Genes encoded in the major histocompatibility complex affecting the generation of peptides for TAP transport

The B cell line 721.174 has lost the ability to present intracellular antigens to major histocompatibility complex (MHC) class I-restricted cytotoxic T lymphocytes (CTL). This phenotype results from a homozygous deletion in the MHC that includes the peptide transporter genes TAP1 and TAP2, and the proteasome subunits LMP2 and LMP7. Recent work has shown that such cells transfected with TAP genes load their class I molecules with endogenous peptides, and present several viral epitopes to class I-restricted CTL. These data implied that the LMP2 and LMP7 genes were not required for the presentation of most epitopes through class I molecules. By contrast, while confirming the previous reports, we have identified several epitopes that appear to require genes in the MHC in addition to the TAP for their presentation. Further analysis localizes the defect to proteolysis in the cytosol. In one case, presentation could be partially restored by re-expression of full-length LMP7. Control experiments with LMP7, from which the putative pro-region had been removed, failed to restore presentation, and this lack of effect correlated with failure of the shortened LMP7 to incorporate into the proteasome. These results suggest a role for LMP7 in the generation of a viral epitope, but leave open the possibility that additional genes within the .174 deletion are required for full restoration of antigen presentation.     

New high yield Cu(I) assisted 123I radioiodination of 15(p-I-phenyl)-9-methyl pentadecanoic acid,a potential myocardial tracer

A new high yield ¹²³I radioiodination (97%), based on the Cu(I) assisted isotopic exchange in an ethanol water mixture, of 15(p-I-phenyl)-9 methyl pentadecanoic acid, a potential myocardial tracer, is proposed. The method allows a true kit preparation of radioiodinated phenyl fatty acids for a substrate concentration of ±10^-6 moles. High specific activities (>0.1 mCi/g) can be obtained when coupling the labelling method to HPLC purification with an overall radiochemical yield of 75%.     

Roberts铜盐法测定蔗汁葡聚糖含量的热效应——淀粉对受热蔗汁葡聚糖测定的影响

作者从研究中发现:用Roberts铜盐法测定蔗汁样本葡聚糖含量时,所得结果与蔗汁的受热有关,受热蔗汁的测定值高于真实值,作者将这种现象暂称为Roberts铜盐法测定蔗汁样本葡聚糖含量的热效应。研究表明:蔗汁中的淀粉是引起热效应的重要因素。本文最后提出了一种由淀粉引起的热效应的可行校正方法。     

The hydroxylation, dechlorination, and glucuronidation of 4,4'-dichlorobiphenyl (4-DCB) by human hepatic microsomes

Since chlorine placement and the degree of chlorination of the biphenyl nucleus play an important role in the metabolism and ultimate elimination of polychlorinated biphenyls (PCBs), we have studied the metabolism of 4,4'-dichlorobiphenyl (4-DCB) by human hepatic microsomes. This low molecular weight PCB congener is substituted at the preferred site of metabolism (para-position). 4-DCB was metabolized by human microsomes with a Km of 0.43 microM and a Vmax of 1.2 pmoles/mg microsomal protein/min. Six metabolites were identified: 4,4'-dichloro-3,3'-biphenyldiol, 4'-chloro-3-biphenylol, 4'-chloro-4-biphenylol, 4,4'-dichloro-2-biphenylol, 4,4'-dichloro-3-biphenylol (most abundant), and 3,4'-dichloro-4-biphenylol. [14C]-4-DCB equivalents were found to covalently bind to microsomal protein. Addition of a 1 mM concentration of reduced glutathione decreased the degree of covalent binding. These data suggest that human microsomes metabolize this PCB through an arene oxide and that an "NIH shift" occurs. When UDPGA was added to the incubation, human microsomal glucuronosyltransferase catalyzed the formation of the glucuronide of the major metabolite, 4,4'-dichloro-3-biphenylol. These and previous in vitro results show that the biotransformation of PCBs by humans is governed by the same principles established for the in vivo biotransformation of PCBs by the rat, mouse and monkey. That is, PCBs without two adjacent unsubstituted carbon atoms are poorly metabolized and that an unsubstituted para-position facilitates metabolism.     

Dietary Habits,Selenium, Copper,Zinc and Total Antioxidant Status in Serum in Relation to Cognitive Functions of Patients with Alzheimer’s Disease

Oxidative stress plays a crucial role in the neurodegenerative process and can impair cognitive functions. In the prevention of Alzheimer’s disease (AD), an adequate consumption of dietary antioxidants may be a major factor. The objective of the study was to estimate selenium (Se), copper (Cu), zinc (Zn), and total antioxidant status (TAS) in the serum of patients with AD in relation to their cognitive functions and dietary habits. A total of 110 patients (aged 54–93 years) with early or moderate AD, as well as 60 healthy people (aged 52–83 years) were studied. The severity of the disease was assessed using the mini-mental state examination (MMSE) scale. Food-frequency questionnaires were implemented to collect the dietary data. The concentrations of Se, Cu and Zn in the sera were determined by the atomic absorption spectrometry method. TAS was estimated spectrophotometrically using ready-made kits (Randox). Significantly lower concentrations of Se, Zn and TAS, and higher Cu:Zn ratio in the serum of patients with AD, compared to healthy people, were observed. A low correlation between the MMSE score and TAS in the serum of AD patients and significantly higher MMSE values in patients with TAS above the reference range were also noted. In patients with serum Cu concentration above the norm, significantly lower MMSE values were found. Selected dietary habits such as the frequency of consumption of various food products had a significant impact on the concentration of the assessed parameters in the serum of people with AD.     

Human Diversity of Killer Cell Immunoglobulin-Like Receptors and Human Leukocyte Antigen Class I Alleles and Ebola Virus Disease Outcomes

We investigated the genetic profiles of killer cell immunoglobulin-like receptors (KIRs) in Ebola virus–infected patients. We studied the relationship between KIR–human leukocyte antigen (HLA) combinations and the clinical outcomes of patients with Ebola virus disease (EVD). We genotyped KIRs and HLA class I alleles using DNA from uninfected controls, EVD survivors, and persons who died of EVD. The activating 2DS4–003 and inhibitory 2DL5 genes were significantly more common among persons who died of EVD; 2DL2 was more common among survivors. We used logistic regression analysis and Bayesian modeling to identify 2DL2, 2DL5, 2DS4–003, HLA-B-Bw4-Thr, and HLA-B-Bw4-Ile as probably having a significant relationship with disease outcome. Our findings highlight the importance of innate immune response against Ebola virus and show the association between KIRs and the clinical outcome of EVD.     

细胞间粘附分子—1^125I标记及其纯度、免疫活性的鉴定

目的：建立细胞间粘附分子－1（intracellular adhesion molecule-1 ICAM-1)^125I标记方法及鉴定其纯度和免疫活性。方法：用氯胺－T法标记ICAM－1,用Sephadex G-50柱层析分离,用纸层析法鉴定^125I-ICAM-1的纯度,放免法检测其免疫活性,结果：^125I-ICAM-1比活度为77．84uCi/ug蛋白,标记率为65．54％,^125I-Na的放化纯度为97．27％,^125I-ICAM-1能够与ICAM－1－Ab的最大结合为88．64％,并且随ICAM－1－Ab滴度的降低而增高。结论：成功建立^125I标记ICAM－1的方法,并且^125I-ICAM-1具有一定的免疫活性。     

大鼠心肌缺血再灌注时心肌细胞凋亡情况及缺血预处理对其影响

目的探讨缺血再灌注及缺血预处理对大鼠缺血再灌注心肌细胞凋亡的影响.方法制备大鼠缺血预处理(IP)、缺血再灌注损伤(I/R)模型,采用末端脱氧核苷酸转换酶介导的生物素平移缺口末端标记技术(TUNEL)检测心肌细胞凋亡情况;同时检测心肌梗死范围.结果I/R组细胞凋亡率(43.37±4.82%)高,IP组虽然也有一定的心肌细胞凋亡率(24.53±2.95%),但较I/R组明显降低(P＜0.001).IP组心肌梗死范围较I/R组明显减小.结论心肌缺血再灌注损伤可诱发或加重心肌细胞凋亡,IP能明显减少缺血再灌注诱导的心肌细胞凋亡的发生率,能明显减少心肌梗死范围,减轻缺血再灌注损伤;IP能减少心肌梗死范围、减轻缺血再灌注损伤的机理可能与其能明显减少心肌细胞凋亡有关.     

单纯疱疹病毒Ⅰ型在兔脑神经细胞中的形态与形态发生

研究单纯疱疹病毒Ⅰ(HSV-Ⅰ)在兔脑神经细胞(RNC)中的形态与形态发生。方法 用电子显微镜观察超薄切片,并拍照记录。结果RNC感染HSV-Ⅰ6h后,细胞核中即可见散在核衣壳,12h后细胞核和细胞质内均可见到,但以核内多见,24h后病毒量达高峰。胶质细胞内的核衣壳多于神经元,胶质细胞和神经元的细胞质内和胞外可见少量有包膜的完整病毒。病毒颗粒为圆形或椭圆形,核心直径38～54nm,核衣壳77～100hm,成熟病毒115～129nm。结论RNC对HSV-Ⅰ高度敏感,HSV-Ⅰ在兔脑神经元和胶质细胞中的形态发生有一定的差异。     

肾透明细胞癌和卵巢癌与HLAI类抗原关联性研究

目的 分析HLAI类抗原与肾透明细胞癌和卵巢癌的关联性。为确定与这些肿瘤的易感性和抵抗性有关的基因。并为寻找肿瘤特异性的抗原肽,开展肿瘤免疫诊断和治疗奠定基础。方法 实验采用微量淋巴细胞毒试验。分析82例肾透明细胞癌和21例卵巢癌患者外周血HLA-A抗原和-B抗原的抗原频率。结果 与肾透明细胞癌和卵巢癌关联的HLAI类完全不同,其中与肾透明细胞癌关联的位点大大多于卵巢癌的位点,有A9、A11、A28、BG15、B22、B27和B40;而与卵巢癌关联的HLAI类抗原位点只有A10、A36和B12,且卵巢癌关联A10抗原保持显著关联。结论 HLAI类抗原关联性研究显示,HLA-A10可能为卵巢癌提供抵抗性。