Effect of myasthenic IgG on degradation of junctional acetylcholine receptor

We investigated the effect of the lgG from patients with myasthenia gravis (MG) on the degradation of normal rat junctional acetylcholine receptor (AChR) labeled with ¹²⁵l-α-bungarotoxin (BuTx) and calculated the degradation rate (DR). The DR for the lgG from these patients was significantly higher than that from healthy volunteers and patients with other autoimmune diseases. For MG, DR was significantly correlated with the severity of the disease but not with anti-AChR antibody titer. DR was accelerated by lgG from patients with generalized MG whose antibody titers were in the normal range and by lgG from patients with ocular MG. These results indicate that measurement of the DR of junctional AChR in normal rats is more closely correlated with the severity of the disease than is measurement of anti-AChR antibody and that the former is a sensitive and confirmatory method for evaluating MG. © 1993 John Wiley & Sons, Inc.     

Antibodies against saline-soluble components of skeletal muscle in myasthenia gravis

Summary Antibodies against phosphate-buffered-saline extracts (SE) of non-acetylcholine receptor (AChR) skeletal muscle antigens were found in patients with myasthenia gravis (MG). The antigenicity of SE was distributed in three fractions with molecular masses of over 200 kDa, 90–150 kDa and 7–14 kDa on gel filtration. These fractions shared common antigenicities. Further analysis of 90–150 kDa fractions on sodium dodecyl sulphate polyacrylamide gel electrophoresis showed five major bands, ranging from 105 kDa to 275 kDa. The antibodies against SE were detected in 52% (58/112) of the MG patients; incidence and titres were higher in the thymoma group (n=21; 90% and 0.872 respectively) than in the non-thymoma group (n=91; 43% and 0.200, P<0.001). In patients without a thymoma, these antibodies were frequently observed in late-onset disease and the severe generalized form (P<0.01). In 4 of 7 ocular MG patients without anti-AChR antibodies, low but appreciable levels of anti-SE antibodies were found. In 73% (11/15) of generalized MG patients treated with prednisolone and thymectomy, anti-SE antibody titres changed in association with those of anti-AChR antibodies and with the clinical course. Both antibody titres increased synchronously in patients who developed crises.     

Induction of antibody responses to breast carcinoma associated mucins using synthetic peptide constructs as immunogens

A strategy for directing and enhancing B cell immune responses against synthetic peptide determinants has been developed in order to produce antibodies specifically against protein epitopes of clinical relevance. A peptide sequence based upon the MUC-1 mucin protein core was selected for this purpose since anti-MUC-1 antibodies have proven diagnostic application and therapeutic potential in human breast and ovarian cancer. Peptide constructs were synthesised co-linearly linking the immunodominant B cell determinant region, PDTRPAP, in the protein core of the MUC-1 mucin, to sequence 111 – 120 of influenza haemagglutinin A/X-31, a determinant recognised by T helper cells through association with MHC class II molecules. Induction of anti-MUC-1 antibodies to the B cell determinant region by immunisation with peptide was shown to be dependent upon both the presence and the position of the T cell determinant. In addition, haplotype mismatching with respect to the T cell determinant resulted in a significant lowering of the anti-MUC-1 antibody response in peptide construct immunised mice. These findings are relevant to the design of immunogens to produce antibodies against peptide epitopes of tumour associated proteins and glycoproteins.     

乙酰胆碱受体抗体量与眼型重症肌无力病情关系的实验观察

目的　观察血清乙酰胆碱受体抗体 (Ach Rab)含量与眼型重症肌无力患者病情程度和发展为全身型重症肌无力的关系。方法　 2 0例眼型重症肌无力患者按受累程度分为轻、中、重三组 ,采用固相酶免疫吸附法测定血清 Ach Rab含量 (P/ N值 )。结果　对照组和病情轻、中、重三组血清 P/ N值分别为 :0 .6 7± 0 .45、0 .78± 0 .30、1.16± 0 .18和 1.5 1± 0 .13。轻度组与对照组比较无显著差异 (P >0 .0 5 ) ,中度组与轻度组比较差异显著 (P <0 .0 5 ) ,重度组与中度组比较有非常显著差异 (P <0 .0 1)。3例 P/ N值明显高患者 (中度组 1例、重度组 2例 ) 2年后发展成全身型。结论　 P/ N值可反映患者病情程度和提供眼型重症肌无力发展为全身型重症肌无力的预兆信息。     

Interleukin 6 Influences Germinal Center Development and Antibody Production via a Contribution of C3 Complement Component

Mice rendered deficient for interleukin (IL) 6 by gene targeting were evaluated for their response to T cell–dependent antigens. Antigen-specific immunoglobulin (Ig)M levels were unaffected whereas all IgG isotypes showed varying degrees of alteration. Germinal center reactions occurred but remained physically smaller in comparison to those in the wild-type mice. This concurred with the observations that molecules involved in initial signaling events leading to germinal center formation were not altered (e.g., B7.2, CD40 and tumor necrosis factor R1). T cell priming was not impaired nor was a gross imbalance of T helper cell (Th) 1 versus Th2 cytokines observed. However, B7.1 molecules, absent from wild-type counterparts, were detected on germinal center B cells isolated from the deficient mice suggesting a modification of costimulatory signaling. A second alteration involved impaired de novo synthesis of C3 both in serum and germinal center cells from IL-6–deficient mice. Indeed, C3 provided an essential stimulatory signal for wild-type germinal center cells as both monoclonal antibodies that interrupted C3-CD21 interactions and sheep anti–mouse C3 antibodies caused a significant decrease in antigen-specific antibody production. In addition, germinal center cells isolated from C3–deficient mice produced a similar defect in isotype production. Low density cells with dendritic morphology were the local source of IL-6 and not the germinal center lymphocytes. Adding IL-6 in vitro to IL-6–deficient germinal center cells stimulated cell cycle progression and increased levels of antibody production. These findings reveal that the germinal center produces and uses molecules of the innate immune system, evolutionarily pirating them in order to optimally generate high affinity antibody responses.     

青年人群血清甲_3型流感抗体检测和流行株的抗原性分析

采集４５０例战士血清标本，分别用国家代表株甲３／济防／１５／９０（Ｈ３Ｎ２）和甲３／北京／３２／９２（Ｈ３Ｎ２）作血清血凝抑制抗体测定，青年对甲３型抗体阳性率为６０％～６７％，其ＧＭＴ为３４～４５。１９９４～１９９５年两年中在军营人群中分离到３株Ｈ３Ｎ２毒株流行株，分别应用国际、国家和地方代表株作抗原性分析，证明流行株与它们之间抗原性有明显差异。本文分离到的３株流行株均上送国家流感中心鉴定，证实为Ｈ３Ｎ２亚型毒株。     

活动性结核标志物'H-多肽的实验与临床研究

本题研究是经免疫学途径直接检测人体感染结核菌的情况，为现代结核病的实验诊断、临床监测、流行病调查提供了一个全新的检验指标。作者首先发现了一种仅存在于活动性结核病患者体液中的蛋白成份—活动性结核标志物（ＡｃｔｉｖｅＴｕｂｅｒｃｕｌｏｓｉｓＭａｒｋ—ＡＴＭ）１Ｈ—多肽；并为之创立了独特的检测方法，经四年多临床１９４６０例样本调查中确定了ＡＴＭ的临床价值。将ＡＴＭ检测与ＯＴ皮试、酶联免疫ＥＬＩＳＡ、ＤＮＡ探针、ＰＣＲ基因扩增技术及典型病例组患者行Ｘ线计算机断层摄影（ＣＴ）、磁共振像（ＭＲＩ）等多组对比试验中，实验与临床研究资料分析证明：ＡＴＭ检测的总敏感度为８６．０６％、特异度９６．２４％、准确度９３．４５％、诊断效率为８２．８２％、批内ＣＶ１．２％、批间ＣＶ２．０％、Ｐ＜０．０５。经ＮＭＲ光谱分析结构含有ＣＣＨ２官能团。     

间接荧光抗体试验检测日本血吸虫感染家兔血清中特异性抗体水平的动态变化

用尾蚴、雌虫、雄虫和血吸虫感染兔肝组织内虫卵冰冻切片抗原进行间接荧光抗体试验（ＩＦＡＴ），观察日本血吸虫感染家兔血清中特异性抗体的动态变化。抗尾蚴、成虫（雌、雄虫）、虫卵抗体检出的最早时间分别为３ｗｋ、３ｗｋ、４ｗｋ，其抗体滴度高峰分别在感染后７ｗｋ、１０～１２ｗｋ和１０ｗｋ。以抗尾蚴抗体水平最高，抗虫卵抗体次之，抗雌、雄虫抗体较低。这为全面了解感染宿主对血吸虫各期抗原（尾蚴、雌、雄虫、虫卵）的免疫反应及免疫学诊断提供了新的资料     

B细胞杂交瘤技术制备抗同种特异T细胞膜抗原单克隆抗体

目的：为进一步分析ＴＣＶ免疫诱导同种免疫反应低下的机制。方法：采用Ｂ细胞杂交瘤技术获得分泌单克隆抗体的杂交瘤细胞。结果：两次的细胞融合中共得到１２株稳定分泌单抗的杂交瘤细胞，为分析抗体在ＴＣＶ中的作用提供条件。结论：ＴＣＶ免疫可引起抗ＴＣＶ细胞抗体的产生，以同系免疫的方法得到的活化Ｂ细胞用于Ｂ细胞杂交生产单抗是可行的。     

High level production of soluble single chain antibodies in small-scale Escherichia coli cultures

We have investigated the effect of growth and induction conditions on the production of soluble single-chain Fv antibody fragments in Escherichia coli under the control of wt lac promoter. The scFv was directed into the periplasmic space by a pelB leader sequence. Addition of sucrose to the medium gave a 15–25-fold increase in the yield of soluble scFv-phOx (3.0 mg/l) for bacterial shake-tube cultures and an increase of 80–150-fold (16.5 mg/l) for shake-flask cultures. Using flask culture in the presence of 0.4 M sucrose, a significant amount of scFv was released into the medium. We found that the scFv could be made to accumulate in the periplasm or be secreted into the medium by simply changing the incubation conditions and the concentration of the inducer. The ratio between soluble antibody fragments and insoluble scFv aggregates proved to be dependent on the strength of the promoter. Lowering the incubation temperature below 20°C had no effect on the yield of soluble antibody fragments in the periplasm, but they were no longer secreted into the medium. An example of high level production in shake-flask cultures and one-step purification by immobilized metal affinity chromatography (IMAC) is described for a soluble scFv specific for the T cell surface antigen CD3. The biological activity of the purified anti-CD3 scFv was demonstrated by flow cytometry. This method should be especially useful for the functional screening of a large number of clones in small-scale cultures.