在大剂量5-氟尿嘧啶治愈荷瘤小鼠过程中外周血细胞的变化与肿瘤消退之间的相关性分析

目的:观察在单一剂量5-氟尿嘧啶(5-FU)治愈荷瘤小鼠过程中外周血细胞数量的变化与肿瘤结节缩小之间的关系,为进一步研究化疗治愈肿瘤的作用机制奠定基础.方法:利用单一剂量5-FU治愈荷瘤野生型C57BL/6小鼠模型,荷瘤小鼠腹腔内分别注入25、75、135 mg/kg的5-FU,等量生理盐水对照,确定5-FU治愈肿瘤的量效关系.然后,再取6只荷瘤小鼠,分别在75 mg/kg 5-FU治疗前3 d、治疗后第1、4、7、11、15、28天内眦静脉取血,进行血常规检测,分析外周血白细胞、血红蛋白和血小板的变化与荷瘤小鼠肿瘤结节缩小之间的相关性.结果:75、135 mg/kg的5-FU均可使荷瘤小鼠的肿瘤结节在治疗后1周内逐渐缩小、直至消退,因此5-FU治愈荷瘤小鼠的最低有效量为75 mg/kg.75 mg/kg 5-FU治疗后第1天外周血白细胞降为(5.0±1.1)×109/L,并持续到化疗后第4天,与治疗前(9.5±1.58)×109/L比较差异有统计学意义(P<0.01);5-FU治疗后第7 ～15天外周血白细胞的数量升至化疗前水平,随后逐渐下降,在治疗后第28天降至(5.9±1.96)×109/L,低于化疗前水平(P<0.01).Hb含量在5-FU治疗后第1天也出现降低,由化疗前的(133±7) g/L降为(112±9) g/L,差异有统计学意义(P<0.01),随后Hb含量持续在低水平,治疗后15 d 逐渐恢复至化疗前水平.75 mg/kg的5-FU对荷瘤小鼠血小板的抑制作用不明显,反而在治疗后第1、11天出现2次血小板一过性增高(P<0.01).结论:75 mg/kg 5-FU可引起外周血白细胞数和血红蛋白浓度的降低,但对血小板的抑制作用不明显.5-FU发挥抗肿瘤作用使荷瘤小鼠的肿瘤结节缩小与化疗后外周血白细胞和Hb的降低无关,而与化疗后第1天血小板计数的增加有关.     

红花多糖对荷瘤小鼠肿瘤组织血管生成的抑制作用研究

目的 观察红花多糖(SPS)对荷S180小鼠肿瘤组织血管生成的抑制作用.方法 按照SPS低剂量组20 mg/kg·d、SPS中剂量组40mg/kg·d、SPS高剂量组80 mg/kg·d的剂量对荷瘤小鼠进行腹腔注射给药,模型对照组给等体积的生理盐水,连续10天,第11天取瘤组织,免疫组化法检测肿瘤组织中血管内皮生长因子(VEGF)含量及微血管密度(MVD).结果 免疫组化法检测显示,SPS干预后小鼠肿瘤组织中VEGF灰度值上升:模型组(143.9±13.60)、SPS低剂量组(157.1±9.57)、SPS中剂量组(166.4±8.93)和SPS高剂量组(168.8±10.13);mVD明显下降:模型组(41.25±3.58)、SPS低剂量组(38.75±3.69)、SPS中剂量组(31.88±3.00),SPS高剂量组(25.38 ±4.21).结论 SPS能够通过抑制VEGF的表达、降低MVD,使肿瘤生长及转移受到抑制.     

应用环磷酰胺构建C57BL/6J小鼠免疫抑制模型

背景：在免疫增强剂的研究中,常用到免疫抑制模型,如何建立免疫抑制模型成为免疫增强剂作用评价的关键。 目的：应用环磷酰胺构建C57BL/6J小鼠免疫抑制模型。 方法：将小鼠随机分为正常对照组、环磷酰胺50 mg/kg 5 d组,环磷酰胺80 mg/kg 3 d组,环磷酰胺80 mg/kg 5 d组,环磷酰胺100 mg/kg 5 d组和环磷酰胺100 mg/kg隔天给药组。正常对照组小鼠腹腔注射生理盐水0.1 mL,连续5 d。环磷酰胺50 mg/kg 5 d组,环磷酰胺80 mg/kg 3 d组,环磷酰胺80 mg/kg 5 d组和环磷酰胺100 mg/kg 5 d组小鼠分别以环磷酰胺50,80,80,100 mg/kg腹腔注射连续5,3,5,5 d。环磷酰胺100 mg/kg隔天给药组小鼠腹腔注射100 mg/kg环磷酰胺,隔天1次,共注射3次。 结果与结论：与正常对照组比较,腹腔注射环磷酰胺可导致小鼠外周血中CD3⁺T,CD3⁺CD4⁺T及CD3⁺CD8⁺T细胞明显下降(P < 0. 05);谷丙转氨酶(除环磷酰胺50 mg/kg 5 d、80 mg/kg 3 d组)、谷草转氨酶、尿素显著升高(P < 0.05),其中环磷酰胺80 mg/kg 5 d组、环磷酰胺100 mg/kg 5 d组和环磷酰胺100 mg/kg隔天给药组对肝肾功能的影响更为明显。提示腹腔注射环磷酰胺可建立CD3⁺T,CD3⁺CD4⁺T及CD3⁺CD8⁺T细胞明显下降的免疫抑制模型,其中以环磷酰胺50 mg/kg 5 d和80 mg/kg 3 d方式对肝肾功能的损伤较小。     

供体血管内皮细胞对小鼠-大鼠移植心脏存活时间的影响

目的 探讨供体血管内皮细胞对小鼠-大鼠移植心脏存活时间的影响.方法 分离小鼠血管内皮细胞并于移植前14 d注入大鼠阴茎背静脉2×106细胞/只或联合注射环磷酰胺20 mg/kg·d.异位小鼠-大鼠心脏移植后观察供心存活时间. 结果 成功分离小鼠血管内皮细胞,注射小鼠血管内皮细胞14 d后,移植心脏平均存活时间(10±1.414)min, 组化染色显示供心有IgM、C3沉积,血浆IgM、IgG、C3、C4较未注射血管内皮细胞组明显增高;联合使用环磷酰胺能延长供心成活时间(19.44±2.603 4)min(t=2.880,P ＜ 0.01).结论 外周静脉注射供体血管内皮细胞不能诱导延迟性异种移植排斥反应(DXR)的免疫耐受,却促使发生HAR.联合环磷酰胺可延长供心存活时间.     

消炎痛对醋氨酚所致小鼠肝脏损伤的保护作用

消炎痛预处理对醋氨酚所致小鼠肝损伤有明显的保护作用。300mg/kg剂量的醋氨酚引起严重的肝损伤,如果在给醋氨酚前24小时皮下一次注射消炎痛(10mg/kg),则损伤明显减轻。经消炎痛预处理动物的SGPT由对照的组1666±43下降到554±153 u/100ml,组织学检查也明显减轻,500mg/kg剂量的醋氨酚引起的死亡率由90％降到45％。小鼠经苯巴比妥钠(80mg/kg)处理三天,以增加细胞色素P_(450)含量,此时醋氨酚引起的肝损伤加重,且由消炎痛诱导的肝保护作用被消除。     

DEN-2 NGC株感染BALB/c小鼠TH1/TH2类细胞因子产生的差异

目的通过观察2型登革病毒(DEN2)NGC株初次感染和再次感染BALB/c小鼠后小鼠血浆中TH1和TH2类细胞因子的产生及其动态变化,研究DEN2感染的免疫机制。方法用不同量的DEN2NGC株经皮下多点注射,建立BALB/c小鼠感染模型,间接ELISA法测定感染后不同时间小鼠血浆IL-2、IFN-γ、IL-4、IL-5、IL-6、IL-10的含量。结果(1)在初、再次感染阶段,DEN2NGC株各感染组产生IL-4、IFN-γ、IL-2、IL-5、IL-6、IL-10与正常对照组有显著差异(P<0·05)。①在初次感染阶段,NGC株各感染组血浆IL-2、IL-5、IL-6于第4、6、8天出现;在再次感染阶段,各感染组产生IL-2、IL-5、IL-6均于第1天迅速升高;IL-2水平于第4天达高峰(104448·46±13314·1pg/ml),维持5~7天后迅速下降;IL-5于48小时达到高峰(135·125±46·75pg/ml);各组小鼠IL-6产生的动态相似,在再次感染后第1天,达高峰(555·823±44·639pg/ml)后逐渐下降。②初次感染早期,IL-4水平明显升高,而IFN-γ处于较低水平;再次感染后第1天,IL-4水平达最高峰(4294·668±349·038pg/ml),IFN-γ则于第4天和第11天达较高水平,两者的产生彼消此长,且产生动态与感染病毒量有关。(2)在初、再次感染阶段,用不同量DEN2NGC株感染组产生细胞因子水平有差异。结论DEN2NGC株初次和再次感染BALB/c小鼠后,TH1和TH2应答均可发挥一定作用,二者相互影响,TH细胞及其产生的CK在DEN感染的发病机制中起重要作用。     

体内表达谷胱甘肽过氧化物酶-7基因对骨髓抑制的防护作用研究

目的 探讨体内表达谷胱甘肽过氧化物酶-7基因(Gpx-7)对5-氟尿嘧啶(5-Fu)引发小鼠骨髓抑制的防护作用.方法 以尾静脉注射5.Fu(250 mg/kg)的方法建立小鼠骨髓抑制和再生模型.5-Fu注射后第1天,通过电穿孔转染法将pcDNA3.1-Gpx7重组质粒50 μg注入小鼠胫前肌(实验组),以pcDNA3.1空质粒载体50μg电穿孔转染作为对照组,每组各30只小鼠.5-Fu注射前和注射后3、7、11、14 d,2组各断颈处死6只小鼠,计数小鼠外周血白细胞数、血小板数和单条腿骨髓细胞总数;然后分别取5-Fu注射后7、14 d断颈处死小鼠各3只进行骨髓细胞集落形成试验;并分别取5-Fu注射前和注射后3、7、11、14d断颈处死的小鼠各1只制备完整大腿骨石蜡组织切片,观察骨髓组织形态学的变化.结果 注射5-Fu后11和14 d,实验组外周血白细胞数分别为(3917±733)和(6857±1878)/μl,均明显高于同时点对照组[分别为(2683±920)和(4017±1011)/μl,均P<0.05)];注射5-Fu后11 d,实验组外周血小板数为(150.8±64.3)万/μl,明显高于同时点对照组[(63.0±60.3)万/μl,P<0.05)];注射5-Fu后不同时间2组间单条腿骨髓细胞总数差异无统计学意义.注射5-Fu后7、14 d,2组之间骨髓细胞集落形成数差异无统计学意义.实验组注射5-Fu后11 d小鼠的骨髓组织形态恢复程度与对照组注射5-Fu后14 d小鼠类似:注射5-Fu后14 d小鼠的骨髓组织形态接近注射前.结论 体内表达Gpx-7基因可以促进被化疗药物5-Fu抑制的小鼠骨髓再生.     

头孢地秦在免疫抑制小鼠白念珠菌败血症中的作用

为观察头孢地秦 (cefodizime ,CDZ )在实验性免疫抑制小鼠白念珠菌败血症中的免疫调节作用及其在抗感染免疫中的综合作用 ,本文用环磷酰胺 (CTX )免疫抑制昆明种小鼠 ,分别腹腔注射CDZ 6 0 0mg/kg、 2 0 0mg/kg、 5 0mg/kg及头孢曲松 (cef triaxone ,CRO ) 2 0 0mg/kg× 7d。并在第 3天尾静脉注射白念珠菌 ,第 8天分别测定各组的炭廓清功能、血清溶血素的生成及T细胞亚群的变化。观察小鼠注射白念珠菌后的生存期并作生存分析。研究表明CDZ 6 0 0mg/kg、CDZ 2 0 0mg/kg组能明显提高CTX抑制的炭廓清功能 (P <0 0 5 ) ;CDZ各组亦能增加被CTX抑制的血清溶血素水平 (P <0 0 1) ;与CTX组相比 ,CDZ6 0 0mg/kg组明显提高CD4/CD8比值 (P <0 0 5 )。整体比较各组生存率 ,与其免疫调节功能基本一致。尾静脉注射白念珠菌后 ,CTX组 3d就有小鼠死亡 ,其平均生存期为 5d ,而CDZ 6 0 0mg/kg组、 2 0 0mg/kg组、 5 0mg/kg组最长生存期分别为 16d、17d和 12d ,其平均生存期分别为 12 8d、 11 7d和 9 6d ,明显高于免疫抑制组小鼠 (P <0 0 1)。而CRO组和免疫抑制组相比 ,差别无显著差异。说明CDZ能提高免疫抑制机体的免疫功能 ,并在抗感染免疫中发挥作用 ,提示其在临床感染治疗上可能具有重要的实际意义。     

小剂量美法仑治愈荷瘤小鼠过程中外周血细胞计数的变化及其意义

目的: 观察在小剂量美法仑治愈荷瘤C57BL/6小鼠过程中外周血细胞计数的变化与肿瘤结节缩小之间的关系, 为进一步研究化疗治愈肿瘤的作用机制奠定基础.方法: 野生型C57BL/6小鼠皮下接种小鼠淋巴瘤EL4 细胞, 建立荷EL4 肿瘤的小鼠模型.肿瘤接种后12 d, 12只荷瘤小鼠随机分成2组, 7.5 mg/kg美法仑单次腹腔内注射, 等量生理盐水对照.观察荷瘤小鼠肿瘤结节直径的变化.用药组小鼠分别在7.5 mg/kg美法仑治疗前3 d、治疗后6 h、治疗后第4、 7、 11、 15、 28天内眦静脉取血, 进行血常规检测, 分析荷瘤小鼠外周血象与荷瘤小鼠肿瘤结节缩小之间的相关性.结果: 7.5 mg/kg美法仑治疗后, 荷瘤小鼠肿瘤消退;而对照组荷瘤小鼠肿瘤继续生长.美法仑治疗后6 h外周血白细胞为(10.6±2.3)×109/L, 与治疗前(9.8±0.32)×109/L比较差异无统计学意义(P>0.05);治疗后第4天外周血白细胞降为(2.9±0.97)×109/L, 与治疗前比较差异具统计学意义(P<0.01), 随后尽管白细胞数有所回升, 但在治疗后第28天仍明显低于化疗前水平(P<0.01).Hb含量在美法仑治疗后6 h由化疗前的(132±7) g/L降为(110±14) g/L(P<0.05), 随后Hb含量持续降低, 治疗后第7天达最低点(96±5) g/L, 以后逐渐升高, 治疗后15 d恢复至化疗前水平.用药后6 h荷瘤小鼠血小板计数升至(1502±142)×109/L, 与用药前(914±322)×109/L比较差异具有统计学意义(P<0.01), 随后1周内一直维持在高水平, 治疗后第11天血小板恢复至化疗前水平.结论: 美法仑在使荷瘤小鼠的肿瘤结节缩小的同时可引起外周血白细胞数和血红蛋白浓度的降低, 但对血小板无抑制作用.美法仑化疗后1周内血小板计数的增加可能与美法仑的抗肿瘤作用有关.     

异基因嵌合体与移植耐受关系的研究Ⅱ成年小鼠联体共生诱导耐受的机制

将BALB/c(H 2 d)小鼠及C5 7BL/ 6 (H 2 b,B6 )小鼠的脾细胞分别经尾静脉注射给对方 ,2d后再分别腹腔注射环磷酰胺 (CY ) 15 0mg/kg ,CY注射后 1d对BALB/c及B6小鼠进行联体 (parabiosis) ,1周后分开并进行相互间的植皮。发现BALB/c小鼠对B6小鼠的皮肤耐受期明显延长 (MST =2 5 7d ) ,但是B6对BALB/c小鼠的皮肤耐受期无明显延长 (MST =11 9d )。利用流式细胞仪分析技术 (FACS )分别对上述处理的BALB/c及B6小鼠在联体分开后的第 1天和第 30天进行胸腺及脾脏嵌合程度的检查 ,发现皮肤耐受期与嵌合程度不呈正相关。对联体后耐受的BALB/c小鼠进行体内和体外细胞转移实验 ,均未显示耐受小鼠脾细胞中存在抑制细胞活性。在耐受BALB/c→B6小鼠的单向混合淋巴细胞反应 (MLR )体系中加入外源IL 2可以部分反转耐受BALB/c小鼠脾细胞的增殖反应 ,表明本实验诱导耐受的机制可能与克隆不应答 (clonalanergy )有关。     

Adoptive immunotherapy of murine pulmonary metastases with interleukin 2 and interferon-gamma

We examined the activities of activated lymphocytes, interferon-gamma (IFN-gamma), and interleukin 2 (IL-2) in adoptive immunotherapy of pulmonary metastases. Pulmonary metastases produced in Balb/c mice by a single tail-vein injection of 5 X 10(5) murine sarcoma (MCB8) tumor cells on day 0 were treated with combinations of Con A-activated lymphocytes (CAL) (3 X 10(7) cells on days 3 and 7), IL-2 (5 X 10(4) U three times a day on days 3 to 8), and IFN-gamma (5 X 10(4) U/mouse on days 1 to 8). Treated tumors contained increased numbers of infiltrating Thy-1.2+ lymphocytes and a predominance of L3T4+(CD4+) lymphocytes. The level of expression of class I and class II MHC antigens by tumor cells in the lung was increased after treatment. Mice that received CAL + IL-2 + IFN-gamma showed approximately 80% reduction in tumor burden as compared to controls (P = 0.001). Mice treated with IL-2 + CAL, or IL-2 + IFN-gamma, displayed approximately 50% reduction (both P less than 0.02 as compared to triple therapy), whereas IL-2, IFN-gamma, or CAL administered as single agents had little effect on pulmonary metastases. We conclude that adoptive immunotherapy with activated lymphocytes and IL-2 is enhanced by IFN-gamma.     

Beneficial effect of amrinone on murine cardiac allograft survival.

Amrinone is a non-glycoside positive inotropic agent with an inhibitory effect on a cyclic adenosine monophosphate (AMP) phosphodiesterase isoenzyme. In the present study, we examined the immunosuppressive action of amrinone, since several other cyclic AMP-elevating agents have been shown to suppress T lymphocyte activation. First, the in vivo effects of amrinone were investigated. Oral amrinone treatment, at 40 mg/kg per day, significantly prolonged median cardiac allograft survival compared with non-treated controls (22.0 days versus 10.5 days, P < 0.01) when DBA/2 mouse hearts (H-2d) were heterotopically transplanted into C57B1/6 mice (H-2b). Histopathological examination showed that there was less prominent cellular infiltration in the amrinone-treated than in the non-treated allografts. Plasma amrinone concentrations of mice after a single oral dose of 40 mg/kg were within the range of clinical relevance. To clarify the mechanism of action, in vitro studies were done. The generation of specific cytotoxic T lymphocytes after mixed lymphocyte culture was significantly suppressed by addition of amrinone to the culture medium at 5 micrograms/ml. The production of IL-2 and the interferon-gamma during mixed lymphocyte culture was also suppressed by amrinone at 5 micrograms/ml. However, the level of intracellular cyclic AMP in mouse splenic lymphocytes was not affected significantly by the same dose of amrinone. In conclusion, amrinone has immunosuppressive actions at the therapeutic doses, and it may be a beneficial agent for therapy against acute cardiac allograft rejection.     

Monoclonal Antibody Treatment (Anti-CD4 and Anti-Interleukin-2 Receptor) combined with Cyclosporin A has a Positive but not Simple Dose-Dependent Effect on Rat Renal Allograft Survival

The use of monoclonal antibodies (MoAbs) in experimental and clinical organ transplantation is of increasing interest since this treatment seems to offer an opportunity for specific immunomodulation. In a rat kidney allograft model, Cyclosporin A (CyA) treatment (12.5 mg/kg/d, day 0-14) was combined with murine anti-rat CD4 (MRC OX-38) and murine anti-rat IL-2R (MRC OX-39) MoAbs at doses of 100 or 300 micrograms/kg/d (day 0-7) and plasma concentrations of the murine MoAb were determined. In both groups receiving combined treatment with CyA and MoAb, graft survival was prolonged to an average of 65 days, compared to a graft survival of 9-10 days in non-treated recipients. Further, the data showed a beneficial effect of CyA + MoAb treatment versus CyA alone (graft survival 32 days). The threefold increased MoAb dose did not seem to improve graft survival or function. Treatment with OX-38 + OX-39 at a dose of 100 micrograms/kg/d each resulted in plasma levels of 280 ng/ml 14 days after transplantation. Corresponding values after the administration of 300 micrograms/kg/d were 1800 ng/ml in graft recipients as well as controls. These findings indicate that the effect of MoAbs in complex organ transplantation models is not simply dose dependent and that in vitro assays are of limited value in predicting the effect of a given MoAb when used in vivo. The determination of MoAb plasma levels, however, may be a useful tool in defining optimal MoAb administration and to monitor therapeutically effective plasma levels.     

Prophylactic administration of interleukin-2 protects mice from lethal challenge with gram-negative bacteria.

Prophylactic administration of recombinant human interleukin-2 (IL-2) in mice enhanced survival and produced complete recovery from an otherwise lethal acute bacterial infection. IL-2 was administered as a single intraperitoneal or intravenous bolus dose to CDI mice 18 h before challenge with a lethal dose of a clinical isolate of Escherichia coli type O2 (minimal 100% lethal dose, 6 X 10(7) CFU per mouse). At IL-2 dosages of 7 X 10(6) U/kg, 90% of treated CDI mice survived as compared to 0% for the excipient buffer control animals (P less than 0.001). This protective effect was also demonstrable in immune-deficient beige mice. The IL-2 effect was dose dependent; protection was consistently observed in mice pretreated with IL-2 at doses ranging from 1.8 X 10(6) to 7 X 10(6) U/kg. However, at 3.5 X 10(5) U/kg the protective effect was more variable. The route of administration of IL-2 was shown to play an important role; when IL-2 and challenge bacteria were given by the same route (either intravenously or intraperitoneally), protection was readily observable, but when IL-2 and challenge bacteria were given by different routes, little or no protective effect was observed. The protective effect was fully inducible as early as 1 h after IL-2 administration and was effective against various strains of gram-negative bacteria, indicating that the probable mode of action represents control of the establishment of infection by increased activity of the nonspecific host defense mechanisms. The IL-2 effect was abrogated by the administration of carrageenan, suggesting a possible role of macrophages. These data demonstrate that IL-2 may be a potentially useful adjunct for the prophylaxis of bacterial infections in both clinical and veterinary medicine.     

Glucocorticosteroid effects on dog and rat serum complement

Inhibiting properties of glucocorticosteroids in vivo on the complement system are not fully recognized. Dexamethasone and prednisolone (10(-7)-10(-3)mol/l.) have no direct effects on serum complement of the dog, rat, human and guinea pig. Yet after subcutaneous application of dexamethasone (0.4 mg/kg) on two consecutive days to healthy beagle dogs the total functional complement is reduced to about 60% of the normal level within the next three days. This effect could be shown to be dose-dependent in male beagle dogs. Partial recovery of the depressed complement level (CH50 U/ml) occurs after the 6th day without treatment. In parallel a decrease in serum C3 is observed. The qualitative serum protein pattern documented by cellulose acetate film electrophoresis (CAF) reflects the decrease of C3 by a reduced beta 1-beta 2 level with a concomitant increase of the alpha 2 serum proteins. In contrast, serum complement, C3 and the serum CAF pattern in rats are not much altered by prednisolone (2 X 15 mg/kg s.c.) or dexamethasone (2 X 2 mg/kg s.c.). Thus the rat appears relatively insensitive to humoral changes induced by steroid alone. Altered liver protein synthesis of complement and other acute phase proteins appear responsible for the profound steroid effects observed in the dog.     

The influence of dfp, atropine and toxogonine on tryptophan pyrolase activity in mouse liver.

It was found that fluorostigmine (DFP) in doses 0-4 mg/kg i.p. reduced significantly tryptophan pyrolase activity in mouse liver homogenates.se liver homogenates 120 and 180 min after the administration of the drug. On the other hand, fluorostigmine administered in doses 0-8 mg/kg i.p. increases the activity of the enzyme studied at 30 and 60 min after the injection. DFP (0.4 mg/kg i.p.) given in combination with atropine (10 mg/kg i.p.) causes a significant increase in enzyme activity determined 30, 60, 120 and 180 min after the administration of the drug. Toxogonine (in doses 5 mg/kg s.c.) given together with DFP (0.4 mg/kg i.p.) intensifies the activity of tryplophan pyrolase at 180 min after their administration. Simultaneous treatment with toxogonine (5 mg/kg s.c.), atropine (10 mg/kg i.p.) and DFP (0.4 MG/KG I.P.) reduced significantly the activity of the enzyme studied at all time of determination. Moreover, the experiment in vitro showed that DFP in concentrations of 4x10(-9) M; 8X10(-9) M; 1.6X10(-8) M and 3.2x10(-8) M increased tryptophan pyrolase activity in mouse liver homogenates.     

Immunological effects of refolded human soluble BAFF synthesized in Escherichia coli on murine B lymphocytes in vitro and in vivo

The B cell activating factor of the TNF family (BAFF, also known as BLyS, TALL-1, THANK, and zTNF4) is an important survival factor for B lymphocytes. Our previous study has demonstrated that the final purified material of human soluble BAFF (refolded hsBAFF) synthesized in Escherichia coli is biologically active in a validated induced human B lymphocyte proliferation bioassay. In this study, the administration of refolded hsBAFF to isolated mouse B lymphocytes and mice was carried out to study the immunological effects of hsBAFF on in vitro and in vivo B lymphocytes. The results showed that splenic B lymphocyte proliferation significantly increased after hsBAFF administration (in vitro 1, 2, 3, 5 microg/ml and in vivo 0.01, 0.5, 1.0 mg/kg body mass). An oppositely elevated immune response of B lymphocyte to LPS stimulation after hsBAFF administration (1, 2.5, 5 microg/ml) and a significantly elevated change after treatment with hsBAFF and costimulation with anti-IgM (2.5 microg/ml) was observed in vitro, respectively. A similar change existed also in hsBAFF-treated mice on the 8th postexperiment day, but the value with anti-IgM alone didn't increase compared to normal control in vitro. We found that the treatment of mice with hsBAFF resulted in a developmental maturation of T1 B lymphocytes to T2 and mature B lymphocytes by detecting distributions of splenic CD21(lo) with CD45R/B220(+) and CD21(hi) with CD45R/B220(+) subsets. These results suggest that the refolded hsBAFF synthesized in Escherichia coli may enhance immune responses in the body by regulating the proliferation, differentiation, and immune response of B lymphocytes.     

Additive effects of leflunomide and tacrolimus in prevention of islet xenograft rejection

Leflunomide is a low molecular weight immunosuppressive drug which inhibits the enzymes dehydroorotate dehydrogenase and protein tyrosine kinase, both of which are important components in the immune response. As the mechanisms of action of leflunomide and tacrolimus are different, we postulated an additive or synergistic effect of the two drugs and investigated the effects of leflunomide alone, or in combination with a suboptimal dose of tacrolimus, on xenogeneic islet transplantation in a rat-to-mouse model. A total of 1200-1500 rat islets were transplanted under the left kidney capsule of streptozotocin-induced diabetic BALB/c mice. The median survival time (MST) of the untreated group was 6 days. Leflunomide at 5, 10 and 20 mg/kg/d administrated for 10 days significantly prolonged MST to 10, 16 and 20 days. A dose of tacrolimus (2 mg/kg/d) was associated with a graft survival of 9 (range 6-12) days; most grafts rejected during ongoing therapy. When tacrolimus (2 mg/kg/d) was combined with leflunomide (10 mg/kg/d), the survival time of the islet xenografts was increased further to 22 days, significantly longer than with leflunomide or tacrolimus alone. In summary, our findings demonstrate that leflunomide prolonged xenogeneic islet graft survival, and that its immunosuppressive effect was improved when combined with tacrolimus.     

Neuroprotection and functional recovery conferred by administration of kappa- and delta 1-opioid agonists in a rat model of global ischemia

Studies that have evaluated the beneficial effect of pre-ischemic treatment of kappa-opioid receptor agonists have used short-term reperfusion intervals. We examined the long-term impact of the pre-ischemic peripheral injection of U50,488H (trans-3,4-dichloro-N-methyl-N-[2-(1-pyrrolidinyl)cyclohexyl]-benzeneacetamide), a selective kappa-opioid receptor agonist, on neuronal damage and behavioral deficits following global ischemia in rats. Four groups of ischemic rats were pretreated with various doses of U50,488H (i.p. 0, 5, 15, 30 mg/kg) 15 min prior to vessel occlusion. Two groups of sham-operated animals that received either saline or U50,488H (30 mg/kg) acted as controls. The injection of 30 mg/kg U50,488H led to a 65% increase in CA1 neuron survival 35 days post-ischemia. CA1 neuronal protection translated into significant improvement of ischemia-induced spatial memory deficits assessed in the 8-arm radial maze. However, there was no difference in activity in the open field. We also found that the pre-ischemic intracerebroventricular injection of 5 mug of the delta1-opioid receptor agonist DPDPE ([d-Pen(2,5)]-enkephalin) produced a 59% increase in CA1 neuron survival 7 days post-ischemia. Similar to U50,488H, DPDPE had no significant impact on locomotor activity. These findings support a role for kappa- and delta-opioid receptors in attenuation of ischemia-induced hippocampal damage and cognitive impairments.     

Large scale production of human lymphokine activated killer cells for use in adoptive immunotherapy

Immunotherapy utilizing the adoptive transfer of lymphokine activated killer (LAK) cells in conjunction with recombinant interleukin 2 (RIL-2) is capable of reducing established metastatic cancer in a variety of animal tumor models. A major difficulty in the application of these efforts to the treatment of human cancer has been the activation in vitro of up to 2 X 10(11) human peripheral blood lymphocytes obtained by repeated leukaphereses. We have thus developed optimal and simplified techniques for the generation of human LAK cells for use in clinical trials. We have found that 1.5 X 10(9) lymphocytes separated on Ficoll-Hypaque gradients and incubated in 1000 ml of culture medium in a 2.3 liter roller bottle with 1000-1500 U of RIL-2 per ml, generated LAK cells capable of killing fresh human tumor cells in a 4 h chromium release assay. The culture medium used was RPMI 1640 with 2 mM glutamine, 2% heat-inactivated human AB serum, 50 micrograms/ml streptomycin and gentamicin and 50 U/ml penicillin. This technique allows activation of sufficient numbers of cells in a research laboratory setting to conduct human clinical trials. The administration of LAK cells generated in this fashion can mediate the regression of human tumors when administered in conjunction with IL-2.