补体经典激活途径C3转化酶的体外组装及活性观察

目的：体外组装包含人C4分子的补体经典激活途径C3转化酶，并对其转化酶活性及衰变特性进行观察。方法：利用豚鼠血清功能纯C1、C2及溶血中间体EAC4^hu体外组装经典途径C3转化酶，观察不同C1、C2用量及孵育温度对C3转化酶形成和自发性衰变的影响，以及人红细胞膜抽提蛋白对C3转化酶衰变化的影响。结果：高剂量和低剂量的C1均会影响C3转化酶的形成，增加C2用量可增加C3转化酶的形成数量，C3转化酶的自发性衰变随孵育温度的升高而加速，人红细胞膜抽提蛋白可抑制C3转化酶的自发性衰变过程，结论：C1、C2用量及孵育温度是影响C3转化酶形成和自发性衰变的主要因素，体外组装的补体经典激活途径C3转化酶可应用于相关补体调控蛋白的活性检测。     

A new family with epiphyseal chondrodysplasia type Miura

Epiphyseal chondrodysplasia, Miura type (ECDM) is a skeletal dysplasia with tall stature and distinctive skeletal features caused by heterozygous NPR2 pathogenic variants. Only four families have been reported. We present a family with five affected individuals (mother, three sons, and daughter). The mother's phenotype was relatively mild: borderline tall stature and elongated halluces operated during childhood. The children were remarkably more severely affected with tall stature, scoliosis, and elongated toes and fingers leading to suspicion of Marfan syndrome. Progressive valgus deformities (at the hips, knees, and ankles) were the main complaints and necessitated orthopedic investigations and surgery. Radiographs showed coxa valga, scoliosis, multiple pseudoepiphyses of the fingers and toes with uneven elongation of the digits and ankle valgus. The two older brothers underwent osteotomies and guided growth for axial deformities and arthrodesis for elongated halluces. Genetic testing confirmed the clinical diagnosis of ECDM: all affected individuals had a heterozygous c.2647G>A (p.Val883Met) NPR2 variant in a highly conserved region in the carboxyl‐terminal guanylyl cyclase domain. This two‐generation family elucidates the clinical and radiological variability of the disease. These rare cases are important to gain further understanding of the fundamental processes of growth regulation.     

喉癌细胞中S100A8新的相互作用蛋白质的鉴定

目的探索S100A8相互作用蛋白在喉癌发生、发展中的可能机制。方法应用抗S100A8抗体通过免疫沉淀的方法从喉癌细胞系Hep-2中分离与S100A8相互作用的蛋白质。用基质辅助激光解析电离飞行时间质谱仪分析目的蛋白条带。根据这些目的蛋白条带的肽指纹谱,用Mascot软件预测其相应的蛋白质。用P-Match软件预测这些蛋白质的NF-kappa B结合位点。用免疫共沉淀方法证实其中一个蛋白质与S100A8相互结合的能力。结果获得了4种与S100A8相互作用的新的蛋白质,它们分别是假想蛋白质LOC80154（hypothetical protein LOC80154）、MHCclass Ⅰ HLA-B、T-box1异构体C相似蛋白质（similar to T-box1 isoformC）和肌纤维膜相关蛋白1（sarcolemmal associated protein 1）。这4种蛋白质均具有NF-kappa B的结合位点,其中MHCclass Ⅰ HLA-B是NF-kappa B通路中的一个成员,我们首次证实该蛋白质具有结合S100A8的能力。结论本研究获得的S100A8新的伴侣可能是NF-kappa B通路的成员。MHCclass Ⅰ HLA-B与S100A8的结合提示S100A8可能作为新成员与包括HLA-B在内的其他蛋白质在NF-kappa B通路中发挥作用。这些发现为进一步研究S100A8在喉癌发生中的分子机制提供了新线索。     

Ca2+ permeability of the plasma membrane induced by rotavirus infection in cultured cells is inhibited by tunicamycin and brefeldin A

Rotavirus infection of cultured cells induces a progressive increase in plasma membrane permeability to Ca2+. The viral product responsible for this effect is not known. We have used tunicamycin and brefeldin A to prevent glycosylation and membrane traffic and study the involvement of viral glycoproteins, NSP4 and/or VP7, in rotavirus-infected HT29 and MA104 cells. In infected cells, we observed an increase of plasma membrane Ca2+ permeability and a progressive depletion of agonist-releasable ER pools measured with fura 2 and an enhancement of total Ca2+ content measured as 45Ca2+ uptake. Tunicamycin inhibited the increase in membrane Ca2+ permeability, induced a depletion of agonist-releasable and 45Ca2+-sequestered pools. Brefeldin A inhibited the increase of Ca2+ permeability and the increase in 45Ca2+ uptake induced by infection. We propose that the glycosylated viral product NSP4 (and/or VP7) travels to the plasma membrane to form a Ca2+ channel and hence elevate Ca2+ permeability.     

Further studies on the aberrant crossed visual corticotectal pathway in rats

Summary An aberrant crossed corticotectal pathway can be generated by removal of one visual cortex and the contralateral superior colliculus from newborn rats. This aberrant crossed corticotectal projection arises from the pyramidal neurons located in layer V of the visual cortex and terminates in a spatially orderly manner in the appropriate laminae of the cortically deafferented contralateral colliculus. Comparable results cannot be reproduced by unilateral collicular lesions alone. The significance of these findings and the possible mechanisms involved in the formation of the aberrant pathway are discussed and compared with the retinotectal system.The research was supported by USPHS Grant EY-00596 from the National Institutes of Health     

基因芯片对大鼠肝移植急性排斥反应T淋巴细胞信号传导基因表达变化的研究

目的：从基因水平研究肝移植急性排斥反应中T淋巴细胞信号传导途径。方法：利用4096条大鼠cDNA克隆的基因芯片对从急性排斥组Wistar→SD(n=5)和对照组SD→SD(n=5)两组肝移植大鼠T细胞中抽提、纯化mRNA，扩增、逆转录成cDNA，荧光标记后与芯片杂交，扫描后筛选出差异表达的基因。结果：在4096个基因中共发现差异表达基因190条，其中ll条与细胞信号传导有关的基因差异表达明显：MHC(3条)、CD3抗原(1条)相关基因；蛋白酶类：蛋白激酶C结合蛋白、蛋白酪氨酸磷酸酯酶D型受体、磷脂酰肌醇二磷酸酶基因各l条；涉及核酸信号传导、激活、转录、翻译的基因3条。结论：T细胞在肝移植术后排斥反应中信号传导机制涉及多个基因，基因芯片技术的大规模筛选为进一步研究T细胞在排斥反应中的信号传导途径提供了客观依据和目标。     

Dissecting natural killer cell activation pathways through analysis of genetic mutations in human and mouse

Summary:  Natural killer (NK) cell cytotoxicity is mediated by multiple germ line-encoded activating receptors that recognize specific ligands expressed by tumor cells and virally infected cells. These activating receptors are opposed by NK inhibitory receptors, which recognize major histocompatibility complex class I molecules on potential targets, raising the threshold for NK cell activation. Once an abnormal cell has been detected, NK cells are the sentinel source of cytolytic mediators, such as granzymes and perforins, as well as interferon-γ, which can polarize the immune response to a T-helper 1 cell type. Activation signals are transmitted by adhesion-dependent pathways, immunoreceptor tyrosine-based activation motif (ITAM)-dependent pathways, DAP10 ITAM-independent pathways, and by signaling through immunoreceptor tyrosine-based switch motifs. These pathways activate downstream signaling partners to trigger NK cell cytotoxicity. Some of these downstream molecules are unique to the various pathways, and some of these molecules are shared. Because of the complexity of signals involved in NK cell–target cell interaction, the generation of mice with targeted mutations in signaling molecules involved in adhesion, activation, or inhibition is essential for a precise dissection of the mechanisms regulating NK cell effector functions. Here we review recent advances in the genetic analysis of the signaling pathways that mediate NK cell killing.     

NOD小鼠胸腺细胞TCR介导的信号通路缺陷

目的 进一步研究NOD小鼠T细胞应答改变机理。方法 用抗TCR抗体、ConA激活NOD小鼠胸腺细胞，分析TCR介导的信号通路的水平。结果 与Balb／c小鼠胸腺细胞相比，抗TCR抗体诱导的增殖应答较弱，与年龄及NOD胸腺CD4^ CD8^-和CD4^-CD8^ SP细胞有关；rIL-2能部分恢复对TCR抗体应答的缺乏。NOD小鼠对PMA IONO和PMA anti—TCR-mAb应答正常，但对anti-TCRmAb IONO应答缺乏。结论 与年龄有关的NOD小鼠胸腺细胞对TCR抗体应答的缺乏与T细胞激活时上游PKC信号通路的缺乏有关。     

Antibodies against rabbit red blood cells in murine serum and their effect on the activity of complement alternative pathway

Antibody content against rabbit red blood cells (anti-RaRBC) in murine sera of different strains (Swiss, CBA, C57BL/6, AKR, BALB/c) and activity of complement alternative pathway (AP) were investigated. In contrast to the CBA and C57BL/6, random-bred Swiss strain and inbred BALB/c and AKR strains are good producers of these natural antibodies. There is no correlation between AP activity and anti-RaRBC content. Isolated human anti-RaRBC antibodies, IgM and IgG classes, lead to the enhancement of APhu and APmo activity, contrary to the murine anti-RaRBC which belong solely to IgM class, and do not express this capability.