刀豆素蛋白A诱导小鼠肝纤维化模型的建立

目的　建立小鼠的肝纤维化模型。方法　 2 0只Balb c小鼠随机分 2组。实验组 (E组 )小鼠经尾静脉注射12 .5mg kg剂量的 1mol L刀豆素蛋白A(ConA) ,每周 1次 ,连续 6周 ;而对照组 (N组 )正常小鼠则相应地经尾静脉注射 2 5 0 μLPBS。每次注射ConA或PBS 2 4h后 ,经小鼠尾静脉取血检测ALT和AST。第 6次注射ConA一周后处死小鼠 ,取肝组织做HE染色及MassonTrichrome染色 ,显微镜下观察肝脏组织形态改变及胶原沉积情况。结果　与对照组比较 ,实验组小鼠的ALT和AST均明显升高 ,肝体积明显增大 ,表面不光滑 ,布满增生小结节。光镜下见肝组织结构紊乱 ,肝细胞坏死明显 ,有较多的淋巴细胞浸润。MassonTrichrome染色胶原明显增多。结论　反复静脉注射ConA可成功诱导建立小鼠肝纤维化模型。     

淫羊藿苷对ConA诱导的小鼠肝脏损伤保护机理的研究

目的:利用刀豆蛋白A(ConA)诱导建立小鼠肝炎模型,观察淫羊藿苷对该损伤模型保护作用的细胞免疫学和分子免疫学机制。方法:采用C57BL/6雄性小鼠,随机分为淫羊藿苷+ConA组、生理盐水+ConA组、淫羊藿苷+生理盐水组。小鼠尾静脉注射ConA,建立T细胞介导的免疫性肝脏损伤模型;采用转氨酶试剂盒测定各组小鼠血液中转氨酶含量;组织病理学观察实验小鼠肝脏组织和肝细胞坏死变化;采用ELISA试剂盒测定血清中炎性细胞因子IFN-γ、TNF-α含量;流式细胞术观察注射ConA后肝脏淋巴细胞的活化变化。结果:与ConA对照组相比,淫羊藿苷干预组小鼠血液中ALT和AST水平明显降低,P<0.01;IFN-γ、TNF-α含量明显降低,P<0.05;H&E染色可见淫羊藿苷干预组小鼠肝细胞核完整,未见炎性细胞的浸润,而ConA对照组小鼠肝细胞核固缩,部分核膜破裂,肝组织内有炎症细胞和红细胞浸润;流式细胞技术发现淫羊藿苷可明显延缓由ConA引起的肝脏NKT细胞的活化,减弱T细胞的浸润。结论:淫羊藿苷对ConA诱导的小鼠肝脏损伤有明显的保护作用,其机理可能与淫羊藿苷降低血液中IFN-γ、TNF-α表达及影响肝脏NKT细胞的活化有关。     

腹腔注射刀豆蛋白A诱导昆明小鼠肝纤维化模型的建立

目的 建立昆明小鼠肝纤维化模型.方法 48只昆明小鼠随机分组.实验组40只,腹腔注射20 mg/kg剂量的刀豆蛋白A(ConA),每周一次,共9次.对照组8只,每周一次腹腔注射PBS.所有小鼠在每次注射后24 h采血测ALT、AST.实验组分别于第6、7、8、9次注射后1周各处死8只小鼠,余8只第9周起停止注射,第13周处死.对照组第9次注射后1周处死.所有小鼠处死后取肝脏计算肝脏指数,并作病理检查.结果 实验组第8次注射后出现典型肝纤维化,停止刺激4周仍然有纤维化表现.结论 反复腹腔注射ConA可以建立昆明小鼠肝纤维化模型.     

全反式维甲酸对Th2极化的调节作用

为了研究全反式维甲酸(all-trans retinoic acid,ATRA)对Th细胞分化的影响和可能的机制,无菌分离BALB/c小鼠脾细胞后,用2.5μg/ml的ConA刺激脾细胞,在不同时间加入不同剂量的ATRA,72 h后收集细胞,用3H-TdR掺入法测淋巴细胞增殖活性,用RT-PCR方法检测在Th细胞分化中起作用的细胞因子的mRNA表达水平。结果ATRA呈剂量依赖抑制ConA诱导的淋巴细胞的活化,10~(-5)mol/L的ATRA对ConA诱导的淋巴细胞活化的抑制作用最强;此抑制作用与作用时间呈相关性,ConA活化淋巴细胞24 h后加入ATRA对淋巴细胞活化的抑制作用最显著,并且淋巴细胞的活化程度越低,ATRA对其的抑制作用越强。ATRA可增强经ConA活化的淋巴细胞Th2型细胞因子(IL-4、IL-6)mRNA的表达水平,而Th1型细胞因子(IFN-γ、TNF-α)mRNA的表达水平显著性降低(P<0.05)。上述结果表明ATRA总体上可抑制ConA刺激的淋巴细胞增殖活性,但却可增强,Th2细胞的分化。这一研究为Th细胞免疫偏离的基础与临床研究提供了依据。     

喜树碱对小鼠T淋巴细胞活化、增殖以及细胞周期的影响

目的： 研究喜树碱（CPT）对刀豆蛋白A(ConA)介导的小鼠T淋巴细胞体外活化、增殖及细胞周期的影响。方法：以ConA刺激小鼠T淋巴细胞，建立小鼠T淋巴细胞活化、增殖的模型，以不同浓度的CPT作用于该模型，流式细胞术检测T细胞早期活化标志CD69分子的表达；以活体染料羧基荧光素乙酰乙酸（CFDA-SE）染色流式细胞术分析CPT 在Con A刺激下小鼠淋巴细胞的增殖相关指数（PI）；以碘化丙啶染色流式细胞术分析细胞周期的分布情况。 结果： ConA作用6 h后流式细胞术分析显示CD69的表达率为（58.88±0.55）%，不同浓度的CPT组（10 nmol/L、20 nmol/L、50 nmol/L、100 nmol/L）CD69的表达率分别为（55.48±0.98）%、（54.67±1.05）%、（50.40±0.82）%、（42.47±1.32）%，均可明显抑制CD69的表达(P<0.01)；ConA刺激48 h后流式细胞术分析显示，不同浓度的 CPT 组（10 nmol/L、20 nmol/L、50 nmol/L、100 nmol/L）的增殖指数（PI）明显低于对照组(P<0.05)；细胞周期分析显示刺激48 h后不同浓度的CPT组（10 nmol/L、20 nmol/L、50 nmol/L、100 nmol/L）均出现明显的凋亡峰（apoptosis peak，AP），sub-G1期、G₀/G₁期细胞的比率明显高于ConA刺激组(P<0.01)。结论：CPT可明显抑制ConA刺激的T淋巴细胞的活化、增殖，同时使淋巴细胞阻滞于G₀/G₁期。     

橙皮素对小鼠T淋巴细胞体外活化与增殖的影响

目的:研究橙皮素(Hes)对小鼠T细胞体外活化和增殖的影响,并探讨其作用机制.方法:用ConA刺激小鼠淋巴结来源的淋巴细胞,以不同终浓度Hes与T细胞共培养,利用荧光标记抗体双染色结合流式细胞术(FCM),检测各药物浓度Hes对ConA诱导的小鼠T细胞表达早期活化抗原CD69的作用;以酶标仪结合MTT比色法检测Hes药物的细胞毒性和对ConA诱导的小鼠淋巴结来源的淋巴细胞增殖的影响;以羧基荧光素乙酰乙酸(CFDA-SE)染色结合FCM检测Hes对ConA诱导的小鼠T细胞增殖的作用,并应用ModFit软件分析其增殖指数(PI).结果:淋巴细胞的存活率说明0.2 mL/L DMSO和25～75 μmol/L范围内的Hes对小鼠T淋巴细胞无毒副作用;MTT法、CFDA-SE法、双抗体染色法检测Hes对ConA诱导的小鼠T淋巴细胞的增殖和活化结果均显示,终浓度为25、50、75 μmol/L的Hes对ConA诱导的小鼠T淋巴细胞的增殖和活化均有抑制作用且呈剂量依赖关系.结论:有望通过进一步的研究将Hes发展为免疫抑制药物.     

氯喹可加重Con A诱导的自身免疫性肝损伤

氯喹(chloroquine,CQ)可抑制免疫反应,偶用于类风湿性关节炎、系统性红斑狼疮等自身免疫性疾病的治疗,但氯喹对自身免疫性肝炎的影响目前尚不明确。本研究拟探讨CQ对小鼠自身免疫性肝损伤的影响及可能机制。小鼠尾静脉注射Con A建立小鼠肝损伤模型,1h后,腹腔注射CQ或等体积PBS。观察小鼠生存状况,在不同时间点收集血清和肝组织,采用赖氏法检测血清谷丙转氨酶(GPT)水平;ELISA方法检测血清细胞因子IFN-γ及TNF-α含量;HE染色观察肝脏病理损伤情况;免疫印迹检测小鼠肝脏自噬水平指标LC3-Ⅱ和P62。结果显示,Con A+CQ组小鼠血清中GPT水平显著高于Con A组,且病理切片染色显示Con A+CQ组肝脏损伤较Con A组更严重;Con A+CQ注射组小鼠的存活率明显低于仅注射Con A组(P0.0001);Con A+CQ组小鼠血清中炎性细胞因子IFN-γ和TNF-α的分泌高于Con A组;CQ可抑制Con A刺激诱导的小鼠肝脏自噬水平升高。氯喹可加重Con A诱导的自身免疫性肝损伤,其机制可能是通过抑制肝脏自噬水平从而加剧小鼠肝脏损伤。     

两种不同种属小鼠急性免疫性肝损伤模型的比较

目的 探讨刀豆蛋白A(ConA)引起两种不同种属小鼠急性免疫性肝损伤的剂量差异。方法 雄性BALB/C小鼠和雄性C57BL/6小鼠分别为36只和40只。BALB/C小鼠分为对照组和5个(5、10、15、20和25 mg/kg ConA)实验组,C57BL/6小鼠分为对照组和5个(5、7.5、10、12.5和15 mg/kg ConA)实验组,实验组尾静脉注射设定剂量ConA。禁食不禁水,16 h后摘眼球采血,并取肝、脾和胸腺组织称重计算脏器指数,病理学检测肝组织,比色法测定血清中天冬氨酸氨基转移酶(AST)、丙氨酸氨基转移酶(ALT)活性,ELISA检测血清中肿瘤坏死因子α(TNF-α)含量,并结合各组动物死亡率,以确定最佳ConA剂量。结果 在BALB/C小鼠中,25 mg/kg剂量ConA死亡2只;AST、ALT活性和TNF-α含量与ConA呈剂量依赖性升高(P<0.05);肝脏指数与ConA的剂量呈现正相关(P<0.05);脾脏指数在5 mg/kg时高于10和15 mg/kg,表现出先升高再降低再升高的趋势。在C57BL/6小鼠中,ConA剂量在10、12.5和15 ...     

原卟啉钠对急性肝损伤小鼠肝组织SOD、MDA的影响

 目的 探讨原卟啉钠对四氯化碳（CCl4）致急性肝损伤小鼠血清转氨酶和肝组织超氧化物歧化酶（SOD）、脂质过氧化产物丙二醛（MDA）的影响。方法 60只ICR小鼠随机分为正常对照组、CCl4模型组、联苯双酯组、原卟啉钠低、中、高剂量组。各治疗组每天灌胃给药及造模16h后,摘眼球取血测定血清中谷丙转氨酶（ALT）和谷草转氨酶（AST）活性,剖腹取肝测定肝脏SOD活力和MDA含量。结果 CCl4模型组小鼠血清ALT和AST活力分别为（1879±1219）、（2210±1585）U/L,与正常对照组比较,降低显著（P<0.01）;联苯双酯组、原卟啉钠低、中、高剂量组的SOD活力和MDA含量分别为（207.61±16.02）、（184.35±13.42）、（190.88±17.77）、（199.38±14.43）U/mgprot和（1.08±0.15）、（1.35±0.26）、（1.07±0.16）、（0.92±0.18）nmol/mgprot,与CCl4模型组比较,差异有统计学意义（P<0.05～P<0.01）。结论 原卟啉钠能有效阻止CCl4致急性肝损伤小鼠肝组织SOD活性降低,脂质过氧化产物MDA含量升高,具有一定的保肝降酶作用。     

环孢菌素A对小鼠T细胞活化影响的血清免疫药理学评价

目的　应用血清免疫药理学技术 ,探讨环孢菌素A(CsA)对T细胞体外活化的影响 ,以进一步揭示CsA免疫调节的分子机制 ,为临床用药提供理论依据。方法　分离小鼠淋巴结细胞 ,分别与CsA、5 %CsA血清预孵后 ,加入多克隆刺激剂继续培养共 2 4h。收获细胞 ,进行双色免疫荧光标记 ,以流式细胞术分析T细胞上CD6 9分子的表达情况。结果　在CsA和 5 %CsA血清作用下 ,ConA活化的T细胞CD6 9表达的百分率分别为 (2 4 15± 3 38) %和 (2 3 6 8±6 89) % ,与相应对照组 [分别为 (6 4 6 7± 5 88) %和 (6 4 35± 10 13) % ]相比较均有显著差异 (P <0 0 1) ;在CsA和5 %CsA血清作用下 ,PDB活化的T细胞CD6 9表达的百分率分别为 (78 86± 7 70 ) %和 (80 0 5± 9 91) % ,与相应对照组 [分别为 (84 79± 6 87) %和 (79 6 8± 4 17) % ]相比较均无显著差异 (P >0 0 5 )。结论　CsA(410nmol/L)和含CsA血清均可强烈抑制ConA刺激的T细胞活化 ,而对PDB刺激的T细胞活化无抑制效应。 5 %CsA血清与CsA单纯药物体外实验的结果相一致 ,在一定程度上反映了临床等效剂量下血清免疫药理技术的有效性与可行性     

Effect of concanavalin A and succinyl concanavalin A on cytomegalovirus replication in fibroblasts

Summary In order to investigate inhibition of viral replication, human embryonic fibroblasts infected with cytomegalovirus (CMV) were treated with 0 to 25 µg/ml concanavalin A (Con A) and 0 to 150 µg/ml succinylated Con A (S-Con A). Alterations in cellular morphology occurred by day 2 post infection (p. i.) in cultures treated with 10 µg/ml Con A and 25 µg/ml S-Con A. With increasing concentrations of Con A and S-Con A there was decreased virus production from day 4 p. i. to day 10 p. i. Increasing levels of Con A and S-Con A also reduced the number of cells in culture. When virus titres were corrected to take cell number into account, decreased CMV titres in Con A and S-Con A treated cells appeared mainly to reflect decreased cell numbers. In support of this finding, in comparison with untreated CMV-infected fibroblasts, viral DNA synthesis was reduced and acid phosphatase levels were increased in CMV-infected cells treated with Con A or S-Con A.With 6 Figures     

Insulinomimetic homology of concanavalin A

A striking peptide sequence and three dimensional conformational homology between a portion of insulin and the plant lectin concanavalin A is described. This amino acid sequence has been demonstrated to be essential to the bioactivity of the hormone insulin. The insulinomimetic activity of the plant lectin on hormone target cells coupled with the presence of an insulin-homologous sequence and conformation offers insight into the mechanism of insulin action.     

Reconstitution of immunocompetence in B cells by addition of concanavalin A or concanavalin A-treated thymus cells

The effect of soluble Concanavalin A (Con A) on the primary antibody response in vitro against sheep red cells (SRC) by mouse spleen cells was studied. Stimulation of normal spleen cells with Con A caused a slight increase of the background number of plaque-forming cells (PFC). Cultures stimulated with SRC did not show an increased PFC response after Con A treatment, except in experiments where the PFC response against SRC was rather low in the absence of Con A. Concentrations of Con A higher than 0·5 μg/ml were inhibitory to the immune response of SRC-treated cultures also early during the culture period. In contrast, T cell depleted spleen cultures, incapable by themselves to respond to SRC, were reconstituted by addition of Con A at concentrations of 0·5 μg/ml or more. Presumably, residual T cells were activated by Con A. Con A activated T cells could reconstitute the PFC response in T cell-deficient cultures. In contrast, it was not possible to obtain more than a marginal stimulation of the antibody response in cultures of spleen cells depleted of adherent cells by addition of soluble Con A or Con A-activated thymocytes.

The results suggest that Con A may stimulate the antibody response by activation of T cells, and support the concept that activated T cells can non-specifically stimulate the antibody response of B cells. Large numbers of activated T cells were inhibitory to the immune response and it is suggested that this phenomenon is analagous to antigenic competition. Furthermore, activated T cells do not seem capable of substituting for adherent cells in the primary immune response in vitro, suggesting that adherent cells are important for the functions of B cells.

     

Immunosuppressive activity of concanavalin A.

Daily intraperitoneal doses of concanavalin A (Con A) produced a dose-related inhibition of adjuvant-induced arthritis in rats. Con A was also effective on established arthritis, markedly relieving the disease after only three doses. The inhibitory effect of Con A was neutralised by pre-incubation with ovalbumin, although this treatment did not modify the delayed phlogistic action of Con A in rat paws.     

Cytotoxicity of concanavalin A-activated hamster lymphocytes

The ability of hamster lymphoid cells to become cytotoxic in vitro to xenogeneic human cells after stimulation with concanavalin A (ConA) was investigated by using the cell-mediated (51)Cr release test. Cytotoxicity developed by 12 to 16 hr with peak values acquired within 24 hr of stimulation with ConA. The cytotoxicity was found to be mediated by the lymphoid cells themselves rather than by soluble substances. Spleen cells were more efficient than lymph node cells in releasing radioactivity from human cells. The concentration of mitogen was found to be critical in the development of cytotoxicity. ConA concentrations of 12.5 mug or less per culture conferred upon the lymphoid cells the capacity to release (51)Cr from target cells whereas higher concentrations were ineffective and even inhibitory. The cell-mediated cytotoxicity could be reversed by methyl alpha-d-glucopyranoside, but only during the first 8 to 12 hr of stimulation. The lytic reaction did not require the presence of ConA.     

Adsorption of concanavalin a on human platelets

A physiological cell surface absorption system approach is investigated on human platelets utilizing mathematical modeling. Monodispersed washed platelets are freshly collected in an isotonic buffer as a suspension utilizing a gel filtration technique. Concanavalin A is used as a glycoprotein receptor adsorbate in the adsorption studies. Three mathematical models are proposed based on simple chemical equilibrium reactions between adsorbate and cell surface receptors in an effort to explain concanavalin A—platelet surface glycoprotein interaction. Model I assumes that all receptors are undergoing simultaneous surface reactions with the adsorbate and without correlation. Model II reflects a strong correlation between the receptors, when only one receptor is active and the second receptor(s) is nothing but the combination of first receptor-adsorbate complex. Model III assumes the presence of multiple receptors on the cell surface. Only when a specific fraction of the total number of one receptor have reacted, will the other receptor(s) initiate reaction with the adsorbate. The results suggest the existence of at least three major glycoprotein receptors interacting with the lectin, and having different equilibrium constants as indicated in the adsorption isotherm. Model III seems to support best the experimental data of concanavalin A interaction with platelet surface glycoproteins.     

Detection of avian macrophages with concanavalin a

The reactivities of peroxidase-labelled concanavalin A (con A: 20 jug/ ml) with sections from various avian lymphoid organs were compared. With chicken bursae, con A binding and subsequent differential staining detected a non-lymphoid leukocyte population distributed throughout the sections. A comparable population was not observed in sections from the gland of Harder. With free cells, con A at low concentrations was found to selectively bind to both macrophages and heterophils but not to lymphocytes. Flow cytometric analysis with fluorescein isothiocyanate-labelled con A . also confirmed this selective binding. Peroxidase-labelled con A was used to detect non-lymphoid leukocytes present in areas of metastasised tumours in tissues of quail-chicken hybrids. Such staining was not seen in comparable normal tissues. Evidence that the tumour-localised leukocytes were macrophages was shown by the reactivity of these cells with a monoclonal anti-chicken la antibody. It is concluded that con A binding can be used to identify tissue macrophages and may provide a useful diagnostic tool in birds.     

Allergenicity of concanavalin A in mice.

Concanavalin A (Con A) is a potent allergen in certain strains of mice and in particularly the H-2Kk mice, A/J, CBA/H, and C3H/He. Using a dose of 100 microgram, the subcutaneous route of injection was the most effective means of inducing high, persistent titers of T cell-dependent circulating anti-Con A reagins without the addition of the classical IgE adjuvants, aluminium hydroxide and Bordetella pertussis vaccine. Haptenated Con A induced reagins with antihapten specificity. In the discussion, one possible contributing factor in Con A allergenicity in genetically responder strains of mice is emphasised, namely, persistence in subcutaneous injection sites.