Alterations of both responder T cells and stimulator non-T cells are responsible for abnormal mixed lymphocyte reaction in aged humans

Summary The autologous and allogeneic mixed lymphocyte reactions of 15 young and 15 aged human adults were compared. Both autologous and allogeneic mixed lymphocyte reactions were significantly reduced in the aged group. T cells from aged adults displayed a reduced proliferative response to non-T cells of either aged or young adults. T cells from young adults also showed a reduced proliferative response to non-T cells from aged adults. Sera from aged adults, showing depression of autologous and allogeneic mixed lymphocyte reaction, did not exert any inhibitory effect on the autologous and allogeneic mixed reaction of lymphocytes from young donors. These data suggest that depression of mixed lymphocyte reaction in aged humans probably reflects intrinsic abnormalities of both responder T cells and stimulatory non-T cells. This work was supported by a grant from theConsiglio Nazionale delle Ricerche (CNR), Roma, Italy ‘Progetto Finalizzato Medicina Preventiva, Sottoprogetto Meccanissmi di Invecchiamento’.     

牙髓干细胞MHC分子表达与体外混合淋巴细胞的增殖

背景：若牙髓干细胞诱导分化后仍然具有与未分化时相似的免疫调节能力,则有可能为组织工程提供同种异体种子细胞来源。目的：观察牙髓干细胞表面免疫分子的表达以及体外调节淋巴细胞反应的功能。方法：从C57BL/6小鼠牙髓组织中分离获取牙髓干细胞,体外培养至第2代,流式细胞仪检测免疫分子MHC-Ⅰ、MHC-Ⅱ的表达。以1×105/孔牙髓干细胞刺激异体淋巴细胞,观察细胞增殖情况。以1×105/孔数量的牙髓干细胞或经γ-干扰素作用后的牙髓干细胞加入混合双向淋巴细胞反应体系中,观察淋巴细胞增殖情况。结果与结论：牙髓干细胞表达MHC-Ⅰ类分子,但未检测到MHC-Ⅱ类分子阳性表达。γ-干扰素刺激48 h后,MHC-Ⅰ表达未见明显增高,MHC-Ⅱ类分子表达明显增高。异体或经γ-干扰素作用的牙髓干细胞均未能刺激淋巴细胞体外增殖。说明牙髓干细胞可在体外调节淋巴细胞增殖反应,有可能成为组织工程或细胞治疗中同种异体细胞来源。     

Effects of bile salts and aliphatic ionic surfactants on human lymphocyte proliferation

BACKGROUND: The molecular mechanisms involved in the immunosuppressive properties of bile salts are partly unknown. METHODS: The aim of the study was to compare the effects of bile salts to those of various compounds with a steroid structure, or straight-chain hydrocarbons of different lengths and polar groups in the human mixed lymphocyte reaction. RESULTS: We showed a significant correlation between the effects of bile salts and a low critical micellar concentration, a high surface activity index, and the absence of conjugation. In addition to mixed lymphocyte reaction (MLR) inhibition, chenodeoxycholate (CDC) inhibit ConA-induced IL2 production without any effect on IL2 R expression. Fusidate, a negatively charged steroid, with physical properties comparable to those of deoxycholate, had similar effects. Cetyltrimethylammonium bromide (CTAB), which exhibited a very low critical micellar concentration, inhibited mixed lymphocyte reaction in an extent comparable to cyclosporin A. In contrast, aliphatic compounds with critical micellar concentrations in the same range as bile salts but with a lower molecular area had no effect. CONCLUSIONS: Amphiphilic negatively charged molecules inhibit T-cell proliferation to an extent that is dependent upon their hydrophobicity. These results may be explained, at least in part, by a modification in the cell membrane lipid bilayer structure.     

骨髓间充质干细胞对致敏小鼠淋巴细胞增殖的影响及其作用方式

本研究探讨骨髓间充质干细胞(mesenchymal stem cells,MSC)在体外对致微小鼠淋巴细胞增殖的影响及其作用方式,以便进一步了解MSC对致敏小鼠影响的可能机制.建立致敏模型后,将应用贴壁培养法体外培养的正常小鼠骨髓MSC或其培养上清液作为免疫细胞或免疫因子,致敏小鼠的淋巴细胞作为效应细胞,用植物血凝素( phytohemagglutinin,PHA)刺激淋巴细胞增殖,在体外应用MTT法检测两者的混合淋巴细胞增殖反应.结果表明,正常小鼠骨髓MSC在体外能很好地抑制致敏小鼠脾淋巴细胞增殖,同时在MSC培养上清液也能观察到类似现象,而且随着两者细胞比例或浓度比的增大,抑制作用有所加大,当两者比例为1∶1时抑制作用最大(有明显的统计学意义).结论:MSC能在体外明显抑制致敏小鼠脾淋巴细胞增殖,该作用可以通过细胞与细胞(MSC和淋巴细胞)直接接触抑制,也可通过细胞与细胞的间接作用(如MSC的培养上清液与淋巴细胞)方式发挥作用.     

Enzyme induction and inhibition by new antiepileptic drugs: a review of human studies

The aim of this paper is to review a number of new antiepileptic agents (i.e. felbamate, gabapentin, lamotrigine, levetiracetam, oxcarbazepine, tiagabine, topiramate, vigabatrin and zonisamide) for their inducing and/or inhibitory properties in humans, mainly considering the interactions where they are involved as the cause rather than the object of such interactions. Two aspects have been particularly taken into account: the changes or absence of changes in plasma/serum concentrations of concomitant drugs and the direct or indirect evidence of induction, inhibition or lack of effect on the six major human hepatic CYP isozymes (CYP1A2, CYP2C9, CYP2C19, CYP2D6, CYP2E1 and CYP3A4), as well as on other CYP isozymes or enzyme systems. Felbamate clearly affects the pharmacokinetics of a number of drugs, generally increasing but also decreasing their concentrations. It induces enzymes such as CYP3A4 and inhibits enzymes such as CYP2C19 and those of the beta-oxidation pathway. Topiramate is not devoid of potential interaction properties: it decreases the plasma concentrations of ethinylestradiol, induces CYP3A4 and inhibits CYP2C19. For oxcarbazepine, no inhibitory, only inductive effects have been observed thus far. Felbamate. topiramate and oxcarbazepine may induce the metabolism of steroidal oral contraceptives. In this respect, tiagabine has been studied at a rather low dose. Pharmacodynamic or pharmacokinetic interaction seems to exist between lamotrigine and carbamazepine. Lamotrigine appears to be a weak inducer of UGTs, whereas induction of CYP3A4 seems improbable as the compound does not change the concentrations of oral contraceptives or the urinary excretion of 6beta-hydroxycortisol. Zonisamide has very peculiar pharmacokinetics and an extensive metabolism. Additional information on its enzyme inducing or inhibiting properties would be necessary, as data so far collected on its effect on the pharmacokinetics of other drugs are conflicting. Gabapentin, vigabatrin and in particular levetiracetam appear to be devoid of significant enzyme inducing or inhibiting properties.     

Phenytoin in the Treatment of Inducible Ventricular Tachycardia: Results of Electrophysiologic Testing and Long-Term FoUow-Up

Phenytoin treatment of inducible ventricular tachyarrhythmias was assessed by serial electrophysiologic studies (EPS) in 64 patients with spontaneous ventricular tachycardia, cardiac arrest, or symptoms compatible with a ventricular tachyarrhythmia. Coronary artery disease was the primary cardiac disease in 75% of the patients. All subjects had either inducible ventricular tachycardia (greater than or equal to 10 repetitive beats) or ventricular fibrillation at electrophysiologic study. Phenytoin was administered intravenously in 38 studies and orally in 31 studies. The mean serum phenytoin level was 19.5 +/- 4.7 mcg/ml. Only seven patients (11%) had a negative electrophysiologic study (less than or equal to 10 repetitive beats) after the administration of phenytoin and were classified as phenytoin responders (group I). The remaining 54 patients (89%) were classified as nonresponders (group II). For the nonresponders, phenytoin increased the cycle length of identical monomorphic ventricular tachycardias from a mean of 31 ms to a mean of 327 ms (p less than 0.001). For the four patients tested receiving both intravenous and oral phenytoin, the intravenous response always predicted the oral response. For the seven patients in whom electrophysiologic study indicated phenytoin efficacy, two are alive and arrhythmia-event free, two had sudden death when the regimen was changed (one case, quinidine added; one case, subtherapeutic serum level), and three died from nonarrhythmic causes. For the 10 patients treated empirically with phenytoin, either alone (seven patients) or in combination with another antiarrhythmic agent (three patients), four died secondary to an arrhythmic event.(ABSTRACT TRUNCATED AT 250 WORDS)     

Serum LDL cholesterol,the LDL/HDL cholesterol ratio and liver microsomal enzyme induction evaluated by antipyrine kinetics

The association of serum LDL and HDL cholesterol with hepatic microsomal enzyme induction, assessed by plasma antipyrine kinetics was investigated in 30 epileptics. Patients on enzyme-inducing anticonvulsants had reduced LDL/HDL cholesterol ratios and elevated HDL cholesterol concentrations and HDL/total cholesterol ratios, indicating a cholesterol transfer from LDL to HDL. Strong hepatic microsomal enzyme induction was associated with reduced LDL cholesterol. The LDL/HDL cholesterol ratio was negatively proportional and the HDL/total cholesterol ratio positively proportional to the antipyrine clearance rate. Epileptics, particularly those with a high antipyrine clearance, had a cholesterol distribution pattern characteristic of a low probability of developing coronary atherosclerosis. The results support the view that hepatic microsomal enzyme induction favourably alters the cholesterol distribution in the body.     

Folate Deficiency in Malnutrition, Malabsorption, and During Phenytoin Treatment Diagnosed by Determination of Serine Synthesis in Lymphocytes

Abstract A new method for the detection of folate deficiency by measuring the rate of incorporation of ¹⁴C-formate into serine in isolated lymphocytes has been applied to a group of 24 control subjects and 23 patients. 5 of the patients suffered from malnutrition, 14 had malabsorption and 4 were under treatment with phenytoin.
In 17 of these patients, functional folate deficiency was diagnosed by a decreased rate of serine synthesis in the lymphocytes. 11 cases of folate deficiency were found by measuring the folate concentration of erythrocytes by the L. casei method. The lymphocyte method failed in only one case out of 18.
In the 24 control subjects the average incorporation of ¹⁴C-formate into serine per 10⁹ lymphocytes per 4 h was 9.2 ± 0.4% (range 6.3–14.3 %) of added activity. For 16 patients with functional folate deficiency, the corresponding value was 4.1 ± 0.3% (range 1.0–5.9%). The folate activities of lymphocytes from 12 patients before and after 4 weeks of oral treatment with 15 mg folic acid daily were 3.4±0.3 and 7.5±1.0% respectively. The lymphocytes responded within 4 weeks to deprivation of or treatment with folic acid.
The ¹⁴C-formate incorporation into methionine, RNA sad protein showed the same pattern as the incorporation into serine.     

Autologous mixed lymphocyte reaction in the peripheral blood and pleural effusions of cancer patients.

T cells proliferate in response to autologous non-T cells in the autologous mixed lymphocyte reaction (AMLR). AMLR was impaired in the peripheral blood of patients with advanced lung cancer (4,159 +/- 3,878 delta cpm vs. 11,221 +/- 4,156 delta cpm for normal donors) but normal or even higher in their malignant pleural effusions (13,257 +/- 7,075 delta cpm vs. 10, 870 +/- 5,013 delta cpm for nonmalignant control effusions). Blood T cells also failed to respond to autologous effusion non-T cells, while effusion T cells strongly responded to autologous erythrocytes blood non-T cells. The presence of blood T cells did not inhibit effusion AMLR of the same patients. A subset of T cells that form rosettes with autologous erythrocytes if found to proliferate in AMLR. The number of autorosette-forming cells was lower in blood T cells of cancer patients than in blood T cells of normal donors and in effusion T cells of the patients. After enrichment of autorosette-forming cells, there was no difference in AMLR of normal blood and cancer blood and effusions. These results indicate that the loss of AMLR in the blood of cancer patients is due to a reduction of number of autoreactive T cells and not to a defect of autologous stimulator non-T cells.     

Pharmacokinetic assessment of immunosuppressive activity of antibiotics in human plasma by a modification of the mixed lymphocyte reaction

Antibiotics may impair the development and expression of specific or nonspecific immune responses. Prophylactic administration of antibacterial antibiotics is widely used in ICUs. We studied the immunosuppressive activities of cefotaxime, chloramphenicol, gentamicin, metronidazole, and rifamycin as a function of time after the administration of these drugs to ICU patients, finding that the last 4 drugs had an immunosuppressive activity detectable up to 8 h by a mixed lymphocyte reaction. When these antimicrobial agents were added to normal pooled plasma in concentrations similar to those obtained in vivo, a similar degree of inhibition was observed.     

Influence of enzyme induction and inhibition on the oxidation of nifedipine, sparteine, mephenytoin and antipyrine in humans as assessed by a "cocktail" study design

Nifedipine (NF), sparteine (SP), mephenytoin (MP) and antipyrine (AP) were administered simultaneously ("cocktail" design) to 15 healthy subjects, including 4 poor metabolizers (PM) of SP and 4 PMs of MP, on three different occasions: without pretreatment, after pentobarbital (PB) pretreatment and together with cimetidine (cim). Concentrations of AP, NF, its pyridine metabolite 2,6-dimethyl-4-(2-nitrophenyl)-pyridine-3,5-dicarboxylate-methylester (M-O), SP, dehydrosparteine (DHS) were determined in plasma; 2,6-dimethyl-4-(2-nitrophenyl)-pyridine-3,5-dicarboxylate-monomethyle ster (which is ester hydrolyzed M-O), SP, DHS, 4-hydroxymephenytoin, AP and metabolites 3-hydroxymethylantipyrine, norantipyrine and 4-hydroxyantipyrine were measured in urine. Clearance of NF had increased 270% after PB and decreased 32% with cim. Area under the plasma-concentration time curve of M-O and urinary excretion of 2,6-dimethyl-4-(2-nitrophenyl)-pyridine-3,5-dicarboxylate-monoethyles ter had also decreased after PB. Neither extensive metabolizers nor PMs of SP and MP were sensitive to PB treatment, but sparteine clearance was reduced 55% by cim in extensive metabolizers and 59% in PMs. Ratio SP/DHS in urine was hardly influenced by cim. AP oxidation was significantly induced and inhibited by PB and cim, respectively. The cocktail study design seems to be suitable to assess induction and inhibition of the metabolism of the applied model substrates, which are metabolized by at least partly independent isozymes of the cytochrome P-450 system, simultaneously.     

MG132诱导HL-60细胞表达共刺激分子CD86及其对混合淋巴细胞反应的影响

本研究探讨蛋白酶体抑制剂MG132诱导HL-60细胞表达共刺激分子CD80、CD86及其对混合淋巴细胞反应的作用.流式细胞仪检测MG132诱导HL-60细胞表达共刺激分子CD80、CD86及细胞活力;逆转录聚合酶链反应（RT-PCR）分析CD80和CD86 mRNA表达情况;MG132诱导HL-60细胞表达共刺激分子CD86后,用75 GyCo-60照射HL-60细胞,杀死HL-60细胞,保留抗原性作为刺激细胞,用健康人外周血单个核细胞作为反应细胞,用不同浓度HL-60细胞刺激健康人单个核细胞,HL-60细胞对健康人单个核细胞的增殖作用.结果表明：MG132上调HL-60细胞表达CD86,MG132诱导HL-60细胞的凋亡率呈浓度依耐性和时间依耐性.结论：高浓度的MG132对HL-60细胞有直接杀灭作用,低浓度MG132诱导HL-60细胞表达共刺激分子CD86,对健康人单个核细胞有增殖作用.MG132诱导HL-60细胞表达共刺激分子CD86,能促进健康人单个核细胞的增殖.     

Population pharmacokinetics of phenobarbital by mixed effect modelling using routine clinical pharmacokinetic data in Japanese neonates and infants: an update

What is known and objective: Optimal use of phenobarbital in the neonatal population requires information regarding the drug’s pharmacokinetics and the influence of various factors, such as different routes of administration, on the drug’s disposition. However, because of sampling restrictions, it is often difficult to perform traditional pharmacokinetic studies in neonates and infants. This study was conducted to establish the role of patient characteristics in estimating doses of phenobarbital for neonates and infants using routine therapeutic drug monitoring data. Methods: The population pharmacokinetics of phenobarbital was evaluated using 109 serum concentration measurements obtained from routine phenobarbital monitoring of 70 neonates and infants. The data were analysed using the non‐linear mixed effects model. A one‐compartment pharmacokinetic model with first‐order elimination was used. Covariates screened were current total bodyweight (TBW), gestational age, postnatal age (PNA), post‐conceptional age, gender and neonates‐infants clearance factor (serum concentration of phenobarbital; Conc). Results and discussion: The final pharmacokinetic parameters were CL/F (mL/h) = (5·95·TBW (kg) +1·41·PNA (weeks)) Conc (serum phenobarbital concentration >50 μg/mL)^?0·221,Vd/F (L) =1·01·TBW (kg), and F = 0·483 for oral administration and F = 1 was assumed for suppository. Conc^?0·221 is 1 for phenobarbital concentration <50 μg/mL. The important variables for predicting phenobarbital clearance in this study were TBW, PNA and Conc. Phenobarbital clearance increases proportionately with increasing TBW, and an older newborn was expected to have a higher rate of clearance than a younger newborn of equal bodyweight. Moreover, the clearance of phenobarbital decreased nonlinearly with increasing serum concentration of phenobarbital >50 μg/mL (Conc^?0·221). What is new and conclusion: We developed a new model for neonate and infant dosing of phenobarbital with good predictive performance. Clinical application of our model should permit more accurate selection of initial and maintenance doses to achieve target phenobarbital concentrations in Japanese neonates and infants, thereby enabling the clinician to achieve the desired therapeutic effect. A similar approach can be used to validate our model for use in other neonate and infant populations.     

Age-dependent changes in the rate of myofibrillar protein degradation in humans as assessed by 3-methylhistidine and creatinine excretion.

1. Urinary excretion of 3-methylhistidine and creatinine have been measured in normal male and female humans ranging in age from pre-term neonates to 68 years to assess changes in the rate of muscle protein degradation and in muscle mass. 2. The 3-methylhistidine excretion by six adult men was measured before and after subjects were transferred to meat-free diets. It was established that a meat-free diet should be eaten for a minimum of 3 days before urine collection to eliminate exogenous sources of 3-methylhistidine. 3. The 3-methylhistidine/creatinine excretion ratio declined about twofold between normal full-term birth and maturity. The ratio in pre-term neonates was higher than for full-term neonates. 4. The variability of 3-methylhistidine/creatinine ratios between individual untime urine samples within a subject is similar to the variability between different subjects with total daily collections. 5. The 3-methylhistidine content of human muscle averaged 3.63 +/- 0.06 micromol/g for subjects aged between 4 and 65 years with protein accounting for 20.4 +/- 0.8% of muscle weight. These values are used to relate 3-methylhistidine excretion to muscle protein degradation. 6. It is concluded that control groups must be matched by age and sex to the group being examined. Where creatinine excretion is not perturbed it can be used as a reference base for comparisons of 3-methylhistidine excretion to indicate the average fractional degradation rates of muscle protein.     

Induction of suppressor activity in the autologous mixed lymphocyte reaction and in cultures with concanavalin A.

T lymphocytes that are activated in the autologous mixed lymphocyte reaction (MLR) have suppressor activity. Concanavalin A (Con A) augments the suppressor activity generated in cultures containing both T and non-T lymphocytes and can induce suppressor activity in T-lymphocyte preparations that contain too few (10%) non-T cells to generate a significant autologous MLR. However, when such T-lymphocyte preparations are further depleted of adherent cells and contain less than 2% non-T cells, Con A fails to induce suppressor activity. These findings support the concept that an autologous MLR may play an important role in generation of suppressor cells by Con A.     

Efficient identification of novel HLA-A(*)0201-presented cytotoxic T lymphocyte epitopes in the widely expressed tumor antigen PRAME by proteasome-mediated digestion analysis

We report the efficient identification of four human histocompatibility leukocyte antigen (HLA)-A(*)0201-presented cytotoxic T lymphocyte (CTL) epitopes in the tumor-associated antigen PRAME using an improved "reverse immunology" strategy. Next to motif-based HLA-A(*)0201 binding prediction and actual binding and stability assays, analysis of in vitro proteasome-mediated digestions of polypeptides encompassing candidate epitopes was incorporated in the epitope prediction procedure. Proteasome cleavage pattern analysis, in particular determination of correct COOH-terminal cleavage of the putative epitope, allows a far more accurate and selective prediction of CTL epitopes. Only 4 of 19 high affinity HLA-A(*)0201 binding peptides (21%) were found to be efficiently generated by the proteasome in vitro. This approach avoids laborious CTL response inductions against high affinity binding peptides that are not processed and limits the number of peptides to be assayed for binding. CTL clones induced against the four identified epitopes (VLDGLDVLL, PRA(100-108); SLYSFPEPEA, PRA(142-151); ALYVDSLFFL, PRA(300-309); and SLLQHLIGL, PRA(425-433)) lysed melanoma, renal cell carcinoma, lung carcinoma, and mammary carcinoma cell lines expressing PRAME and HLA-A(*)0201. This indicates that these epitopes are expressed on cancer cells of diverse histologic origin, making them attractive targets for immunotherapy of cancer.     

慢性乙型肝炎患者外周血T淋巴细胞亚群变化与病毒复制的关系

目的探讨慢性乙型肝炎患者外周血T淋巴细胞亚群变化与乙型肝炎病毒（HBV）复制的关系。方法用流式细胞术对81例慢性乙型肝炎患者和30名健康对照者进行外周血T淋巴细胞亚群检测,用荧光定量聚合酶链反应（PCR）测定血清中的HBV DNA含量。结果慢性乙型肝炎患者外周血CD3＋、CD4＋T细胞百分率及CD4＋/CD8＋比值较健康对照者显著降低,而CD8＋T细胞百分率显著升高。与健康对照组相比,HBV DNA阴性患者只有CD4＋/CD8＋比值变化显著;HBV DNA阳性患者CD3＋、CD4＋、CD8＋T细胞百分率及CD4＋/CD8＋比值有显著改变,但高拷贝组和低拷贝组相比,差异无统计学意义。结论慢性乙型肝炎患者感染HBV后免疫功能下降与病毒复制有关,HBV复制可进一步加重免疫功能紊乱。     

shRNA介导的RNA干扰对小鼠T淋巴细胞CD28基因的沉默效应

目的 探讨短发夹状RNA(shRNA)对C57BL/6J小鼠T淋巴细胞CD28共刺激分子基因沉默效应,评价shRNA对目的 基因干扰效应的时效性和稳定性,筛选出高效的干扰序列用于后期的动物实验.方法 首先构建3个载有CD28特异性shRNA(shRNA1～3)的表达质粒和1个非特异性shRNA表达质粒,将其分别转染小鼠脾淋巴细胞,以非特异性的shRNA表达质粒组和未转染组分别作为阴性对照和空白对照,采用实时荧光定量PCR和Western blot方法分别从基因和蛋白质水平评价转染l～20 d内CD28 shRNA对CD28基因的干扰效应,并筛选出干扰效率最高的序列.结果 ①成功构建了CD28 shRNA表达载体;②3种CD28 shRNA均可在mRNA和蛋白质水平有效沉默目的 基因,与实验对照组比较差异有统计学意义(P＜0.01):CD28 mRNA拷贝数持续降低,3种CD28 shRNA转染C57BL/6J小鼠脾细胞20 d,小鼠脾细胞CD28 mRNA拷贝绝对数分别下降了99.62%、99.89%和99.80%;CD28蛋白表达水平分别降低了(84.90±0.65)%、(96.49±0.03)%和(91.76±0.32)%,以CD28 shRNA 2组的抑制效率最高(P＜0.01).结论 ①特异性的CD28 shRNA可长期、稳定地介导CD28基因沉默;②针对CD28基因不同位点的不同shRNA也有干扰效率的差异.     

Suppression of the mixed lymphocyte reaction in man by a soluble T-cell factor. Specificity of the factor for both responder and stimulator

J.H., an HLA-Dw2 homozygous multiparous woman, fails to respond to her husband, W.H. (HLA Dw1,-) in the unidirectional mixed lymphocyte reaction. T cells from J.H. were previously shown to suppress the responses of Dw2-positive cells but not Dw2-negative cells to W.H. We now report that a soluble factor released into the supernate of the mixed lymphocyte reaction by J.H. T cells, mediates this suppression. Like the cell from which it is derived, the factor is highly specific for HLA Dw2 in the responder cell and partially specific for the stimulatory alloantigen.