中则无Jα33的表达;MAIT细胞Jα33在IBD小鼠肠组织中表达量明显低于正常对照。成功制备了能同时识别人类和小鼠MAIT细胞Jα33的多克隆抗体,为研究MAIT细胞的定位和功能开启了方便之门。     

抗NKG2D多克隆抗体抑制NK和LAK细胞细胞毒效应的研究

目的 :分析抗NKG2D多克隆抗体 ( pAb)对NK和LAK细胞毒作用的影响。方法 :应用密度梯度离心法分离外周血单个核细胞 (PBMC) ,经 10mg/LPHA和 1× 10 6U/LrhIL 2诱导LAK细胞产生 ,再应用流式细胞术 (FCM)分选NK细胞并进行表型检测。加入抗NKG2DpAb封闭NK和LAK细胞表面的NKG2D分子后 ,用MTT比色法检测其细胞毒效应。结果 :经FCM分析证实 ,获得高纯度、高活性的NK细胞。抗NKG2DpAb能显著抑制NK和LAK细胞对K5 6 2、HepG2细胞的细胞毒效应。NK细胞对两种靶细胞的细胞毒效应分别下降了 82 .9%和 75 .6 % ;LAK细胞对两种靶细胞的细胞毒效应分别下降了 5 2 .8%和 5 0 .2 %。但抗NKG2DpAb不能显著抑制两种效应细胞对人鼻咽癌细胞系CNE的细胞毒效应。结论 :抗NKG2DpAb可通过封闭NK和LAK细胞表面的NKG2D分子 ,抑制其对肿瘤细胞的细胞毒效应     

Surface expression of a glycolytic enzyme, alpha-enolase, recognized by autoantibodies in connective tissue disorders

In systemic autoimmune diseases, autoantibodies specific for alpha-enolase are detected more frequently in patients with active renal involvement. To analyze the properties of anti-alpha-enolase antibodies and the distribution of the enzyme in the cell, mouse monoclonal and polyclonal antibodies were obtained from mice immunized with a glutathione-S-transferase-alpha-enolase fusion protein. Anti-alpha-enolase antibodies were purified from patient sera on enolase from human kidney. Using these antibodies, the distribution of alpha-enolase in the cell was analyzed in subcellular fractions and in the cell membrane by flow cytometry and immunoprecipitation. Plasminogen binding was studied by an immunoenzymatic assay. We observed that alpha-enolase was present in the cytosol and membrane fractions obtained from kidney and U937 cells. By flow cytometry, mouse polyclonal anti-enolase antibodies, one monoclonal and 7/9 human anti-enolase antibodies bound the membrane of U937 cells. One monoclonal antibody and mouse polyclonal anti-enolase antibodies immunoprecipitated a 48-kDa molecule from surface-labeled U937 cells and this molecule was recognized by rabbit anti-enolase antibodies. Both immunization-induced antibodies and 7/9 autoantibodies from patient sera inhibited the binding of plasminogen to alpha-enolase. The results show that alpha-enolase, an autoantigen in connective tissue diseases, is a cytoplasmic enzyme which is also expressed on the cell membrane, with which it is strongly associated. Anti-alpha-enolase autoantibodies isolated from patient sera recognize the membrane-associated form of the enzyme and/or interfere with its receptor function, thus inhibiting the binding of plasminogen. Autoantibodies specific for alpha-enolase could play a pathogenic role, either by a cytopathic effect or by interfering with membrane fibrinolytic activity.     

Pituitary adenylate cyclase activating polypeptide: an important vascular regulator in human skin in vivo

Pituitary adenylate cyclase-activating peptide (PACAP) is an important neuropeptide and immunomodulator in various tissues. Although this peptide and its receptors (ie, VPAC1R, VPAC2R, and PAC1R) are expressed in human skin, their biological roles are unknown. Therefore, we tested whether PACAP regulates vascular responses in human skin in vivo. When injected intravenously, PACAP induced a significant, concentration-dependent vascular response (ie, flush, erythema, edema) and mediated a significant and concentration-dependent increase in intrarectal body temperature that peaked at 2.7°C. Topical application of PACAP induced marked concentration-dependent edema. Immunohistochemistry revealed a close association of PACAP-immunoreactive nerve fibers with mast cells and dermal blood vessels. VPAC1R was expressed by dermal endothelial cells, CD4+ and CD8+ T cells, mast cells, and keratinocytes, whereas VPAC2R was expressed only in keratinocytes. VPAC1R protein and mRNA were also detected in human dermal microvascular endothelial cells. The PACAP-induced change in cAMP production in these cells demonstrated VPAC1R to be functional. PACAP treatment of organ-cultured human skin strongly increased the number of CD31+ vessel cross-sections. Taken together, these results suggest that PACAP directly induces vascular responses that may be associated with neurogenic inflammation, indicating for the first time that PACAP may be a crucial vascular regulator in human skin in vivo. Antagonists to PACAP function may be beneficial for the treatment of inflammatory skin diseases with a neurogenic component.     

Clusterin抗原的表达、抗体制备及其初步鉴定

目的:制备Clusterin(CLU)多克隆和单克隆抗体(mAb),并进行特性鉴定.方法:以成人肝cDNA表达文库为模板,构建重组表达质粒pGEX-4T-1-CLU和PET-32a-CLU.GST-CLU融合蛋白在大肠杆菌中表达,被作为免疫原制备兔多抗和鼠mAb.采用ELISA法和Western blot鉴定抗CLU抗血清在重组蛋白和天然蛋白中的特异性.采用Western blot,间接免疫荧光,免疫组化鉴定mAb的特异性.结果:GST-CLU融合蛋白在相对分子质量(Mr)约54 000处呈现明显表达条带.Western blot鉴定表明,制备的抗CLU兔多克隆抗体可特异地识别成人肝总蛋白中Mr约52 000和58 000的CLU蛋白.获得9株可稳定分泌抗CLU的杂交瘤细胞株可识别重组人CLU蛋白,其中有2株可特异性结合HepG2细胞质中的蛋白,4株可特异性结合成人肝脏组织肝细胞质中的蛋白.结论:成功地制备出兔抗人CLU抗血清和9株抗CLU的mAb,为进一步研究CLU在肿瘤中的功能奠定了实验基础.     

Differential-expression and tyrosine-phosphorylation profiles of caveolin isoforms in human T cell leukemia cell lines

Caveolin, the essential structural component of caveolae, serves as a scaffolding protein onto which signaling molecules are assembled, and functions as a negative regulator for signal transduction. Caveolin-1 and -2 are expressed in most cell types, but are not expressed in normal blood cells and cell lines. We previously demonstrated that caveolin-1 is expressed in a panel of human leukemia cell lines that show an activated T cell phenotype. In that study, we detected two caveolin bands by Western blotting using a polyclonal antibody (pAb) reacting with caveolin-1, -2, and -3. We identified caveolin-1alpha by its large molecular weight, but did not discriminatively detect other caveolin families. Since anti-caveolin-1 monoclonal antibody (mAb) was reported not to detect caveolin-1 in some cases, here we developed a sensitive method for the discriminative detection of caveolin-1, -2, and -3 by modified Western blotting. Caveolins were solubilized using a two-step procedure and detected by immunoprecipitation with a pAb to caveolins followed by Western blotting with mAbs specific to each caveolin. Using this method we detected caveolin-1beta, -2alpha and -2beta, but not caveolin-3 in the leukemia cell lines. Caveolin-1alpha, which was identified by pAb, was not detected by this method. We show here that caveolin-1alpha and -2alpha, but not caveolin-1beta and -2beta, are tyrosine phosphorylated. This modification is likely to cause the lack of reactivity of caveolin-1alpha to the mAb, and suggests a possible close relationship to cell activation.     

Assay for Recombinant and Native Human Intraacrosomal Antigen SP-10

PROBLEM: To develop a method to measure a recombinant sperm protein, SP-10, during scale up and purification for a contraceptive vaccine formulation. METHOD: A quantitative assay method for the human intraacrosomal protein SP-10 was developed utilizing the format of indirect capture enzyme-linked immunosorbent assay (ELISA). A SP-10 specific monoclonal antibody mAb, MHS-10, was used as the capture antibody. Two recognition reagents, a rabbit polyclonal anti-SP-10 antisera (pAb) and a biotin-labeled mAb, MHS-10, were used as the recognition antibodies, respectively. A SP-10 recombinant fusion protein consisting of 125 SP-10 amino acids linked to glutathione transferase was used as a working SP-10 standard. The coefficient of variance for the assay system using the rabbit pAb was in the range of 0.099 to 0.157, and for the assay system using the biotinylated mAb MHS-10 was in the range of 0.081 to 0.084. RESULTS: Employing biotinylated MHS-10 as the recognition antibody, it was found that the native SP-10 molecule had more than one MHS-10 epitope. The concentration of SP-10 in a pool of human sperm extracts was found to be approximately 1% of the total proteins, assayed by both of the recognition antibody systems. CONCLUSIONS: The assay system described is useful to monitor the yield of recombinant SP-10 during scale-up production of the SP-10 vaccine.     

FILIP-1L 蛋白的原核表达及多克隆抗体制备

目的： 表达、纯化GST-FILIP-1L融合蛋白,制备FILIP-1L多克隆抗体。方法：pGEX-4T3-FILIP-1L重组质粒转化E-coliBL21大肠杆菌,IPTG诱导GST-FILIP-1L融合蛋白表达,Glutathion Sepharse 4B纯化GST-FILIP-1L融合蛋白。将纯化的GST-FILIP-1L融合蛋白免疫新西兰大耳白兔,制备FILIP-1L多克隆抗体,用ELISA方法检测多克隆抗体效价,Western blot检测多克隆抗体与FILIP-1L蛋白、细胞转染FILIP-1L蛋白及细胞FILIP-1L蛋白的结合能力。结果：在大肠杆菌中诱导出高表达的FILIP-1L融合蛋白,经Glutathion Sepharse 4B纯化后免疫新西兰大耳白兔,获得了高效价的抗FILIP-1L多克隆抗体,亲和层析获得纯度较高的多克隆抗体,WB检测显示多克隆抗体能够与FILIP-1L蛋白、293细胞转染FILIP-1L蛋白及肝癌细胞FILIP-1L蛋白结合。结论：成功表达、纯化了GST-FILIP-1L融合蛋白,制备了高效价的抗FILIP-1L多克隆抗体,为研究FILIP-1L蛋白生物学功能提供了有用的实验工具。     

兔抗B16黑素细胞多克隆抗体的制备及对黑素细胞增殖的影响

目的:制备兔抗B16黑素细胞多克隆抗体,研究其对黑素细胞增殖的影响。方法:①用B16黑素细胞颗粒抗原免疫家兔得到兔抗B16黑素细胞多克隆抗体;试管凝集法检测抗血清效价;G蛋白亲和层析纯化抗血清;②SDS-PAGE检测纯化抗体分子量大小;MTT法检测纯化抗体IgG对B16黑素细胞增殖的影响。结果:兔抗B16黑素细胞抗血清效价高达1:1280;亲和层析纯化抗血清获得的免疫球蛋白IgG,经SDS-PAGE电泳显示重链分子量大小约为66.2kD;MTT比色法显示IgG对黑素细胞增殖有抑制作用,与非IgG和未纯化血清差异显著。结论:成功制备并鉴定了高效价的兔抗B16黑素细胞多克隆抗体,纯化后所获得的高纯度IgG,对B16黑素细胞增殖具有抑制作用,为进一步研究此抗体对黑素细胞生长及色素代谢的影响,以及色素减退性疾病白癜风的发病机制奠定了基础。     

Evidence for the involvement of VPAC1 and VPAC2 receptors in pressure-induced vasodilatation in rodents

A transient increase in skin blood flow in response to an innocuous local pressure application, defined as pressure-induced vasodilatation (PIV), delays the occurrence of ischaemia, suggesting a protective feature against applied pressure. The PIV response depends on capsaicin-sensitive nerve fibres and calcitonin gene-related peptide (CGRP) has been shown to be involved. In these fibres, CGRP coexists with pituitary adenylate cyclase-activating polypeptide (PACAP). Three distinct receptors mediate the biological effects of PACAP: VPAC1 and VPAC2 receptors binding with the same affinity for PACAP and vasoactive intestinal peptide and PAC1 receptors showing high selectivity for PACAP. Because the receptors are widely expressed in the nervous system and in the skin, we hypothesized that at least one of them is involved in PIV development. To verify this hypothesis, we used [ d - p -Cl-Phe⁶,Leu¹⁷]-VIP (nonspecific antagonist of VPAC1/VPAC2 receptors), PG 97-269 (antagonist of VPAC1 receptors), PACAP(6–38) (antagonist of VPAC2/PAC1 receptors) and Max.d.4 (antagonist of PAC1 receptors) in anaesthetized rodents. The blockade of VPAC1/VPAC2, VPAC1 or VPAC2/PAC1 receptors eliminated the PIV response, whereas PAC1 blockade had no effect, demonstrating an involvement of VPAC1/VPAC2 receptors in PIV development. Moreover, endothelium-independent and -dependent vasodilator responses were unchanged by the VPAC1/VPAC2 antagonist. Thus, the absence of a PIV response following VPAC1/VPAC2 blockade cannot be explained by any dysfunction of the vascular smooth muscle or endothelial vasodilator capacity. The involvement of VPAC1/VPAC2 receptors in the development of PIV seems to imply a series relationship in which each receptor type (CGRP, VPAC1, VPAC2) is necessary for the full transmission of the response.     

Allergen-specific polyclonal antibodies reduce allergic disease in a mouse model of allergic asthma

BACKGROUND: Recombinant allergen-specific immunoglobulin G (IgG) antibody therapy can reduce allergic asthma symptoms by inhibiting the immunoglobulin E (IgE)-mediated allergic response. This study investigated the effect of intranasally administered allergen-specific monoclonal (mAb) and polyclonal (pAb) antibody on airway inflammation and hyperresponsiveness (AHR) in a mouse model of human asthma. METHODS: Ovalbumin (OVA)-specific IgG2b antibodies were generated by phage display using spleens from OVA-immunized mice, and screening against OVA and finally expressed in CHO cells. Sensitized mice were treated intranasally with either a recombinant anti-OVA mAb (gc32) or a polyclonal preparation comprising seven selected antibodies (including gc32). Control mice received diluent only, OVA only, a control polymeric IgG or dexamethasone. Following challenge with nebulized OVA, investigators assessed airway inflammation by histology and cellular composition of the bronchoalveolar fluid, and methacholine-induced airway hyperresponsiveness (AHR). Serum levels of total and OVA-specific IgE were measured by ELISA. RESULTS: Sensitized mice developed airway inflammation and AHR in response to OVA challenge. Intranasally administered OVA-specific murine polyclonal or monoclonal IgG2b antibodies both reduced OVA-induced lung inflammation. Polyclonal, but not anti-OVA mAb, also reduced AHR and eosinophil influx into the airway lumen. Both anti-OVA antibody preparations reduced levels of specific IgE with no effect on total IgE levels. CONCLUSIONS: Intranasal treatment with allergen-specific pAb reduces pulmonary inflammation and AHR in a mouse model of allergic asthma, but allergen-specific mAb reduces inflammation only. Allergen-specific recombinant pAb offers a potentially valuable therapeutic approach to the management of allergic asthma.     

翻译控制肿瘤蛋白TPT1的原核表达、纯化、抗体制备和初步应用

目的:原核表达并纯化翻译控制蛋白TPT1,免疫日本大耳白兔制备其抗体。方法:构建原核表达质粒pRSE-TA2-TPT1,转化大肠杆菌BL21(DE3),TPT1蛋白经异丙基-β-D-硫代半乳糖苷(IPTG)诱导表达。融合蛋白通过Ni-NTA树脂亲和纯化后免疫兔子制备抗体血清。以间接ELISA法检测抗体效价,Western blot和免疫荧光染色鉴定抗体特异性。结果:在大肠埃希菌中诱导出高水平表达的TPT1融合蛋白,经亲和树脂纯化后免疫大白兔,获得了高特异性的抗TPT1抗血清。结论:成功构建原核表达质粒pRSETA2-TPT1,表达并纯化TPT1蛋白,制备出高滴度、高特异性的多克隆抗体.为进一步研究TPT1在肿瘤等疾病发生、发展过程及治疗中的作用奠定基础。     

Protein A vectorized toxins--II. Preparation and "in vitro" cytotoxic effect of protein A-ricin A chain conjugate on antibody coated human tumour cells

Protein A of Staphylococcus aureus was covalently bound to reduced ricin A chain toxin by N-succinimidyl 3-(2-pyridyldithio)propionate. The conjugate consisting mainly of one molecule of protein A bound to two molecules of A chains (Mr 107,000) was purified by tandem affinity chromatography on ConA-Sepharose 4B and IgG-Sepharose 4B. The purified protein A-A chain conjugate was able to bind and kill human lymphoma cells coated either with monoclonal mouse IgG2a anti-kappa antibody or with polyclonal rabbit anti-kappa antibody. The cytotoxic activity of protein A-A chain conjugate in conjunction with either mouse or rabbit anti-kappa antibodies was 10 times higher than that of rabbit IgG anti-mouse IgG coupled with A chain on Daudi cells coated with mouse anti-kappa antibody and 100 times higher than that of rabbit anti-kappa antibody coupled with A chain on non-coated Daudi cells. The cytotoxic effect of protein A-A chain conjugate on antibody-coated Daudi cells (9 x 10(-12) M) was comparable with that of ricin toxin on non-coated Daudi cells (2 x 10(-12) M). The results recommend the use of protein A-ricin A chain toxin conjugate as a unique specific toxin for the "in vitro" killing of antibody-coated target cells.     

小鼠睾丸膜联蛋白A1的克隆、表达及定位

目的:克隆、表达小鼠睾丸膜联蛋白A1,并研究其在睾丸中的定位。方法:利用RT-PCR技术从小鼠睾丸组织中扩增膜联蛋白A1的cDNA序列,将该基因插入GST融合表达载体pGEX-5T。以亲和层析法纯化蛋白免疫家兔制备多抗,并做睾丸切片免疫组织化学检测。结果:重组质粒测序结果表明,插入片段与小鼠膜联蛋白A1的序列完全一致。K802重组菌高效表达出相对分子质量为63 000的融合蛋白,表达量占菌体总蛋白的30%。多抗效价达1∶102 400,可特异识别重组蛋白。免疫组织化学显示膜联蛋白A1主要分布于精原细胞核、精子细胞顶体帽及精子胞质残余体内。结论:成功克隆、表达了小鼠膜联蛋白A1基因;膜联蛋白A1在睾丸生精细胞中的不同分布预示其可能与生精过程有关。