低聚肽调节免疫功能及其对冠状病毒感染的影响

低聚肽是蛋白质分解为氨基酸过程中的中间产物,其不仅具有蛋白质的营养支撑作用,还具有强大的调节抗氧化和免疫功能的作用。本文就动物、植物和微生物来源的低聚肽对免疫系统的调控作用进行了论述,对其提高免疫系统功能及对冠状病毒感染的防御作用进行了分析,旨在为更合理地利用不同来源和性质的低聚肽制备而成的复合肽类产品,更有效地增强人体免疫功能,为预防和治疗新型冠状病毒肺炎(COVID-19)提供营养支撑。     

一种狂犬病实验室诊断用单克隆抗体制备新路线的探索

目的 探索采用合成肽作为免疫原制备狂犬病实验室诊断用单克隆抗体的可行性.方法 以狂犬病病毒CVS-11核蛋白355-369位B细胞线性抗原表位合成肽与钥孔戚血蓝蛋白（Keyhole Limpe hemocyanin,KLH）大分子耦联后免疫BALB/c小鼠,利用经典杂交瘤细胞技术制备单克隆抗体.采用间接酶联免疫吸附试验（enzyme-linked immunosorbent assay,ELISA）和间接荧光试验（indirect fluorescent assay,IFA）筛选和鉴定杂交瘤细胞株.结果 经过对杂交瘤细胞株上清的间接ELISA和IFA筛选获得阳性杂交瘤细胞株2B1D11,该杂交瘤细胞株产生的抗体经纯化后在IFA中可以有效检出感染犬脑组织和BHK-21细胞的狂犬病病毒.结论 采用合成肽作为免疫原制备狂犬病实验室诊断用抗体在技术上是可行的.     

18F-RGD环肽二聚体的自动化合成及小动物PET显像

目的 应用国产多功能18F标记模块制备4-[18F]氟-3-三氟甲基苯甲酰基-谷氨酸-(RGD -苯丙氨酸-赖氨酸)环肽二聚体(4-18 F-TFMB-E[c(RGDfk)2]),并用micro PET观察其在肿瘤模型鼠内的生物分布.方法 基于PET-MF-2V-IT-I多功能合成模块,采用“一锅法”完成4-18F-TFMB-E[ c(RGDfk)2]的制备和纯化.荷人胰腺癌BxPC-3裸鼠给药后行micro PET活体显像.结果 4-18 F-TFMB-E[ c(RGDfk)2]放化产率为(27.4±2.3)％(衰减校正后),总合成时间为30 min,无需HPLC法分离,放化纯＞98％.荷人胰腺癌BxPC-3裸鼠注射4-18 F-TFMB-E[c(RGDfk)2]后30、60和120 min后肿瘤摄取值(％ID/g)分别为4.03±0.32、3.31±0.20和2.72±0.17;注射后30 min肿瘤与对侧肌肉摄取值比值大于6(对侧肌肉摄取值为0.47 ±0.12).4-18F-TFMB-E[c (RGDfk)2]主要经肝、肠排泄.结论 4-18F-TFMB-E[ c(RGDfk)2]自动化合成速度快、效率高,胰腺癌肿瘤模型显影清晰.     

三氧化二砷和尿多酸肽抗肝癌作用的协同效应

目的：探讨三氧化二砷（As2O3)和尿多酸肽诱导肝癌细胞凋亡的协同效应。方法：不同浓度的As2O3和尿多酸肽处理肝癌细胞株（BEL－7402，Hep G2)，用四唑蓝比色法检测细胞存活率；活细胞荧光染色观测细胞亡及形态学变化，流式细胞术分析细胞周期变化及凋亡率，并将不同剂量用于肝癌荷癌裸鼠，观察两药对荷癌鼠的作用，结果：As2O3诱导肝癌细胞凋亡的敏感剂量是5．0umol/L，而与尿多酸肽共同应用的凋亡敏感剂量是1．0umol/L As2O3 1.0g/L尿多酸肽。联合用药的实体型癌鼠皮下肿瘤生长的抑瘤率40．44％，较单用三氧化二砷的抑瘤率31．32％提高了近30％。结论：尿多酸肽可增加As2O3诱导肝癌细胞的凋亡效应，两药具有协同作用。     

Role of defensins in inflammatory lung disease

The human airways are protected from invading micro-organisms by the highly efficient innate immune system. Antimicrobial peptides that are produced by inflammatory cells and airway epithelial cells are key elements in this innate immune system. A major subgroup of the antimicrobial peptides is the family of defensins - small non-enzymatic and cationic peptides. Besides their extensively studied role in antimicrobial defense, recent studies have demonstrated that defensins are also able to modulate inflammatory responses, to stimulate adaptive immunity and contribute to tissue repair. In line with these observations, increased defensin levels were observed in inflammatory lung diseases, such as cystic fibrosis (CF), diffuse panbroncheolitis (DPB), idiopathic pulmonary fibrosis (IPF) and acute respiratory distress syndrome (ARDS), and in infectious diseases. In the past decade much has been learnt about the activity of defensins and there is abundant evidence for their presence in human inflammatory lung disease. Future studies are required to elucidate their role in the pathogenesis of these diseases.     

Dynorphin-(1–13)-Like Immunoreactivity in Central Nervous System and Pituitary Gland of Spontaneously Hypertensive Rats

We determined by radioimmunoassay concentrations of dynorphin-(1–13)-like immunoreactivity in the central nervous system and pituitary gland of spontaneously hypertensive rats (SHRs) and normotensive Wistar-Kyoto rats (WKYs). Compared to WKYs, SHRs had significantly lower levels of dynorphin-(1–13)-like immunoreactivity in the hypothalamus and pituitary gland. However, such immunoreactivity in the cerebral cortex, caudate nucleus, diencephalon, brainstem and spinal cord of SHRs and WKYs were similar.     

流式技术测定乙型肝炎患者外周血特异性CD8＋T细胞及其临床意义

目的 探讨流式细胞技术检测乙型肝炎患者HBV特异性CD8＋T细胞的水平并分析其临床意义.方法 采用HLA-A2分子胞外段与HBV核心表位肽core18-27结合的HLA-肽五聚体（Pentamers）对25例急性乙肝患者、35例慢性乙肝患者和10例正常健康人的外周血进行染色,设计流式细胞技术检测其针对该肽段的特异性CD8＋T细胞数量,以占总计数CD8＋细胞数的百分比表示.结果 12例HLA-A2＋的急性乙肝患者急性期可检测到高水平的特异性CD8＋T细胞,中位数为2.93%（1.12%～4.63%）,16例HLA-A2＋的慢性乙肝患者特异性CD8＋T细胞水平较低,中位数为0.75%（＜0.01%～1.76%）,两组之间差异有统计学意义（P＜0.01）.10例HLA-A2＋正常对照组、13例HLA-A2-急性乙肝对照组和19例HLA-A2慢性乙肝对照组的特异性CD8＋T细胞均不超过0.02%.结论 HLA-肽五聚体流式细胞技术能在体外直接检测HBV特异性的CD8＋T细胞数量,其水平可能影响着HBV感染者体内病毒的清除,且与乙肝的不同临床转归有关.     

Identification of insect-selective and mammal-selective toxins from Parabuthus leiosoma venom.

Venoms were collected from two scorpion species: Parabuthus leiosoma and Parabuthus pallidus from Kenya. Subcutaneous injection and oral toxicity tests of crude and pure fractions of scorpion venoms were done in Mus musculus (mice), Chilo partellus and Busseola fusca. The highest activity against C. partellus was found in P. leiosoma venom (LC(50) 0.689 mg/50mg body weight). Bioassay-guided purification by a combination of cation-exchange (CE) and reverse-phase high-performance liquid chromatography (RP-HPLC) led to the isolation of three toxic peptides. A lepidopteran-selective toxin (P. leiosoma insect toxin, Plit) was isolated, and the partial N-terminal amino acid sequence (-KDGYPVDNANCKYE-) plus the molecular weight (6688.5 Da) determined. A peptide with significant insect toxicity coupled with mild effects on mice (P. leiosoma toxin, Plt) was isolated, and the partial N-terminal amino acid sequence (-LCEKFKVQRLVELNCVD-) plus the molecular weight (6742.5 Da) was determined. Another toxin with anti-mammalian activity (P. leisoma mammal-selective toxin, Plmt), and N-terminal partial amino acid sequence of ADVPGNYPLDKNGNRYY- plus a molecular weight of 7145.5 Da was also isolated. Comparison of the partial N-terminal amino acid sequences with other toxins revealed that Plit shows high homology to other known insect toxins. Similarly, Plmt shows high homology with several birtoxin-like anti-mammalian toxins. Plt does not exhibit homology with any known scorpion toxin with combined anti-insect and anti-mammalian activity.     

Stability of some novel thymidine, 5-bromo-2'-deoxyuridine and 3'-azido-2'-3'-dideoxythymidine analogues

In the search of new prodrugs effective against herpes simplex virus series of thymidine, 5-bromo-2′-deoxyuridine esters with amino acid and peptide chains and 3′-azido-2′,3′-dideoxythymidine derivatives have been synthesized and evaluated for antiviral activity. The chemical stability of some of them containing different residues was studied at pH 1 and 7.4 and temperature of 37°C. An HPLC method was developed for quantification of the unchanged ester concentration. It was proved that esters with simple aliphatic straight side chain (containing alanyl-, glycyl-, or glycyl-glycyl-glycyl-residues) are relatively stable both at acidic and neutral media, 37°C. Some of them undergo negligible hydrolysis with half lifes ranging between 6 and 23 h. In contrast, more complex esters with branched side chain (valyl-), with phenyl residue (phenylalanyl-), as well as containing thiazol ring are rather unstable especially at acidic conditions and undergo rapid hydrolysis resulting in the respective chemical precursor. The stability of the former group esters outlines them as suitable candidates for prodrugs: with higher lipophilicity facilitating po absorption, satisfying chemical stability and possibility to release the active moiety following enzymatic hydrolysis.     

Parallel changes in behaviour and hippocampal monoamine metabolism in rats after administration of ACTH-analogues.

Application of footshock during the acquisition trial of a one-trial passive avoidance test is associated with a rise in the concentration of serotonin in the hippocampi of rats 24 hr after termination of the acquisition trial. Rats subjected to amnesic treatment with carbon dioxide (CO2) immediately after footshock do not show this rise in the hippocampal concentration of serotonin. The ACTH-analogues, ACTH 4-10 and ACTH 4-10 (7D-Phe), alleviate CO2-induced amnesia for the passive avoidance response when administered 1 hr before retrieval test 24 hr after acquisition. These peptides do not have anti-amnesic activity when given before acquistion. Another ACTH-analogue, ACTH 11-24 does not affect amnesia, given before either the acquisition or the retrieval test. The anti-amnesic effect of ACTH 4-10 AND ACTH 4-10 (7D-Phe), was correlated with a rise in the hippocampal serotonin concentration similar to that observed in non-amnesic animals. Pre-acquisition treatment with ACTH 4-10 or administration of ACTH 11-24 did not affect hippocampal serotonin concentrations. Changes in the hippocampal concentrations of noradrenaline, dopamine, tryptophan and tyrosine were not related to the behavioural activity of any of the peptides. It is suggested that alterations in hippocampal serotonin metabolism 24 hr after acquisition of a passive avoidance response are associated with the retrieveability of the passive avoidance response.