Lack of L-selectin expression by cells transferring diabetes in NOD mice: insights into the mechanisms involved in diabetes prevention by Mel-14 antibody treatment

The process of mononuclear cell extravasation from the blood into the islets of Langerhans in nonobese diabetic (NOD) mice is dependent on the expression of a set of molecules, most of which remain to be defined. The observation that vascular addressins are expressed in inflamed islets raises the issue of the involvement of one of their ligands, L-selectin, in the pathogenesis of autoimmune diabetes. Treatment of NOD females with Mel-14, an antibody specific for L-selectin, reduced the spontaneous development of both insulitis and diabetes. Pretreatment of diabetic donors with Mel-14 decreased the capacity of their splenocytes to transfer the disease. However, the treatment of recipients had no effect on the transfer of diabetes by untreated diabetogenic splenocytes. To reconcile these apparently conflicting results, we fractionated spleen T cells from diabetic mice according to L-selectin expression. Diabetogenic cells were found only in the L-selectin subpopulation. Thus, diabetogenic cells in adult mice share phenotypic characteristics with activated/memory cells, and enter the pancreas using L-selectin-independent migratory pathways.     

中国湖北地区汉族人群L-选择素基因P213S多态性研究

目的:了解中国湖北地区汉族人群L-选择素基因第六外显子P213S多态性分布,并与其它地区的分布进行比较。方法:应用聚合酶链反应-限制性片段长度多态性(PCR-RFLP)技术,检测206名健康者L-选择素基因P213S多态性基因型和等位基因频率分布。结果:L-选择素各基因型频率分别为PP型(45.63%)、PS型(49.03%)和SS型(5.34%)。P、S等位基因频率分别为70.15%和29.85%,这种基因多态性分布无性别差异(P>0.05)。湖北地区汉族人群L-选择素基因型和等位基因频率分布与英国及日本人有显著性差异(P<0.05)。结论:湖北地区汉族人群中存在L-选择素基因多态性,与其它地区分布比较有明显的差异。     

L-selectin ligands in rat high endothelium: multivalent sialyl Lewis x glycans are high-affinity inhibitors of lymphocyte adhesion

Lymphocyte homing is initiated by their tethering to and rolling on the high endothelium and is followed by extravasation into the lymph nodes. We show here that glycosylated cell adhesion molecule-1 (GlyCAM-1), CD34, and sialyl Lewis x (sLex) are present on rat lymph node high endothelium analyzed by using monoclonal antibodies. α(1,3)fucosyltransferase VII (Fuc-TVII), the last enzyme involved in the synthesis of the sLex sequence is also expressed on the rat lymph node high endothelium. We have synthesized a family of sLex-decorated oligosaccharide structures and used them to inhibit lymphocyte binding to high endothelium in the Stamper-Woodruff assay. Monovalent sLex, branched di- and tetravalent sLex, as well as a linear tetravalent sLex significantly reduce lymphocyte binding to endothelium. The branched and linear forms of tetravalent sLex were clearly superior inhibitors of the L-selectin-dependent lymphocyte adhesion, with IC50 values in low nanomolar range. In contrast, the fucose-free analogs having the same charge and approximately the same size as the corresponding sLex glycans had no effect on lymphocyte binding and served as negative controls. Taken together, these data show the crucial importance of sLex in the endothelial ligands for L-selectin. Furthermore, we suggest that L-selectin acts as an oligomer on the lymphocyte surface as it binds multivalent sLex glycans.     

Changes in thymic export of L-selectin+ γδ and αβ T cells during fetal and postnatal development

We have used the technique of in situ intrathymic injection of fluorescein isothiocyanate to examine L-selectin expression on γδ and αβ T cells immediately after emigrating from the thymus of fetal and postnatal animals. We found that the percentage of L-selectin⁺ thymocytes exported per day decreased by half after birth and that the export of T cells from the thymus does not rely on expression of the peripheral lymph node homing receptor, L-selectin. Analysis of L-selectin on emigrant and mature T cell subsets revealed a remarkable heterogeneity of expression, both in terms of the numbers of cells expressing this molecule as well as the level of expression. γδ T cells, reportedly not having a propensity for homing to lymph nodes, not only contained the highest proportion of L-selectin⁺ cells, but also expressed far more of this molecule than either CD4⁺CD8^? or CD4^?CD8⁺ αβ T cells. Furthermore, those emigrant T cells expressing L-selectin are somewhat immature in their expression of this molecule. Subsequent maturation resulted in up-regulation of L-selectin on mature peripheral blood T cells, maturation that was clearly independent of extrinsic antigen. This antigen-independent post-thymic maturation appeared to occur as part of the normal progression from immature thymocyte to mature peripheral T cell in both fetal and postnatal animals.     

Differential patterns of circulating adhesion molecules in children with bronchial asthma and acute bronchiolitis

The object of the study was to assess the levels of circulating forms of the cellular adhesion molecules ICAM-I, VCAM-1, E-selectin, L-selectin and P-selectin in young children with asthma and acute bronchiolitis. Thirty-nine children aged 12 to 84 months with mild or moderate asthma were studied at admission for acute asthma (n = 15) or in a stable phase (n = 24). Ten of the children with acute asthma were seen again after one month. Twenty-two children aged 1 to 17 months with acute bronchiolitis and nine non-atopic controls were also included in the study. In children with acute asthma, the mean concentration of circulating soluble ICAM-1 (SICAM-I) was increased compared to children with stable asthma (mean 442 μg/l versus 363 μg/l; p < 0.001) and to controls (363 μg/l; p < 0.05). The levels of SICAM-1 remained high at follow up. In children with stable asthma, the mean serum concentration of soluble L-selectin (sL-selectin) (2080 μg/l) was significantly higher than in the controls (1664 μg/l; p < 0.05). The levels of circulating cellular adhesion molecules were similar in atopic and non-atopic asthmatics. Children with acute bronchiolitis had increased serum levels of soluble VCAM-1 (sVCAM-I) (1637 μg/l versus 1019 μg/l in the controls; p < 0.01) and sL-selectin (2041 μg/l versus 1664 μg/l in the controls; p < 0.05). There was no difference between the levels of circulating cellular adhesion molecules in children with respiratory syncytial virus (RSV) positive and RSV negative bronchiolitis. Soluble E-selectin (sE-se-lectin) and soluble P-selectin (sP-selectin) in serum were not significantly increased in any of the groups studied. In conclusion, our data suggest differential patterns of circulating cellular adhesion molecules in young children with acute asthma, stable asthma, and acute bronchiolitis, which may reflect differences in the underlying inflammatory processes in these obstructive pulmonary diseases.     

原发性增殖性肾炎β2整合素及L-选择素表达的研究

目的探讨原发增殖性肾小球肾炎(PGN)患者外周血β2整合素(CD11 a、CD11b)、L-选择素(CD62L)的表达,了解它们在PGN发病中的作用机制。方法采用流式细胞技术检测32例PGN患者外周血及肾组织CD11 a、CD11b、CD62L的表达情况,同时观察血胆固醇、低密度脂蛋白、纤维蛋白原、血粘度、血清白蛋白的变化。结果PGN患者外周血CD11 a、CD11b明显低于正常,而CD62L显著升高。CD11b降低程度与CD11 a相一致,且CD11b降低程度与CD62L呈负相关关系。肾组织CD11 a、CD11b表达明显增加,CD11 a增加水平与CD11b呈正相关关系,CD62L波动较大。结论PGN患者外周血及肾组织的β2整合素,L-选择素存在异常,提示CD11 a、CD11b、CD62L在PGN的发病中可能具有一定的作用。     

Polymorphonuclear Leukocytes Released from the Bone Marrow Preferentially Sequester in Lung Microvessels

Objective : A hallmark of the systemic response to an inflammatory stimulus is the release of polymorphonuclear leukocytes (PMNs) from the bone marrow. This study was designed to measure the release of PMNs from the bone marrow and to determine their sequestration in the lung after an intravenous injection of either endotoxin (n = 5) or saline (n = 5). Methods and Results : The thymidine analogue 5′-bromo-2-deoxyuridine (BrdU) was used to pulse label dividing PMNs in the bone marrow of rabbits (n = 13), and immunohistochemistry and morphometry were used to detect the release of BrdU-labeled PMNs into the circulation and to determine their sequestration in the lung. Endotoxin treatment caused a drop in the circulating PMN counts (3.3 ± 0.08 at baseline to 0.12 ± 0.02 × 10⁹/L at 1 hour after endotoxin), which was followed by a neutrophilia at 8 hours (6.3 ± 1.1 × 10⁹/L, p < 0.01), an increase in circulating band cells (0.12 ± 0.01 at baseline to 2.18 ± 0.4 × 1⁹/L at 8 hours, p < 0.001), and an increase in the percentage of BrdU-labeled PMNs (0.01% ± 0.004% at baseline to 26.1% ± 3.2% at 8 hours, p < 0.001). Endotoxemia caused an arteriovenous difference in BrdU-labeled PMNs across the lung (35.9% ± 2.9% versus 26.1% ± 3.1%, mixed venous versus arterial, p < 0.02). Morphometric studies showed that endotoxin caused sequestration of PMNs in the lung (2.2 ± 0.4 versus 1.0 ± 0.2 × 10¹⁰, endotoxin versus saline, p < 0.03) with preferential retention of BrdU-labeled PMNs (0.79 ± 0.21 versus 0.039 ± 0.016 × 10¹⁰, endotoxin versus saline, p < 0.05). The percentage of BrdU-labeled PMNs in the alveolocapillary walls was higher than in circulating blood (64.01% ± 4.3% versus 26.1% ± 3.2%, p < 0.01) in the endotoxin group. In vitro filtration of cells through 5-mm pore size filters showed that circulating BrdU-labeled PMNs, 8 hours after endotoxin, were preferentially retained in the filters (p < 0.01). Conclusions : We conclude that endotoxemia stimulates the bone marrow to release mature and immature PMNs. Compared to PMNs released from the bone marrow during normal turnover, these PMNs are less deformable and preferentially sequester in the lung microvessels.     

rhGH对老年多器官功能不全患者CD47、L-选择素及高级氧化蛋白产物表达的影响

目的观察重组人生长激素(rh GH)对老年多器官功能不全(MODSE)患者膜糖蛋白CD47、L-选择素及高级氧化蛋白产物(AOPPs)表达的影响。方法 66例MODSE患者随机均分为对照组(n=33,给予常规治疗)及治疗组(n=33,在常规治疗基础上加用rh GH)。所有患者均于治疗前及治疗后第3、14、28天取静脉血,流式细胞仪检测血清CD47阳性率,ELISA和分光光度计法检测L-选择素及AOPPs浓度,并观察两组患者APACHEⅢ评分的变化。结果与治疗前比较,对照组和治疗组的CD47阳性率增高,AOPPs浓度、L-选择素水平及APACHEⅢ评分降低,差异均有统计学意义(P<0.05)。与对照组比较,治疗组CD47阳性率增高(P<0.05),AOPPs浓度降低,L-选择素水平下降,APACHEⅢ评分降低,病死率降低,差异均有统计学意义(P<0.05)。治疗组内观察,与治疗后第3天比较,第14天CD47阳性率增高,AOPPs浓度降低,L-选择素水平下降,APACHEⅢ评分降低,差异均有统计学意义(P<0.05);与治疗后第14天比较,第28天CD47阳性率增高,AOPPs浓度降低,L-选择素水平下降,APACHEⅢ评分降低,差异均有统计学意义(P<0.05)。结论 rh GH可增强MODSE患者的免疫功能,减轻氧化应激及炎症反应,并可降低病死率。     

非小细胞肺癌中CCR7和CD62L表达及与淋巴结转移的关系

目的探讨CC趋化因子受体7(CCR7)和L-选择素(CD62L)在非小细胞肺癌(NSCLC)组织中的表达及其与淋巴结转移的关系。方法采用免疫组化法检测80份NSCLC癌组织和20份癌旁正常肺组织标本中CCR7和CD62L表达,比较二者在淋巴结转移者与无淋巴结转移者中的阳性表达率。结果 NSCLC癌组织中CCR7和CD62L表达阳性率均明显高于癌旁正常肺组织(P均<0.05),且CCR7表达与CD62L表达有明显相关性(P<0.05)。有淋巴结转移者CCR7和CD62L表达阳性率均明显高于无淋巴结转移者(P均<0.05)。结论 NSCLC癌组织中CCR7和CD62L表达均上调,二者可能共同参与了NSCLC的淋巴结转移过程。     

火把花根片对EAE大鼠模型VCAM-1和L-选择素的影响

目的探讨火把花根片对实验性自身免疫性脑脊髓炎(EAE)大鼠模型的治疗作用以及对VCAM-1和L-选择素的影响。方法模型组采用豚鼠髓鞘蛋白匀浆和福氏完全佐剂诱发大鼠急性EAE模型;治疗组在模型组基础上予以火把花根(300mg·kg-1·d-1,每日2次),观察动物表现并评分,HE染色和Loyez氏髓鞘染色观察病理和髓鞘改变,免疫组化技术测定脑和脊髓的VCAM-1和L-选择素(L-selectin)水平。结果治疗组未出现临床症状,VCAM-1为(2.13±0.99),L-selectin为(1.88±0.64),与模型组比较差异有统计学意义(P<0.05);脑和脊髓小血管周围炎症细胞浸润明显减少,髓鞘结构完整。结论火把花根片对EAE有治疗作用,其作用机制与抑制VCAM-1及L-selectin表达有关。