ADCC效应在抗HIV感染中的作用

抗体依赖性细胞介导的细胞毒性作用(antibody-dependent cell-mediated cytotoxicity,ADCC)是一种固有免疫和适应性免疫相结合的免疫学效应。ADCC效应主要是通过效应细胞膜表面的受体IgG Fc受体(Fc receptor,FcR)如FcγRIIIa(CD16)、FcγRIIc(CD32)、FcγRI(CD64)识别靶细胞膜表面抗原,结合相应IgG抗体的Fc段而促发效应细胞脱颗粒和细胞因子分泌的一类细胞毒效应。对人类免疫缺陷病毒(human immunodeficiency virus,HIV)感染已有研究证实了,ADCC效应在控制HIV感染中发挥着重要作用。现对ADCC效应在抗HIV感染中的作用作一综述。     

IgE介导的肥大细胞脱颗粒信号转导途径的研究进展

肥大细胞(mast cell,MC)是过敏性疾病的关键细胞之一.机体的过敏反应很大程度依赖于肥大细胞膜上的特异性受体FcεRI.肥大细胞膜上交联的FcεRI引发了下游的一系列信号事件并导致脱颗粒,包括细胞因子及趋化因子产生以及白三烯的释放.由于IgE在过敏反应中的重要作用,现在的研究主要集中在FcεRI下游的信号事件.其脱颗粒的分子机制是一个由多种蛋白质分子介导的,各个环节受到精确调控的复杂过程.对肥大细胞脱颗粒分子机制的深入研究将给过敏性疾病提供一个新的治疗方案.     

小鼠抗天花粉蛋白IgE单克隆抗体的制备、分离和鉴定(英文)

天花粉蛋白是中药天花粉的有效引产成份,在应用中它偶尔也引起过敏反应。我们用杂交瘤技术建立了一株分泌抗天花粉蛋白特异性IgE单克隆抗体的杂交瘤细胞系。在实验中,二次免疫的C57 BL/6 J小鼠的肠系膜淋巴结细胞和脾细胞分别被用来同NSI骨髓瘤细胞进行融合。虽然在融合前动物血清IgE抗体效价仅为40～160 PCA滴度,但用肠系膜淋巴结细胞进行的4次融合都产生了IgE杂交瘤。阳性率为1.0-6.7%。对比之下,用脾细胞进行的另外两次融合却没有观察到IgE杂交瘤产生,统计结果说明差异显著(P<0.05)。该IgE单克隆抗体可以在体内和体外诱发大鼠肥大细胞脱颗粒。56℃热处理2小时能使该抗体诱导PCA反应的能力完全丧失,然而却不影响其结合抗原的能力。对该单克隆抗体的特异性的鉴定表明,它可以特异性地识别精制天花粉蛋白和结晶天花粉蛋白上的抗原决定簇。     

抗体依赖细胞介导的细胞毒性效应在抗人类免疫缺陷病毒1型感染过程中的作用

抗体依赖细胞介导的细胞毒性(antibody-dependent cell-mediated cytotoxicity,ADCC)效应是宿主抵抗病原微生物和清除病变细胞的一种重要的免疫反应机制.通过ADCC途径发挥作用的效应细胞包括:自然杀伤(NK)细胞、巨噬细胞、中性粒细胞等.     

RBL-2H3细胞系在过敏性疾病中的应用

肥大细胞在过敏性疾病发生中起关键作用,而RBL-2H3细胞系作为大鼠嗜碱性粒细胞系(rat basophilic leukemia,RBL)的一个亚系,可以表达肥大细胞的许多特性和功能,因此常作为过敏性疾病研究的替代模型。RBL-2H3细胞系常用作过敏反应中肥大细胞脱颗粒和激活机制方面的研究,此外,该细胞系在抗原特异性IgE的检测、过敏原的分离鉴定和临床过敏性疾病诊断等方面也有较高的应用价值。本文重点综述了RBL-2H3细胞系在过敏性疾病研究的多个领域中的应用情况。     

人CD137抗体促进NK细胞对乳腺癌细胞特异性杀伤作用的体外研究

目的探讨人自然杀伤(NK)细胞在CD137抗体作用下通过抗体依赖性细胞毒性作用(ADCC)介导对乳腺癌细胞的杀伤作用。方法NK细胞表型和细胞因子检测实验分组:阴性对照组(未用人CD137抗体处理的NK细胞)、CD137抗体处理组(10μg/mL人CD137抗体处理4 h的NK细胞);NK细胞毒性检测实验分组:根据体系中是否添加NK细胞、人CD137抗体和西妥昔单抗分为8组。流式细胞术检测两组NK细胞表面CD16分子的表达情况,酶联免疫吸附测定(ELISA)法检测两组NK细胞培养上清液中干扰素(IFN)-γ和肿瘤坏死因子(TNF)-α的浓度,乳酸脱氢酶(LDH)法检测8组反应体系中表皮生长因子受体(EGFR)高表达乳腺癌细胞系MDA-MB-231和EGFR低表达乳腺癌细胞系MDA-MB-453的杀伤比例,并采用t检验或析因分析进行统计学分析。结果与阴性对照组比较,CD137抗体处理组CD16+NK细胞比例(79.57﹪±0.92﹪比90.43﹪±0.67﹪)、细胞因子IFN-γ浓度[(388.90±7.02)pg/mL比(523.90±1.90)pg/mL]和TNF-α浓度[(20.59±4.09)pg/mL比(47.22±2.14)pg/mL]均升高,差异有统计学意义(P<0.05);MDA-MB-231细胞杀伤的三因素析因分析结果显示:NK细胞、人CD137抗体和西妥昔单抗3个因素分别对MDA-MB-231细胞的杀伤都有作用(F=5227.276、201.473、1792.242,P均<0.001),3个因素两两之间的交互作用对MDA-MB-231细胞的杀伤也都有作用(F=183.903、1517.187、33.483,P均<0.001),3个因素的二级交互作用差异有统计学意义(F=41.505,P<0.001)。结论人CD137抗体可增强NK细胞分泌细胞毒性因子IFN-γ和TNF-α的能力,同时可上调NK细胞表面CD16分子的表达,从而使得NK细胞可能通过西妥昔单抗介导的ADCC作用增强对表皮生长因子受体(EGFR)高表达乳腺癌细胞的杀伤作用。     

约氏疟原虫与伯氏疟原虫诱导感染小鼠产生保护性抗体的特点研究

比较约氏疟原虫(Plasmodium yoelii)与伯氏疟原虫(Plasmodium berghei)再次感染模型特异性抗体产生的差异,追溯相应虫体抗原的表达特点。建立约氏疟原虫与伯氏疟原虫再次感染鼠疟模型,ELISA检测特异性抗体水平;Western Blot检测血清中优势抗体反应特点;检测两种虫株的MSP-1重组蛋白与免疫血清的反应程度;质谱鉴定伯氏疟原虫诱导免疫血清中优势抗体的抗原特点。ELISA表明小鼠免疫血清能够与相对应虫株蛋白产生特异性反应,二次感染后的免疫血清具有抗体产生增强的现象;免疫血清与重组的MSP-1蛋白具有较好的反应性,反应水平具有种属差异性。与约氏疟原虫产生以抗MSP-1抗体为主的反应模式不同,伯氏疟原虫免疫血清还增加了分子量55 kD的反应条带,通过蛋白质谱鉴定提示可能是PbANKA_0702800,PbANKA_020920,PbANKA_110220等疟原虫表面蛋白。结果表明,抗疟原虫有效抗体的产生在宿主抵抗疟原虫感染尤其是再次感染的过程中发挥至关重要的作用。     

百白破混合制剂接种后ADCC和NK细胞活性的变化

<正>自然杀伤细胞(NK细胞)是对某种靶细胞具有细胞损伤活性的正常未致敏淋巴细胞。NK细胞活性与抗体依赖性细胞介导的细胞毒性(ADCC)活性不同,是在无特异性抗体的情况下对靶细胞所呈现的活性,因而,它在肿瘤免疫和病毒感染时作为免疫活性细胞参与初期防御作用较之ADCC活性更重要。     

抗α2δ1/CD3双特异性抗体的制备和功能的初步研究

目的:构建抗α2δ1和CD3的双特异性抗体,并在体外初步评价其杀伤肝癌细胞的功能。方法:通过基因工程技术,构建BiTE形式的anti-α2δ1/CD3双特异性抗体(BsAb),转染Expi 293F细胞96h后,使用镍离子亲和色谱纯化出双特异性抗体,使用流式细胞术检测anti-α2δ1/CD3BsAb对α2δ1和CD3的结合性质,使用Perkin Elmer Operetta高内涵成像仪测定anti-α2δ1/CD3BsAb介导细胞毒性T淋巴细胞(CTLs)对高表达α2δ1的人肝癌细胞Hep-12的杀伤效应,ELISA法检测杀伤过程中CTLs分泌hIL-2和hIFN-γ的变化。结果:anti-α2δ1/CD3 BsAb可以特异性结合α2δ1和CD3,anti-α2δ1/CD3 BsAb可以有效介导CTLs靶向杀伤高表达α2δ1的人肝癌细胞Hep-12,其介导杀伤Hep-12细胞的EC_(50)为8pmol/L,对于低表达α2δ1的人肝癌细胞Hep-11,anti-α2δ1/CD3 BsAb不能介导CTLs发挥杀伤作用,并且在杀伤过程中Hep-12细胞组CTLs释放的hIL-2和h IFN-γ比Hep11细胞组显著增多(P 0.05)。结论:anti-α2δ1/CD3 BsAb能有效介导CTLs体外杀伤高表达α2δ1的人肝癌细胞Hep-12,为双特异性抗体的肝癌免疫治疗奠定了一定的基础。     

耐受性树突状细胞预防和治疗卵清蛋白过敏小鼠的的研究

目的 比较腺病毒重组CTLA4Ig/α4β7诱导的耐受性树突状细胞对卵清蛋白(OVA)致敏小鼠的预防和治疗效果.方法 BALA/c小鼠32只,分为4组.基础致敏24h后回输耐受性树突状细胞为预防组;肠道激发4h后回输耐受性树突状细胞为治疗组;回输生理盐水为阴性对照组和OVA过敏小鼠为阳性对照组.观察各组小鼠过敏症状缓解情况;HE染色观察空肠形态;甲苯胺兰染色观察小肠固有层肥大细胞聚集及脱颗粒现象;ELISA测定各组血清中OVA特异性IgE水平.结果 与阳性对照组相比,治疗组小鼠OVA特异性IgE水平显著降低(0.25±0.05 vs 0.17±0.03) (P ＜0.05);体重增长明显(3.16 g±0.75 g vs 5.04 g±0.49 g)(P ＜0.05);腹泻症状减轻;HE染色可见治疗组小肠绒毛中上皮细胞局灶性坏死、脱落,固有层炎症细胞浸润现象明显改善;肥大细胞聚集和脱颗粒现象改善.而预防组较阳性对照组过敏症状、小肠形态学及OVA特异性IgE水平差异均无统计学意义.结论Ad CTLA4Ig/Adα4β7修饰的致耐受性树突状细胞对卵清蛋白过敏小鼠具有治疗作用而无预防作用.     

Immunologic properties of mast cells from rats infected with Nippostrongylus brasiliensis.

The concentration of IgE in the serum of Sprague-Dawley rats increased after infection with Nippostrongylus brasiliensis (NB). The IgE concentration in normal rats was less than 1 mug/ml. After re-infection with NB, the concentration increased in 100 to 300 mug/ml. Mast cells were purified from peritoneal cells of both normal and NB-infected animals. Purified mast cells from the infected animals released histamine upon exposure to NB antigen. The antibody specific for IgE released histamine from purified mast cells of both normal and infected animals. Dose-reponse curves of histamine release suggested that mast cells from NB-infected animals bear more IgE molecules than normal mast cells. Binding of 125I-labeled rat E myeloma protein with normal mast cells was demonstrated by autoradiography. Under the same experimental conditions, mast cells of infected animals were not labeled with 125I-IgE. Mast cells from both normal and infected animals failed to combine 125I-labeled IgG. The number of IgE molecules bound per mast cell was determined by incubating 125I-labeled IgE with purified mast cells. When mast cells were incubated incubated in 0.6 to 2 mug/ml of IgE, the number of IgE molecules combined with the mast cells from infected animals was about 10% of that bound with normal mast cells. The results indicated that a large proportion of IgE receptors on mast cells of infected animals was occupied by their own IgE. No significant difference was observed between normal mast cells and those of infected animals with respect to histamine content and intracellular levels of cyclic nucleotides.     

Triggering of histamine release from rat mast cells by divalent antibodies against IgE-receptors.

Antibodies against receptor molecules for IgE on rat basophilic leukemic (RBL) cells were prepared by immunization of a rabbit with immune precipitates composed of IgE-receptor complexes and anti-IgE. Antibodies against cell surface components were specifically purified by using RBL cells and rendered specific for mast cells by appropriate absorption. The major antibodies in the final preparation (anti-RBL) were directed against receptor molecules. It was found that the F(ab')2 fragments of anti-RBL induced histamine release from rat mast cells and caused immediate skin reactions in normal rats. These reactions by anti-RBL or its F(ab')2 fragments were inhibited if the receptors on mast cells had been saturated with IgE. The Fab' fragments of anti-RBL could bind with receptors on RBL cells and blocked passive sensitization of mast cells with IgE antibodies, but failed to induce skin reactions and histamine release from normal mast cells. Sensitization of normal rat skin with the Fab' fragment followed by an i.v. injection of anti-rabbit IgG induced skin reactions. The results indicated that bridging of receptor molecules by divalent anti-receptor antibody triggered mast cells for histamine release.     

胃促胰酶和肥大细胞在豚鼠过敏性休克死亡的应用

目的:建立豚鼠过敏性休克模型,研究胃促胰酶和肥大细胞在过敏性休克诊断上的应用。方法:20只清洁级豚鼠随机分为10只实验组和10只对照组,应用混合人血清构建的过敏模型,ELISA方法测定豚鼠血清Ig E含量,免疫组化染色观察胃促胰酶在喉头、气管、肺、胃、肠的表达,肥大细胞特殊染色计数肥大细胞。结果:实验组豚鼠有70%发生过敏性休克死亡,实验组豚鼠血清中Ig E的含量显著高于对照组豚鼠(P0.05),实验组豚鼠于喉头、气管、肺胃促胰酶的表达高于对照组(P0.05),实验组豚鼠于喉头、气管、肺、胃的肥大细胞总数高于对照组豚鼠(P0.05),肺组织观察到肥大细胞脱颗粒。结论:胃促胰酶和肥大细胞可以为过敏性休克死亡的法医学鉴定提供参考。     

Role of TGF-beta 1 on the IgE-dependent anaphylaxis reaction

TGF-beta1 is a member of a family of polypeptide factors that control proliferation, differentiation, chemotaxis, and other functions in many cell types. TGF-beta1 has been shown to inhibit many immunologic functions. However, here we report that TGF-beta1 has an important role in the elicitation of IgE-dependent allergic reactions. The synthetic antisense TGF-beta1 oligonucleotides dose-dependently inhibit passive cutaneous anaphylaxis (PCA) reaction and histamine release from the mast cells activated by anti-DNP IgE in rats. The level of cAMP in mast cells, when antisense TGF-beta1 oligonucleotides was added, significantly increased approximately 7-fold compared with that of basal cells. The antisense TGF-beta1 oligonucleotides also had a significant inhibitory effect on anti-DNP IgE-induced TNF-alpha release from mast cells. In situ hybridization analysis showed that the PCA reaction sites treated with antisense TGF-beta1 oligonucleotides exhibited no detectable levels of TGF-beta1 and L-histidine decarboxylase mRNA after anti-DNP IgE stimulation, whereas the PCA reaction sites treated with sense TGF-beta1 oligonucleotides possessed significant amounts of their mRNA. Additionally, neutralizing Ab to TGF-beta1 blocked the PCA reaction significantly, but its Ab did not inhibit peritoneal mast cell-released histamine upon treatment with anti-DNP IgE. Our results suggest that TGF-beta1 is critical to the development of IgE-dependent anaphylaxis reactions.     

Development of rat mast cells in vitro. I. Differentiation of mast cells from thymus cells.

Mast cells were differentiated by long-term culture of rat thymus cells on rat embryonic fibroblasts monolayers. Mature mast cells obtained in the culture were morphologically similar to normal peritoneal and thoracic mast cells and possessed specific receptors for IgE on their surface. In culture, blast cells appeared on the monolayer several days after seeding of thymus cells. These cells developed into young mast cells in the monolayer and became free in the culture medium with maturation. Receptors for IgE were detected on the surface of mastoblasts which contained a small amount of metachromatic granules. Evidence was obtained which suggested that the number and/or affinity of the receptors for IgE increases with maturation of mast cells. It was found that some mast cells differentiated from monolayers of embryo cells without seeding thymus cells. The present experiments, however, clearly showed that mast cells can be differentiated from thymus cell culture without monolayer. It appears that both thymus and embryo tissues contain precursors of mast cells.     

Systemic effects of ingested Lactobacillus Rhamnosus: inhibition of mast cell membrane potassium (IKCa) current and degranulation

Exposure of the intestine to certain strains lactobacillus can have systemic immune effects that include the attenuation of allergic responses. Despite the central role of mast cells in allergic disease little is known about the effect of lactobacilli on the function of these cells. To address this we assessed changes in rat mast cell activation following oral treatment with a strain of Lactobacillus known to attenuate allergic responses in animal models. Sprague Dawley rats were fed with L. rhamnosus JB-1 (1×10(9)) or vehicle control for 9 days. Mediator release from peritoneal mast cells (RPMC) was determined in response to a range of stimuli. Passive cutaneous anaphylaxis (PCA) was used to assess mast cell responses in vivo. The Ca(2+) activated K(+) channel (KCa3.1) current, identified as critical to mast cell degranulation, was monitored by whole cell patch-clamp. L. rhamnosus JB-1 treatment lead to significant inhibition of mast cell mediator release in response to a range of stimuli including IgE mediated activation. Furthermore, the PCA response was significantly reduced in treated rats. Patch-clamp studies revealed that RPMC from treated animals were much less responsive to the KCa3.1 opener, DCEBIO. These studies demonstrate that Ingestion of L. rhamnosus JB-1 leads to mast cell stabilization in rats and identify KCa3.1 as an immunomodulatory target for certain lactobacilli. Thus the systemic effects of certain candidate probiotics may include mast cell stabilization and such actions could contribute to the beneficial effect of these organisms in allergic and other inflammatory disorders.     

Development of mast cells in vitro. II. Biologic function of cultured mast cells.

Mast cells were obtained by long term culture of rat thymus cells on rat embryonic fibroblast monolayers. Pure mast cell preparations obtained culture were incubated with 125I-labeled rat E myeloma protein to study receptors for IgE on their surface. When the cells were obtained after 35 to 45 days culture, the average number of receptors per mast cell was 100,000 to 400,000. An equilibrium constant of the binding reaction between their receptor and rat IgE was in the order of 108 M-1. The histamine content of the cultured mast cells was 0.2 to 5 mug/106 cells. The measurement of histamine content in mast cells recovered after different periods of culture suggested that the histamine content increased with maturation. Even after 45 to 50 days culture, the histamine content of cultured mast cells was significantly lower than that in rat peritoneal mast cells. The cultured mast cells were passively sensitized in vitro with rat IgE antibody against Nippostrongylus brasiliensis. The sensitized cells released histamine upon incubation with the antigen. It was also found that cultured mast cells released histamine upon exposure to compound 48/80. These results indicated that cultured mast cells have physiologic functions similar to those of normal rat mast cells, but they have not reached full maturation.     

Cyclical mechanical stretch enhances degranulation and IL‐4 secretion in RBL‐2H3 mast cells

Mast cells are widely distributed in the body and affect their surrounding environment through degranulation and secretion of cytokines. Conversely, mast cells are influenced by environmental stimuli such as cyclical mechanical stretch (CMS), such as that induced by heartbeat and respiration. Peripherally distributed mast cells are surrounded by extracellular matrix, where they bind IgE on their surface by expressing the high‐affinity Fc receptor for IgE (FcεRI), and they release mediators after cross‐linking of surface‐bound IgE by allergen. To analyse how CMS affects mast cell responses, we examined the effect of applying CMS on the behaviour of IgE‐bound mast cells (RBL‐2H3 cell line) adhering to fibronectin as a substitute for extracellular matrix. We found that CMS enhanced FcεRI‐mediated secretion in the presence of antigen (2,4‐dinitrophenol–bovine serum albumin). CMS increased expression of IL‐4 mRNA and secretion of IL‐4 protein. Western blot analysis showed that CMS changes the signal transduction in mitogen‐activated protein kinases and AKT, which in turn alters the regulation of IL‐4 and increases the secretion of IL‐4. These results suggest that CMS modulates the effect of mast cells on inflammation and resultant tissue remodelling. Understanding how CMS affects mast cell responses is crucial for developing therapies to treat mast cell‐related diseases. Copyright © 2013 John Wiley & Sons, Ltd.     

IgE immunotoxins. Effect of an IgE-ricin A chain conjugate on rat skin histamine content

Immunotoxins--toxins covalently conjugated to specific antibodies--have been studied as possible agents in the treatment of cancer. The avid binding of IgE antibodies to FcR on mast cells and basophils suggested the possible use of an IgE-immunotoxin in the treatment of malignant mastocytosis or as a method to generate mast cell-depleted animals for study. To this end, the effect of a covalent conjugate of rat myeloma IgE and ricin A chain on rat cutaneous mast cells was examined in vivo. IgE-ricin A chain was capable of binding to and sensitizing cutaneous mast cells in vivo as indicated by a bluing response to intracutaneous anti-ricin A chain. IgE-ricin A chain, given either as a single dose or, even more effectively, as two split doses, significantly reduced cutaneous histamine content for 6 to 8 days. Neither a mixture of IgE and ricin A chain that were not conjugated nor the induction of cutaneous mast cell degranulation with anti-IgE affected cutaneous histamine levels. Therefore, IgE-ricin A chain produces a prolonged depletion of cutaneous histamine levels.     

IgE by Itself Affects Mature Rat Mast Cell Preformed and De Novo-Synthesized Mediator Release and Amplifies Mast Cell Migratory Response

Background

Immunoglobulin E (IgE) binds to high affinity receptor FcεRI numerously expressed on mast cells. Recent findings have revealed that IgE by itself may regulate various aspects of mast cell biology, however, detailed data is still limited.

Methodology/Findings

Here, we have examined the influence of IgE alone, used at different concentrations, on mast cell activity and releasability. For the study we have employed in vivo differentiated mature tissue mast cells isolated from rat peritoneal cavity. Mast cells were exposed to IgE alone and then the release of preformed and de novo-synthesized mediators, surface FcεRI expression and mast cell migratory response were assessed. IgE by itself was found to up-regulate FcεRI expression and activate mast cells to degranulation, as well as de novo synthesis and release of cysteinyl leukotrienes and TNF. We have provided evidence that IgE alone also amplified spontaneous and CCL5- or TNF-induced migration of mast cells. Importantly, IgE was effective only at concentrations ≥ 3 µg/mL. A molecular basis investigation using an array of specific inhibitors showed that Src kinases, PLC/PLA₂, MAP kinases (ERK and p38) and PI3K were entirely or partially involved in IgE-induced mast cell response. Furthermore, IgE alone stimulated the phosphorylation of MAP kinases and PI3K in rat mast cells.

Conclusion

Our results clearly demonstrated that IgE by itself, at higher concentrations, influences mast cell activity and releasability. As there are different conditions when the IgE level is raised it might be supposed that in vivo IgE is one of the important factors modulating mast cell biology within tissues.