合成人IgE肽抗血清抑制Ⅰ型变态反应的实验研究

作者设计合成了5个人IgE多肽片段,分别交联载体蛋白后免疫小鼠,诱生的抗血清有2个在ELISA中对人与鼠IgE分子有交叉反应,3个无反应。5个抗血清均显示有中等程度的被动皮肤过敏反应（PCA）抑制作用。被测试的2个抗血清在大鼠肥大细胞被动致敏试验中也显示了抑制作用。研究结果初步表明,采用人IgE分子受体结合部位的适当残基序列的合成肽疫苗,免疫动物所诱导的抗体可抑制Ⅰ型变态反应。     

人IgE抗体的体外合成与检测

人IgE抗体体外合成与检测系统的建立是进行人IgE调节机理研究的一个基本前提.近年来,随着实验动物IgE调节机理的逐步阐明,越来越多的学者把注意力转向人IgE调节机理的研究,促进了人IgE体外合成与检测技术的进步,使该方面的工作呈现空前活跃的景象.对于1982年以前的工作,Katz曾根据自己的观点做了全面综述.本文拟对目前应用的人IgE抗体体外合成与检测技术做一简要、客观的介绍,期望对国内这方面的工作有所帮助.     

青霉素类过敏反应病人血清中特异性IgE抗体

目的 :探讨青霉素类过敏反应与特异性IgE抗体的关系。方法 :采用放射过敏原吸附试验 (RAST)测定 3 97例青霉素过敏病人血清中 8种抗原决定簇(BPO PLL、PVO PLL、APO PLL、AXO PLL、BPA PLL、PVA PLL、APA PLL、AXA PLL)特异性IgE抗体。结果 :3 97例过敏病人中 ,特异性IgE抗体阳性率为 5 8.9% (2 3 4例 )。其中 ,男性组抗体阳性率显著高于女性组 (P <0 .0 5 )。在所检测的 8种特异性IgE抗体中 ,BPA IgE抗体阳性率 2 5 .44% (1 0 1例 )最高 ,PVA IgE抗体 2 5 .1 9% (1 0 0例 )次之 ,而APA IgE抗体 9.82 % (3 9…     

人肥大细胞的IgE依赖性组胺和类胰蛋白酶分泌

目的　利用人结肠组织的肥大细胞和肥大细胞激活的体外研究系统评价人肥大细胞释放类胰蛋白酶和组胺的能力及其机制。方法　经酶悬浮的人结肠肥大细胞与抗IgE抗体共同培养后记录浓度相关曲线和时间关系曲线。类胰蛋白酶用酶联免疫吸附试验的方法测量 ,而组胺则由一种以玻璃纤维为基础的荧光比色法测量。结果　抗IgE抗体可引起浓度相关性的组胺和类胰蛋白酶释放 ,最大组胺和类胰蛋白酶分泌量分别比基础分泌量超出 2 .7和 2 .5倍以上。抗IgE抗体的作用从加样后 10s开始 ,6min后达高峰并至少持续 15min。百日咳毒素和代谢抑制剂能够分别抑制抗IgE抗体引起的组胺和类胰蛋白酶释放。百日咳毒素还能够减少自发性类胰蛋白酶释放。结论　人结肠肥大细胞在受到抗IgE抗体刺激时具有平行释放类胰蛋白酶和组胺的能力 ,这个过程与肥大细胞膜G蛋白偶联受体的激活有关 ,并消耗能量。肥大细胞自发性释放组胺和类胰蛋白酶的功能可能是通过不同的机制实现的。     

豚鼠过敏抗体的分离纯化及在PCA试验中作用规律的初步研究

目的 建立豚鼠Ⅰ型过敏反应模型,对致敏血清中过敏抗体(IgE、IgG)进行初步分离纯化,并探讨过敏抗体的作用特点.方法 以卵白蛋白(OVA)和Al(OH)_3作为免疫原制备豚鼠Ⅰ型过敏反应模型,ELISA法检测抗体含量,用饱和硫酸铵沉淀、Protein A柱亲和层析的方法 对致敏血清中IgE、IgG抗体进行初步分离纯化,以豚鼠连续被动皮肤过敏试验分别观察两种抗体在致敏后不同时间激发时引起皮肤蓝斑的变化情况.结果 模型组和对照组血清中IgE抗体含量分别为719.3750ng/ml、2.5250 ng/ml,IgG抗体吸光度(A)值分别为0.9921、0.0174,模型组两种抗体含量均比对照组显著升高(P<0.05).豚鼠9 d连续被动皮肤过敏试验中,IgE抗体在5 d PCA时产生的蓝斑直径达到最大,之后持续存在;IgG抗体在2 d PCA时产生蓝斑直径最大,之后迅速下降.结论 成功将致敏血清中两种过敏抗体进行了初步分离纯化,IgE和IgG抗体均参与了豚鼠Ⅰ型过敏反应,IgG抗体较IgE抗体可能作用更为迅速、短暂,有可能成为疫苗Ⅰ型过敏反应毒理学评价的另一主要指标.     

Ⅰ型超敏反应的机制和IgE抗体生成的调节4.可溶性抑制因子对IgE抗体应答的调节作用

IgE在Ⅰ型超敏反应中起决定性作用,因而IgE抗体生成的调节将成为Ⅰ型变态反应性疾病基本疗法之一。为此目的,必须研究IgE应答中各种免疫活性细胞及其所产生的各种可溶性因子的免疫学作用。Okumura和Tada第一个获得直接证据证明,IgE应答需T细胞。他们发现切除胸腺新生大鼠对DNP-载体免疫不产生IgE抗体;补充正常的或载体免疫的胸腺细胞,则此缺陷得以重建。Tada及其同事用大鼠模型,Katz实验室及Ovary等在小鼠中均证明,一些理化措施能干扰、改变IgE抗体应答形式。这些处置手段包括:(1)低或中等剂量全身     

多样性人源天然噬菌体抗体库的构建及初步应用

目的:构建多样性良好的人源天然噬菌体抗体库。方法:从正常人外周血中分离淋巴细胞,以RT-PCR和半巢式PCR扩增重链可变区VH基因和轻链可变区VL基因,以重叠延伸PCR将VH、VL组装成scFv基因,并将其克隆入噬菌粒载体pCANTAB-5E中。以pCANTAB-5E电转化大肠杆菌TG1,构建人源天然噬菌体抗体库,测序分析抗体基因的家族信息和多样性,并用多种抗原对其进行筛选。结果:获得了库容为2×108的人源天然噬菌体抗体库。分别用5种抗原对其进行筛选,均可获得特异性噬菌体抗体的富集。结论:成功地构建了一个多样性良好的人源天然噬菌体抗体库,可用于制备具有应用前景的人源抗体。     

干扰素加强IgE-介导的人嗜硷性细胞的组胺释放需要RNA的合成

在人的血细胞中只有嗜硷性细胞含有组胺。当该细胞膜上的 IgE 与特异性过敏原(如豚草抗原)或抗人 IgE 抗体反应时。组胺及其它过敏症介质(如 SRS-A 及嗜酸性细胞趋化因子)即可释放出。本文作者以前发现,在没有用豚草抗原或抗IgE 攻击之前,将人的白细胞与某些病毒共育可促进组胺的释放,并证明这是由于病毒诱导的 IF 造成的。本文证明,IF 可以加强 IgE 介导的组胺释放,这一强化作用需要 RNA 的合成。     

基于纳米抗体的猫皮屑特异性IgE抗体超敏检测方法的建立和性能评估

目的：通过噬菌体展示技术制备抗人IgE纳米抗体,将其用于磁微粒化学发光平台建立一种猫皮屑特异性IgE抗体超敏检测方法。方法：在WHO/IUIS过敏原数据库中检索猫致敏蛋白信息,合成序列后在原核表达系统中表达和纯化猫皮屑致敏蛋白Fel d 1。使用人源IgE免疫新疆单峰驼提取淋巴细胞中的RNA建立噬菌体展示纳米抗体库,分析库容、多样性和插入率,通过筛选和鉴定获得抗人IgE纳米抗体。使用重组过敏原偶联磁微粒和吖啶酯标记纳米抗体,建立磁微粒化学法猫皮屑特异性IgE抗体检测方法。结果：噬菌体展示库的库容为1.88×108 cfu/ml,插入率为93.6%,纳米抗体纯度>95%。检测方法的线性范围为0.1～100 U/ml,与ImmunoCAP检测系统临床对比有较好的一致性。结论：成功建立了基于纳米抗体的猫皮屑特异性IgE抗体超敏检测方法,为猫过敏性疾病辅助诊断提供了技术基础。     

抗人c-erbB2单克隆抗体的制备及其特异性鉴定

目的:制备小鼠抗人c-erbB2mAb,并进行特异性鉴定。方法:应用计算机软件分析人源c-erbB2抗原表位,人工合成羧基端含优势表位的13肽,与钥孔戚血蓝蛋白(KLH)偶联后,免疫BALB/c小鼠。取免疫小鼠脾细胞与Sp2/0骨髓瘤细胞常规融合,依次经HAT选择培养、间接ELISA法、克隆化和免疫组化染色法筛选出稳定分泌抗天然人源c-erbB2mAb的杂交瘤细胞株。用交叉反应试验和阻断试验检测mAb的特异性。结果:获得1株可稳定分泌抗天然人源c-erbB2抗体的杂交瘤细胞株。该mAb与已知的c erbB2抗原阳性的乳腺癌标本起反应;与其他不表达c-erbB2分子的细胞不起反应。用合成的13肽阻断后,失去与c-erbB2抗原的反应性。结论:用合成的13肽作为免疫原成功地制备出1株抗c-erbB2的mAb。     

人类肝素酶B细胞表位的预测和免疫原性鉴定

目的 预测并鉴定肝素酶(heparanase)蛋白B细胞表位免疫原性.方法 以肝素酶蛋白的氨基酸序列为基础,采用DNAStar分析软件以及Bcepred在线二级结构分析工具分析其蛋白二级结构并预测B细胞表位.根据预测结果 ,采用8分支多抗原肽结构合成针对该表位的抗原肽,将后者与通用型T辅助表位人IL-1β线性短肽(VQGEESNDK,氨基酸163～171)联合免疫日本白毛黑眼兔,检测免疫血清效价,鉴定其特异性和免疫原性.结果 软件预测显示,肝素酶蛋白大亚基的第1～15位(MAP1)、第279～293位(MAP2)及175～189位(MAP3)氨基酸序列最可能为其优势B细胞表位.间接酶联免疫吸附试验、免疫印迹及免疫组化分析,证实MAP1、MAP2及MAP3均能诱导机体产生高滴度抗体,但仅MAP1、MAP2抗体具有高特异性,MAP2抗体与肝癌组织的结合力最强.结论 肝素酶大亚基的第1～15位、第279～293位氨基酸为其优势B细胞表位,其中第279～293位氨基酸的免疫原性最强,这为肝素酶多肽抗体及B细胞优势短肽疫苗研制提供了理论依据.     

Role of peptide antigen for induction of inhibitory antibodies to Streptococcus mutans in human oral cavity

The alanine-rich repeating region (A-region) in the surface protein antigen (PAc) of Streptococcus mutans has received much attention as an antigenic component for vaccines against dental caries. The PAc (residue 361-386) peptide in the A-region possesses a multiple binding motif (L- -V-K- -A) to various HLA-DR molecules and a B-cell core epitope (- Y- - -L- -Y- - - -) that recognizes the inhibiting antibody to S. mutans. In the present study, we investigated the immunogenicity of the PAc (361-386) peptide in humans and regulators of induction of the anti-PAc (361-386) peptide IgA antibody (aPPA) in saliva. The PAc (361-386) peptide was confirmed as an ideal peptide antigen for induction of the inhibiting antibody to S. mutans in 151 healthy human subjects (36.6 +/- 12.6 years old) by quantitative analyses of oral bacteria and ELISA, as the aPPA titre in human saliva decreased significantly in an age-dependent manner. Homozygous DRB1*0405 and 1502, and heterozygous DRB1*0405/1502 showed a negative association with production of aPPA and tended to reduce the number of total streptococci in saliva. In contrast, the DRB1*1501 allele was significantly correlated with a high level of induction of the antibodies, and also tended to reduce lactobacilli and mutans streptococci. Further, peptide immunogenicity was confirmed in NOD-SCID mice grafted with human peripheral blood mononuclear cells. Our results indicate that the interplay between regulators such as age, DRB1 genotype, cytokines, and peptide immunogenicity may provide a potential means for developing a vaccine useful for the prevention of dental caries as well as their diagnosis.     

TIMP-1B细胞表位的预测和鉴定

目的: 预测并鉴定金属蛋白酶组织抑制物-1(TIMP-1)蛋白B细胞表位。方法: 采用DNAStar和BcePred分析软件联合预测TIMP-1的B细胞表位,以此合成8分支多抗原肽结构的表位肽(MAP),并与通用型T辅助表位肽(VQGEESNDK,氨基酸163~171)联合免疫家兔,检测免疫血清效价,用Western blotting和间接酶联免疫吸附测定等方法鉴定其特异性和抗体亲和力。结果: 软件预测显示,TIMP-1的第27~41 位(MAP1)、第57~71 位(MAP2)、第95~109 位(MAP3)和第193~207 位(MAP4)氨基酸序列最可能为其优势B细胞表位。抗体滴度动态检测表明,MAP2、MAP3和MAP4均能诱导产生特异性抗体,其中MAP2和MAP4诱导的抗体水平最高;免疫印迹证实MAP2、MAP3和MAP4诱导产生特异性的TIMP-1抗体;间接ELISA证实MAP4与商品化TIMP-1抗体具有最高的亲和力。结论: TIMP-1的第27~41位和第193~207位氨基酸为其优势B细胞表位,其中第193~207位氨基酸的免疫原性最强,这为TIMP-1多肽抗体和B细胞优势短肽疫苗研制提供了理论依据。     

The neurotransmitter role of calcitonin gene-related peptide in the rat and guinea-pig ureter: effect of a calcitonin gene-related peptide antagonist and species-related differences in the action of omega conotoxin on calcitonin gene-related peptide release from primary afferents.

In the rat and guinea-pig isolated ureter electrical field stimulation of intrinsic nerves (10 Hz for 10 s) produces transient inhibition of evoked (20 mM KCl or 0.1-1 microM neurokinin A) rhythmic contractions by releasing transmitter(s) from peripheral endings of capsaicin-sensitive primary afferents. The C-terminal fragment of human calcitonin gene-related peptide (8-37) blocked the inhibitory effect of electrical field stimulation as well as that produced by exogenous calcitonin gene-related peptide, while leaving unaffected the inhibitory response to isoprenaline. Human calcitonin gene-related peptide (8-37) was devoid of any inhibitory activity of its own but enhanced the amplitude and frequency of KCl-evoked rhythmic contractions in the rat ureter, probably by antagonizing the inhibitory effect of endogenous calcitonin gene-related peptide released by KCl. Omega conotoxin fraction GVIA, a peptide which possesses a potent blocking activity of N-type voltage-sensitive calcium channels, prevented the inhibitory response to electrical stimulation in the guinea-pig ureter, while leaving the response unaffected in the rat ureter. Conotoxin had no effect toward the inhibition produced by exogenous calcitonin gene-related peptide indicating its prejunctional site of action, demonstrated previously in the guinea-pig ureter [Maggi et al. (1990) Neurosci, Lett. 114, 203-206]. Dermorphin, an amphibian peptide with potent agonist activity on mu-type opioid receptors, inhibited the response to electrical stimulation in the guinea-pig ureter but had no effect in the rat ureter.(ABSTRACT TRUNCATED AT 250 WORDS)     

Immunization with calcitonin gene-related peptide reduces the inflammatory response to adjuvant arthritis in the rat

The influence of circulating antibodies to calcitonin gene-related peptide on the inflammatory response was examined in rats with adjuvant-induced arthritis. Rats were immunized with alpha calcitonin gene-related peptide conjugated to thyroglobulin, and circulating antibodies were identified by their capacity to bind radiolabelled rat alpha or human calcitonin gene-related peptide. In unimmunized rats and rats immunized with thyroglobulin alone, the secondary lesions (characterized as paw swelling, nodules on ears and tail, and inflamed nose) produced after adjuvant-induced arthritis were similar. However, at 21 days, when these lesions were maximal, the animals immunized with calcitonin gene-related peptide showed decreased numbers of lesions. An additional marker of disease activity, namely alpha 1 glycoprotein levels in plasma, was also measured. Again, plasma alpha 1 glycoprotein levels were similar in rats that were unimmunized or received thyroglobulin alone, but at 21 days were significantly reduced in animals immunized with calcitonin gene-related peptide. In contrast, the initial foot swelling seen in the first few days after injection of adjuvant was not significantly different in the various groups. The results suggest that antibodies to calcitonin gene-related peptide are able to reduce the severity of the adjuvant arthritis syndrome, and that this peptide contributes to the inflammatory response seen in the later stages of the disease model.     

Immunisation with phage-displayed variable region 2 from meningococcal PorA outer membrane protein induces bactericidal antibodies against Neisseria meningitidis

The immunogenicity and functional activity of antibodies raised in mice against the cyclic disulphide peptide corresponding to the variable region 2 of PorA outer membrane protein from Neisseria meningitidis strain B385 (serosubtype P1.15), displayed on filamentous phage, were evaluated. The epitope, flanked either by cysteine or cysteine and three glycine residues, was expressed as a fusion to PVIII protein from M13. Immunisation of Balb/C mice with either phage generated antibody specific responses. Sera raised against the phage exposing the cyclic peptide through the three-glycine linker recognised the native protein better than those raised against the peptide with no linker. Only the phage displaying the cyclic peptide with linker was capable of inducing antibodies with bactericidal activity. These results indicate the possibility of using phage display for conformational peptide expression for immunisation to elicit functional antibody responses.     

Effects of cerebral lesions on binding sites for calcitonin and calcitonin gene-related peptide in the rat nucleus accumbens and ventral tegmental area.

Binding site densities of [125I]-labelled salmon calcitonin and human calcitonin gene-related peptide were investigated in the rat nucleus accumbens and ventral tegmental area by means of quantitative autoradiography following selective brain lesions. [125I]salmon calcitonin and [125I]human calcitonin gene-related peptide binding sites were highly concentrated in the accumbens, whereas the ventral tegmental area only contained [125I]salmon calcitonin binding sites. Unilateral injection of 6-hydroxydopamine into the ventral tegmental area did not alter [125I]salmon calcitonin and [125I]human calcitonin gene-related peptide binding site densities in the ipsilateral accumbens, while it produced a significant decrease in [125I]salmon calcitonin binding sites in the lesioned ventral tegmental area (-50%). In contrast, following unilateral injection of quinolinic acid into the accumbens, the densities of [125I]salmon calcitonin and [125I]human calcitonin gene-related peptide binding sites were significantly decreased in the lesioned accumbens (-57% and -56%, respectively), while [125I]salmon calcitonin binding site densities were not modified in the ipsilateral ventral tegmental area. The present study clearly suggests that [125I]salmon calcitonin and [125I]human calcitonin gene-related peptide binding sites are located on intrinsic neurons but not on the dopaminergic nerve terminals in the accumbens. Moreover, a certain proportion of [125I]salmon calcitonin binding sites could be present on dopaminergic cell bodies in the ventral tegmental area.     

Lipopeptide immunization without adjuvant induces potent and long-lasting B,T helper,and cytotoxic T lymphocyte responses against a malaria liver stage antigen in mice and chimpanzees

We have employed a 26-amino-acid synthetic peptide based on Plasmodium falciparum liver stage antigen-3 to evaluate improvements in immunogenicity mediated by the inclusion of a simple lipid-conjugated amino acid during peptide synthesis. Comparative immunization by the peptide in Freund's adjuvant or by the lipopeptide in saline shows that the addition of a palmitoyl chain can dramatically increase T helper (Th) cell responses in a wide range of major histocompatibility complex (MHC) class II haplotypes, to the extent that responses were induced in mice otherwise unable to respond to the non-modified peptide injected with Freund's adjuvant, and that the increased immunogenicity of the lipopeptide led to high and longer lasting antibody production (studied up to 8 months). B and T cell responses induced by the lipopeptide were reactive with native parasite protein epitopes, and a lipopeptide longer than ten amino acids was endogenously processed to associate with MHC class I and elicit cytotoxic T lymphocyte (CTL) responses. Finally, the lipopeptide was safe and highly immunogenic in chimpanzees, whose immune system is very similar to that of humans. Our results suggest that relatively large synthetic peptides, carefully chosen from pertinent areas of proteins and incorporating a simple palmitoyllysine, can induce not only CTL, but also strong Th and antibody responses in genetically diverse populations. Lipopeptides engineered in this way are simple to produce and purify under GMP conditions, they are well tolerated by apes, and with the enhanced immunogenicity without the need for adjuvant that we report here, they offer a quick and relatively low-cost route to provide material for human malaria vaccination trials.     

The immunogenicity of a conformationally restricted peptide mimetic of meningococcal lipooligosaccharide

Life-threatening meningitis and septicaemia caused by Neisseria meningitidis are a public health priority, and their prevention by vaccination is a major objective. Meningococcal capsular polysaccharide-based vaccines are effective against the major invasive serogroups, except for serogroup B, the capsule of which mimics human polysaccharides and is poorly immunogenic. An alternative vaccine candidate that has the potential to offer cross-protection against antigenically diverse meningococci is the lipooligosaccharide (LOS). The structurally constrained peptide mimetic, C22, of a bactericidal antibody epitope within LOS was previously shown to elicit cross-reactive antibodies to meningococcal LOS when complexed to NeutrAvidintrade mark as a carrier protein. The immunogenicity of this antigen in H-2(d) (BALB/c) and H-2(k) (C3H/HeN) haplotype mice was further investigated. Anti-LOS immunoglobulin G (IgG) antibody titres increased with the vaccine dose and correlated with the anti-C22 peptide antibody titres in both haplotypes. Antigen-stimulated Th1/Th2 cytokine secretion by splenocytes and antibody isotypes indicated a Th2-type immune response with IgG1 antibodies and a low titre of IgG2b. There was no serum bactericidal activity observed against the meningococcus.     

Clinical validation of the "in silico" prediction of immunogenicity of a human recombinant therapeutic protein

Antibodies elicited by protein therapeutics can cause serious side effects in humans. We studied immunogenicity of a recombinant fusion protein (FPX) consisting of two identical, biologically active, peptides attached to human Fc fragment. EpiMatrix, an in silico epitope-mapping tool, predicted promiscuous T-cell epitope(s) within the 14-amino-acid carboxy-terminal region of the peptide portion of FPX. On administration of FPX in 76 healthy human subjects, 37% developed antibodies after a single injection. A memory T-cell response against the above carboxy-terminus of the peptide was observed in antibody-positive but not in antibody-negative subjects. Promiscuity of the predicted T-cell epitope(s) was confirmed by representation of all common HLA alleles in antibody-positive subjects. As predicted by EpiMatrix, HLA haplotype DRB1*0701/1501 was associated with the highest T-cell and antibody response. In conclusion, in silico prediction can be successfully used to identify Class II restricted T-cell epitopes within therapeutic proteins and predict immunogenicity thereof in humans.