A comparison of random vs. chemotaxis-driven contacts of T cells with dendritic cells during repertoire scanning

Generating adaptive immunity after infection or immunization requires physical interactions within a lymph node (LN) T-zone between antigen-bearing dendritic cells (DCs) that arrive from peripheral tissues and rare cognate T cells entering via high endothelial venules (HEVs). This interaction results in activation of cognate T cells, expansion of that T cell lineage and their exit from the LN T-zone via efferent lymphatics (ELs). How antigen-specific T cells locate DCs within this complex environment is controversial, and both random T cell migration and chemotaxis have been proposed. We developed an agent-based computational model of a LN that captures many features of T cell and DC dynamics observed by two-photon microscopy. Our simulations matched in vivo two-photon microscopy data regarding T cell speed, short-term directional persistence of motion and cell motility. We also obtained in vivo data regarding density of T cells and DCs within a LN and matched our model environment to measurements of the distance from HEVs to ELs. We used our model to compare chemotaxis with random motion and showed that chemotaxis increased total number of T cell DC contacts, but decreased unique contacts, producing fewer activated T cells. Our results suggest that, within a LN T-zone, a random search strategy is optimal for a rare cognate T cell to find its DC match and maximize production of activated T cells.     

血管内皮生长因子-C与乳腺癌淋巴管生成和淋巴结转移的关系

目的探讨血管内皮生长因子-C与乳腺癌淋巴管生成和淋巴结转移的关系。方法免疫组化法检测21例乳腺增生组和68例乳腺浸润性导管癌组病灶组织内VEGF-C蛋白的表达,并用淋巴管内皮细胞特异性标志物D2-40标记肿瘤新生淋巴管,计数肿瘤淋巴管的密度（LVD）。结果乳腺浸润性导管癌组VEGF-C的表达和淋巴管的密度（LVD）都明显高于乳腺增生组（P〈0．01）;乳腺浸润性导管癌中VEGF-C阳性组中淋巴管的密度（11．32±5．78）与VEGF-C阴性组中的淋巴管密度（8．75±3．53）,差别有统计学意义（P〈0．01）;乳腺浸润性导管癌中VEGF-C蛋白的表达和淋巴管密度（LVD）都与有无腋窝淋巴结转移及淋巴结转移个数有关（P〈0．05）。结论VEGF-C在乳腺浸润性导管癌淋巴管的生成中起着重要的作用;VEGF-C的高表达和淋巴管密度（LVD）的升高是促进乳腺导管癌淋巴结转移的重要的影响因素。     

一例疑似黏膜病死亡麋鹿消化及主要免疫器官病理组织学观察

应用常规石蜡切片,H.E染色,对临床初步诊断为黏膜病的一例死亡麋鹿(Elaphodus davidianus)的消化系统及脾、淋巴结进行病理组织学观察。结果表明,消化道的病变主要在黏膜层,黏膜上皮细胞脱落、坏死,固有层内毛细血管充血,炎性细胞浸润;脾主要表现为急性败血型,红髓充血、出血严重,白髓几乎完全消失;淋巴结坏死严重,组织结构被破坏,界限不明显,仅见淋巴细胞弥漫性分布于整个淋巴结内。病理组织学观察为临床诊断提供了形态学依据。     

Nepmucin/CLM-9, an Ig domain-containing sialomucin in vascular endothelial cells, promotes lymphocyte transendothelial migration in vitro

Nepmucin/CLM-9 is an Ig domain-containing sialomucin expressed in vascular endothelial cells. Here we show that, like CD31, nepmucin was localized to interendothelial contacts and to vesicle-like structures along the cell border and underwent intracellular recycling. Functional analyses showed that nepmucin mediated homotypic and heterotypic cell adhesion via its Ig domain. Nepmucin-expressing endothelial cells showed enhanced lymphocyte transendothelial migration (TEM), which was abrogated by anti-nepmucin mAbs that block either homophilic or heterophilic binding. Notably, the mAbs that inhibited homophilic binding blocked TEM without affecting lymphocyte adhesion. These results suggest that endothelial nepmucin promotes lymphocyte TEM using multiple adhesion pathways.     

Experimental manipulations of afferent immune responses influence efferent immune responses to brain tumors

Tumors grow more readily in the brain than in the periphery, in part due to immune privilege. Differences in both afferent and efferent components of the immune response contribute to this lower level of responsiveness. On the afferent side, despite the lack of lymphatic vessels in the brain, antigens from brain arrive in lymph nodes and spleen by several routes, and the route taken may influence the type of response generated. Work with viruses and soluble antigens in mice has shown that the intracerebral location and the volume of the inoculation influence the strength of the cytotoxic T cell response. We examined whether these factors influence the T cell response against experimental brain tumors in mice. Placement of tumor cells in the cerebral ventricles instead of the parenchyma generated an immune response sufficient to increase survival time. A large volume of an intraparenchymal infusion of tumor cells caused spread of cells to the ventricles, and resulted in longer survival time relative to a small volume infusion. Infusion of the same dose of radiolabeled tumor cells in either a small volume or a large volume allowed tracking of potential tumor antigens to the periphery. Both modes of infusion resulted in similar levels of radioactivity in blood, spleen and kidney. Unexpectedly, cells infused intraparenchymally in a small volume, compared to a large volume, resulted in (1) more radioactivity in cervical lymph nodes (parotid and deep cervical lymph nodes), (2) a greater number of CD11b+/Gr1+ myeloid suppressor cells in the tumors, and (3) fewer CD8+ cells within the tumor mass. Consistent with these observations, providing a stronger afferent stimulus by giving a concurrent subcutaneous injection of the same tumor cells infused into the brain increased CD8+ T cell infiltration of the tumor in the brain. These results suggest that the immune response elicited by antigens that drain predominantly to the cervical lymph nodes may be less effective than responses elicited at other lymph nodes, perhaps due to immunosuppressive cells. Directing therapies to the optimal peripheral sites may improve immune responses against brain tumors.     

Enhanced lymph node retention of subcutaneously injected IgG1-PEG2000-liposomes through pentameric IgM antibody-mediated vesicular aggregation

An efficient strategy for enhancing the lymph node deposition of rapidly drained liposomes from the interstitial injection site is described. Subcutaneously injected small-sized immuno-poly(ethyleneglycol)-liposomes (immuno-PEG-liposomes), containing 10 mol% mPEG₃₅₀-phospholipid and 1 mol% PEG₂₀₀₀-phospholipid in their bilayer and where IgG1 is coupled to the distal end of PEG₂₀₀₀, not only drain rapidly from the interstitial spaces into the initial lymphatic system, but also accumulate efficiently among the lymph nodes draining the region when compared with non-PEG-bearing immunoliposomes where IgG is directly coupled to the phospholipid. Liposome deposition among the draining lymph nodes, however, was further enhanced dramatically following an adjacent subcutaneous injection of a pentameric IgM against the surface attached IgG molecules (IgM:IgG, 10:1) without compromising vesicle drainage from the interstitium. This is suggested to arise either as a result of formation of large immuno-aggregates within the lymphatic vessels with subsequent transport to and trapping among the regional lymph nodes and/or following IgM binding to Fc receptors of the lymph node sinus macrophages forming a platform for subsequent trapping of drained IgG-coupled liposomes. This lymph node targeting approach may be amenable for the design and surface engineering of any rapidly drained nanoparticulate system bearing peptides and proteins that can be aggregated with a desired monoclonal pentameric IgM.     

Anticytokinin Effect on Apical Dominance Release in in vitro Cultured Rosa Hybrida L.

Effects of two cytokinin antagonists - 2-chloro-4-cyclobutyl-amino-6-ethylamino-1,3,5-triazine and N-(4-pyridyl)-O-(4-chlorophenyl)carbamate - on bud break and outgrowth in single nodes from two Rosa hybrida cultivars differing in their apical dominance were studied. The compounds were applied at three different concentrations separately or in combination with benzyladenine. Cytokinin antagonists reduced the number of the sprouted buds in both cultivars at different extent. Their effect was strongly dependent on both concentration applied and culture period duration. The replacement of anticytokinins with benzyladenine in the medium resulted in overcoming of the bud break suppression. Both compounds significantly inhibited bud outgrowth as well.     

Direct whole plant regeneration of cowpea [Vigna unguiculata (L.) Walp] from cotyledonary node thin cell layer explants

A simple protocol was established for high frequency direct shoot regeneration of cowpea [Vigna unguiculata (L.) cv. EPACE-1]. Bud proliferation occurred at the cotyledonary nodes of cowpea seedlings three weeks after culture on a medium containing Murashige and Skoog salts (1962) and B5 vitamins (Gamborg et al. 1968) supplemented with TDZ. A 10 μmol/L TDZ pre-treatment, shoot tip removal and excision of longitudinal thin cell layers (TCL) at the level of the cotyledonary nodes with subsequent culture on a MSB5 medium supplemented with 1 μmol/L IBA and 1 μmol/L TDZ were the optimal conditions for maximum bud proliferation. Up to 32.5 regenerated shoot buds were produced per TCL. The regenerated plants (R₀) were true-to-type and successfully transferred to soil.     

Automated identification of diseases related to lymph system from lymphography data using artificial immune recognition system with fuzzy resource allocation mechanism (fuzzy-AIRS)

Artificial immune recognition system (AIRS) classification algorithm, which has an important place among classification algorithms in the field of artificial immune systems, has showed an effective and intriguing performance on the problems it was applied. AIRS was previously applied to some medical classification problems including breast cancer, Cleveland heart disease, diabetes and it obtained very satisfactory results. So, AIRS proved to be an efficient artificial intelligence technique in medical field. In this study, the resource allocation mechanism of AIRS was changed with a new one determined by fuzzy-logic. This system, named as fuzzy-AIRS was used as a classifier in the diagnosis of lymph diseases, which is of great importance in medicine. The classifications of lymph diseases dataset taken from University of California at Irvine (UCI) Machine Learning Repository were done using 10-fold cross-validation method. Reached classification accuracies were evaluated by comparing them with reported classifiers in UCI web site in addition to other systems that are applied to the related problems. Also, the obtained classification performances were compared with AIRS with regard to the classification accuracy, number of resources and classification time. While only AIRS algorithm obtained 83.138% classification accuracy, fuzzy-AIRS classified the lymph diseases dataset with 90.00% accuracy. For lymph diseases dataset, fuzzy-AIRS obtained the highest classification accuracy according to the UCI web site. Beside of this success, fuzzy-AIRS gained an important advantage over the AIRS by means of classification time. By reducing classification time as well as obtaining high classification accuracies in the applied datasets, fuzzy-AIRS classifier proved that it could be used as an effective classifier for medical problems.     

Near-infrared-fluorescence imaging of lymph nodes by using liposomally formulated indocyanine green derivatives

Liposomally formulated indocyanine green (LP-ICG) has drawn much attention as a highly sensitive near-infrared (NIR)-fluorescence probe for tumors or lymph nodes in vivo. We synthesized ICG derivatives tagged with alkyl chains (ICG-Cn), and we examined NIR-fluorescence imaging for lymph nodes in the lower extremities of mice by using liposomally formulated ICG-Cn (LP-ICG-Cn) as well as conventional liposomally formulated ICG (LP-ICG) and ICG. Analysis with a noninvasive preclinical NIR-fluorescence imaging system revealed that LP-ICG-Cn accumulates in only the popliteal lymph node 1 h after injection into the footpad, whereas LP-ICG and ICG accumulate in the popliteal lymph node and other organs like the liver. This result indicates that LP-ICG-Cn is a useful NIR-fluorescence probe for noninvasive in vivo bioimaging, especially for the sentinel lymph node.