Does proliferation capacity of lymphocytes depend on human blood types?

In vitro human lymphocyte culture methodology is well established yet certain confounding factors such as age, medical history as well as individual’s blood type may potentially modulate in vitro proliferation response. These factors have to be carefully evaluated to release reliable test report in routine cytogenetic evaluation for various genetic conditions, radiation biodosimetry, etc. With this objective, the current study was focused on analyzing the proliferation response of lymphocytes drawn from 90 individuals (21-29 years) with different blood types. The proliferation response was assessed in the cultured lymphocytes by cell cycle, mitotic index (MI), and nuclear division index (NDI) after stimulation with phytohaemagglutinin (PHA). To investigate the toxic effect on proliferation, MI was calculated in representative samples of each blood type were X-irradiated. The results showed that there was no significant difference among the cell cycle phases of lymphocytes in different blood types (P > 0.05). Similarly, both MI and NDI of lymphocytes derived from different blood types also did not show significant difference ( P > 0.05). The extensive interindividual variation within and among the blood types is likely responsible for the lack of significant difference in lymphocyte proliferation. Although spontaneous proliferation efficiency of lymphocytes of different blood types after PHA stimulation was grossly similar, the MI observed after radiation exposure showed a significant difference ( P < 0.05) indicating a differential proliferation response among the blood types. Our results suggest that the blood types did not have any impact on PHA-induced proliferation; however, a specific differential lymphocyte proliferation observed after radiation exposure needs to be considered.     

STAT5 signaling in expression of the α-subunit of interleukin-2 receptor in human blood lymphocytes

A comparative study of STAT3 and STAT5 activity (assessed by tyrosine phosphorylation level) and the expression of an α-subunit of the interleukin-2 receptor (examined by cytophotometric evaluation of CD25 cell number) during phytohemaglutinin (PHA)-induced proliferation of human blood lymphocytes (HBLs) has been carried out. It was found that the level of STAT3 phosphorylation was high both in resting and competent HBLs and remained unchanged in the presence of PHA or interleukin-2 (IL-2). In contrast to STAT3, phosphorylation of STAT5 was not seen either in resting or competent HBL. In the presence of PHA, STAT5 phosphorylation was observed no earlier than in 2–5 h; maximal phosphorylation was detected after 24 h. In competent HBLs, exogenous IL-2 induced high phosphorylation of STAT5 in 30 min that was retained for the next 24–48 h. Alterations in the level of tyrosine phosphorylation of STAT5 correlated with CD25 expression. WHI-P131, a JAK3 kinase inhibitor, prevents STAT5 activation, CD25 surface expression, and lymphocyte proliferation. It is concluded that JAK3/STAT5 signaling via an IL-2 receptor is necessary to support the long-term expression of a high-affinity αβγ_c-receptor of IL-2 and HBL optimal proliferation.     

E rosette formation at 37°:A property of mitogen-stimulated human peripheral blood lymphocytes

Peripheral blood lymphocytes from healthy humans formed stable E rosettes with sheep erythrocytes (SRBC) at 37°C after culture with phytohemagglutinin or the divalent cation ionophore A23187. Cells manifesting this phenomenon exhibited “blast” morphology, appeared by 16 hr of culture, increased dramatically in percentage and absolute number by 62 hr, and persisted in large numbers for the duration of culture (182 hr). Unstimulated lymphocytes formed rosettes at 4°C but not at 37°C. Increased “stickiness” due to surface-bound lectin mitogen was not the cause of rosette formation at 37°C.Formation of E rosettes at 37°C has previously been considered a property of lymphocytes less differentiated than the circulating T cell (e.g., thymocytes, leukemic lymphoblasts). The present findings indicate that this property can be “reexpressed” during blastogenesis in culture.This observation also demonstrates technical problems associated with the use of SRBC to quantitate lymphocytes with complement receptors (B cells) by the EAC rosette assay in culture. False positives resulted from 37°C E rosette formation, but this was overcome by replacing the SRBC with guinea pig erythrocytes in the EAC assay.     

Enhancement of the antibody-dependent cellular cytotoxicity of human peripheral blood lymphocytes with interleukin-2 and interferon α

Antibody-dependent cellular cytotoxicity (ADCC) is regarded as an important mechanism by which monoclonal antibodies (mAb) can exert an antitumour effect in vivo. It may be possible, therefore, to enhance the therapeutic efficacy of mAb by cytokines that are able to enhance the ADCC of human CD3^–, CD56⁺, CD16⁺ natural killer (NK) cells. We investigated in vitro the effects of recombinant interferon (rIFN) and recombinant interleukin 2 (rIL-2), alone or in combination, on the ADCC of human peripheral blood NK cells. Both cytokines enhanced the ADCC of the human effector cells. rIFN induced a maximally increased ADCC after an exposure of human effector cells to 20 IU/ml for 15–30 min, while rIL-2 induced optimal ADCC after incubation of the cells for 2 days in 20–50 U/ml. We now show that activation of the NK cells with a combination of rIL-2and rIFN induced significantly higher levels of ADCC than either cytokine alone. The highest ADCC was induced if the cells were first exposed to rIL-2 before rIFN was added to the culture. Culture of NK cells in medium or rIL-2 decreased the expression of FcRIII (CD16), indicating that intensity of CD16 expression and level of ADCC are not directly correlated, although blocking experiments with a mAb directed against CD16 showed that this FcR was essential for ADCC of the human effector cells.Supported by a grant from the Dutch Cancer Society (grant NKI-84-14)     

The human lymphocyte micronucleus assay: Response of cord blood lymphocytes to γ-irradiation and bleomycin

The induction of micronuclei in human cord blood lymphocytes by treatment with γ-irradiation and bleomycin has been measured. Culture durations which gave peak MN frequencies were determined. The lowest tested doses, 0.1 Gy irradiation and 1.25 μg/ml bleomycin, produced significant increases in the frequency of micronuclei. The spontaneous frequency of micronucleated lymphocytes in 28 cord blood samples ranged between 0.5 and 9.5 per thousand lymphocytes, with a modal value of 2.5. The method is evaluated for its potential usefulness in monitoring populations for chromosome breakage.     

Establishment of dose-response relationships between doses of Cs-137 γ-rays and frequencies of micronuclei in human peripheral blood lymphocytes

It has been suggested that the yield of micronuclei in human peripheral blood lymphocytes could be used as a biological dosimeter in cases of radiation exposure. In the present study micronuclei were induced in lymphocytes by exposing human blood samples in vitro to various doses of Cs-137 γ-rays. The blood samples were then cultivated using the cytokinesis block method. Coded programs were employed to establish the relationships between the frequencies of micronuclei and various doses of γ-rays. The best fit was obtained by the linear-quadratic model, Y = c + aD + bd², where Y is the yield of micronuclei, D is the dose in Gy and c, a, b, are constants. It seems there is a correlation between the yields of MN in mononuclear cells and the corresponding doses of radiation. Therefore an attempt was made to include these MN in the calculation of the dose-response relationship.     

Edaravone protects human peripheral blood lymphocytes from γ-irradiation-induced apoptosis and DNA damage

Radiation-induced cellular injury is attributed primarily to the harmful effects of free radicals, which play a key role in irradiation-induced apoptosis. In this study, we investigated the radioprotective efficacy of edaravone, a licensed clinical drug and a powerful free radical scavenger that has been tested against γ-irradiation-induced cellular damage in cultured human peripheral blood lymphocytes in studies of various diseases. Edaravone was pre-incubated with lymphocytes for 2 h prior to γ-irradiation. It was found that pretreatment with edaravone increased cell viability and inhibited generation of γ-radiation-induced reactive oxygen species (ROS) in lymphocytes exposed to 3 Gy γ-radiation. In addition, γ-radiation decreased antioxidant enzymatic activity, such as superoxide dismutase and glutathione peroxidase, as well as the level of reduced glutathione. Conversely, treatment with 100 μM edaravone prior to irradiation improved antioxidant enzyme activity and increased reduced glutathione levels in irradiated lymphocytes. Importantly, we also report that edaravone reduced γ-irradiation-induced apoptosis through downregulation of Bax, upregulation of Bcl-2, and consequent reduction of the Bax:Bcl-2 ratio. The current study shows edaravone to be an effective radioprotector against γ-irradiation-induced cellular damage in lymphocytes in vitro. Finally, edaravone pretreatment significantly reduced DNA damage in γ-irradiated lymphocytes, as measured by comet assay (% tail DNA, tail length, tail moment, and olive tail moment) (p < 0.05). Thus, the current study indicates that edaravone offers protection from radiation-induced cytogenetic alterations.     

Binding of stimulated human peripheral blood lymphocytes to Sepharose-concanavalin A is not reversed by methyl-α-mannoside

Concanavalin A (con A) bound to Sepharose beads stimulates human peripheral blood lymphocytes and as with soluble con A, DNA synthesis can be prevented by the addition of methyl-α-mannoside (MAM) 1 hr after exposure to mitogen. In contrast to the response of cells stimulated with soluble con A, addition of MAM 24 hr after the start of incubation with Sepharose bound mitogen does not prevent a second round of DNA replication as determined in bromodeoxyuridine density transfer experiments indicating that MAM does not dissociate the Sepharose-con A responding cell complex. We infer that within 24 hr, lymphocytes develop associations with con A-Sepharose beads at non MAM dissociable sites.     

Interaction of bilirubin with human lymphocytes and granulocytes — the effect on bilirubin metabolism

An in vitro degradation of bilirubin by isolated human granulocytes and lymphocytes is described. Changes in the bilirubin concentration during interaction with these cells were determined spectrophotometrically. The dependence of the reaction velocity on the original bilirubin concentration followed an adsorption isotherm, typical of enzyme processes with a Km of 79 microM at a cell concentration of 500/microL. The primary event is the adsorption of bilirubin to the cell surface and, in addition, its detoxication. Cyanide and sonic treatment of cells inhibit the reaction, salicylic acid enhances the cell activity. The bilirubin-detoxicating effect is discussed with respect to the therapy of hyperbilirubinaemia in neonates.     

Expression of CD3 complexes by native and UV-irradiated T lymphocytes from human blood upon treatment with Leukocytic α-interferon

The influence of leukocytic α-interferon on the expression of CD3 complexes by native and UV-irradiated T cells from human blood has been studied. Irradiation at doses of 151–906 J/m² increased the quantity of CD3 complexes on the surface of their membranes, whereas a dose of 1359 J/m² decreased it. Subsequent incubation with the cytokine (0.01–100 IU/ml) could level off the stimulatory effect of “therapeutic” UV doses but reversed the CD3-suppressive effect of the maximal UV dose. These data may be important with regard to combined therapy.     

No inhibition of interferon γ release in human lymphocytes by Ciamexone

Summary In previous experiments Ciamexone, derivative of 2-cyan-aziridine, was able to influence T-cell-mediated regulatory mechanisms but seemed to have no or only little effect on T cell effector mechanisms. On the basis of these observations Ciamexone seems to be a highly selective immunosuppressive agent. In order to evaluate further possible mechanisms of Ciamexone it was the aim of our investigation to study its influence on interferon (IFN) production in phytohaemogglutinin (PHA)-stimulated T lymphocytes of 15 tumour patients and 12 healthy reference subjects. The IFN concentration of the cell supernatant was measured using an enzyme-linked immunosorbent assay. When the cells were stimulated with PHA at 7.5 µg/ml the IFN concentration rose to significantly different values in the reference group (1.0 ng/ml) as compared to the tumour patients (0.4 ng/ml) (P <0.05). An addition of Ciamexone (at any of the concentrations administered) to PHA stimulation of peripheral blood mononuclear cells (PBMC) showed no influence on the IFN release in either test group. The influence of hydrocortisone on the stimulation of PBMC with PHA resulted in a dose-dependent suppression of IFN production in both test groups, again with significant differerences between them. The IFN concentration was 0.95 ng/ml in the reference group and 0.2 ng/ml in the tumour patients when 0.01 µg/ml hydrocortisone was added (P <0.05). At 10 µg/ml hydrocortisone suppressed IFN production completely in both groups. Our results corroborate those investigations that showed no influence of the compound on T cell effector mechanisms. The attenuation of humoral immunophenomena, however, suggest a very specific point of action within the immune system by Ciamexone.     

Changes in human γ-globulin preparations during storage

Во время хранения, человека γ-глобулин препараты протеолиза проходить медленно, в результате в составе двух фракций сплит. Один из них (γx) медленнее, чем обычно γ-глобулин, в то время как другие (γи) больше быстрыми темпами. Темпы разрушения в плазме подготовка охватывает несколько лет, тогда как в препаратов, полученных в результате haemolysed и плацентарной материала это несколько месяцев. Аналогичная разбивка была искусственно вызванной в плазмин, trypsin и papain. Определенный артикль изменения могут быть обнаружены путем immunoelectrophoresis, но электрофореза в Агар и высокоскоростного центрифугирования также дают приблизительную картину состояния подготовки. Определенный артикль γx дроби могут быть восстановлены в immunoelectrophoretically чистом состоянии путем осадков с сульфата аммония (более 50% насыщения), или с Zn₂₊ солей (в supernatant жидкости составляет более 50 мм концентрация). Определенный артикль γ_и фракция crystallizes из решений с низкой ионной силы в виде минуту, игла-как, оптически неактивных кристаллов. Причины изменений в соответствующую препаратов и биохимических и Иммунохимические аспекты с учетом явления рассматриваются.     

Helicobacter pylori induces activation of human peripheral γδ+ T lymphocytes

Helicobacter pylori is a gram-negative bacterium that causes gastric and duodenal diseases in humans. Despite a robust antibody and cellular immune response, H. pylori infection persists chronically. To understand if and how H. pylori could modulate T cell activation, in the present study we investigated in vitro the interaction between H. pylori and human T lymphocytes freshly isolated from peripheral blood of H. pylori-negative donors. A direct interaction of live, but not killed bacteria with purified CD3+ T lymphocytes was observed by microscopy and confirmed by flow cytometry. Live H. pylori activated CD3+ T lymphocytes and predominantly γδ+ T cells bearing the TCR chain Vδ2. Upon interaction with H. pylori, these cells up-regulated the activation molecule CD69 and produced cytokines (such as TNFα, IFNγ) and chemokines (such as MIP-1β, RANTES) in a non-antigen-specific manner. This activation required viable H. pylori and was not exhibited by other gram-negative bacteria. The cytotoxin-associated antigen-A (CagA), was at least partially responsible of this activation. Our results suggest that H. pylori can directly interact with T cells and modulate the response of γδ+ T cells, thereby favouring an inflammatory environment which can contribute to the chronic persistence of the bacteria and eventually to the gastric pathology.     

Influence of the human blood serum on contractility and β-adrenoreactivity of the isolated human myocardium

Influence of adrenaline (10⁻⁹ to 10⁻⁴ g/ml) on the contraction amplitude caused by electrostimuli (1Hz, 5 ms, 25–30 V) and inotropic and adrenomodulation activities of blood serum of nonpregnant women (at dilutions of 1 : 10 000, 1 : 1000, 1 : 500, 1 : 100, 1 : 50, 1 : 10, and 1 : 5) have been studied. The study has been carried out on isolated myocardium strips of the right atrial auricle that were taken from 43 patients with ischemic illness of the heart and 9 patients with valvular heart diseases of various etiologies upon venous cannula insertion during an aortocoronary bypass. Direct dependence of the contraction amplitude on the cardiac output according to Teicholz has been found. This meant that strips of the right atrial auricle reflected the contractility of the left ventricle myocardium. Adrenaline has been shown to dose-dependently increase the amplitude of evoked contractions in the concentration interval from 10⁻⁷ to 10⁻⁶ g/ml and had no influence from 10⁻⁹ to 10⁻⁸ g/ml (dissociation constant, 2 × 10⁻⁷ g/ml), which proved a decrease in the β-adrenoreceptor’s (β-AR) activation. Blood serum in a dilution range from 1 : 10 000 to 1 : 50 had no effect on the contraction amplitude, but an enhanced effect has been found in a dilution range from 1 : 10 and 1 : 5. The presence of the endogenous activator of myocytes contractility (EAMC) has explained this enhanced effect. The β-adrenomodulation activity of blood serum has been explained by the presence of the endogenous sensitizer of β-AR (ESBAR) and the endogenous blocker of β-AR (EBBAR). The ESBAR activity of blood serum (dilutions: 1 : 1000, 1 : 500, 1 : 100, and 1 : 50) has been found in experiments with a subthreshold adrenaline concentration (10⁻⁸ g/ml). ESBAR (dilutions: 1 : 50 and 1 : 10) and EBBAR (dilution 1 : 500) activities of blood serum have been found in experiments with the maximum effective concentration of adrenaline (10⁻⁶ g/ml). Therefore, blood serum endogenous modulators of β-adrenergic reactivity, ESBAR and EBBAR, can modulate the activation of β-AR of human cardiomyocytes. These prove the prospects of the ESBAR analogue application in cardiology.     

Are cyclic nucleotides involved in the initiation of mitogenic activation of human lymphocytes?

In order to obtain more insight into the possible role of cyclic AMP or cyclic GMP in modulating the initial cellular processes following activation of lymphocytes, we measured the effects of the T-cell mitogen concanavalin A and other substances including hormones on the cyclic nucleotide levels in human peripheral blood lymphocytes. The enzyme activities of the corresponding nucleotide cyclases, adenylate cyclase and guanylate cyclase were measured in both isolated plasma membranes or the cytosol of resting or concanavalin A stimulated rabbit thymocytes. Concanavalin A in a mitogenic concentration of about 5-10 micrograms/ml caused small, but consistent increases in cAMP but no changes in cGMP levels during the first hour of activation. Concomitantly, the specific activity of plasma membrane-bound adenylate cyclase was always increased at least 1.5-fold 30 min after stimulation of rabbit thymocytes with concanavalin A, but no effect could be detected on the specific activities of plasma membrane-bound or soluble guanylate cyclase. At high, supraoptimal concentrations of concanavalin A (more than 20 micrograms/ml) cAMP levels dramatically increased in human lymphocytes within minutes, but cGMP levels again were unaffected. Forskolin and beta-adrenergic hormones elevated cAMP in human lymphocytes, whereas cGMP levels were increased by the addition of sodium nitroprusside or alpha-adrenergic hormones. Sodium nitroprusside, in concentrations which elevated cGMP in human lymphocytes, had no influence on the incorporation of [3H]uridine into RNA of resting or concanavalin A stimulated human lymphocytes. Addition of forskolin resulted in an increase of cAMP levels and a dose-dependent decrease of [3H]uridine incorporation into RNA of concanavalin A-stimulated lymphocytes with no effect on resting lymphocytes. The data suggest that cGMP does not play a role in the initial phase of mitogenic activation of lymphocytes, whereas cAMP may be involved in the blast transformation process as an inhibitory signal.     

Chromosome aberrations and response to γ-ray challenge in lymphocytes of workers exposed to 1,3-butadiene

An integrated population monitoring study was initiated to investigate whether occupational exposure to current low levels of butadiene is mutagenic to workers. Ten exposed workers (mean production area concentration of 3.5 ppm) and 10 matched plant controls(mean exposure to 0.03 ppm) were selected and blood samples were collected for our study. The standard cytogenetic assay was used to determine chromosome aberration frequencies. In addition, a challenge assay was used to determine response to γ-rays as an indication of DNA repair deficiencies. In the latter assay, cells were exposed to γ-rays at the G1 phase of the cell cycle in vitro and the frequencies of chromosome aberrations in the first post-irradiation metaphase cells were quantitated. Based on results of the cytogenetic assay, the exposed group had a higher frequency of cells with chromosome aberrations and higher chromatid breaks per 100 cells compared with the control. However, the difference was not significant (p > 0.1). With the challenge assay, the exposed group had a higher frequency of aberrant cells (p < 0.04), chromatid breaks (p < 0.05), deletions (p < 0.07), and dicentrics (p < 0.02) than the controls. In addition, the dicentric frequencies from workers were significantly correlated with the presence of a butadiene metabolite [1,2-dihydroxy-4-(N-acetyl-cysteinyl-S)butane] in urine with a correlation of coefficient of 0.6 (p < 0.01). Two outliers were identified and our interpretation of their responses will be discussed. This study indicates that the workers had exposure-induced mutagenic effects. Together with the observation of gene mutation in a subset of the present population, this study indicates that the current occupational exposure to butadiene may not be safe to workers.     

Are cardiovascular and sympathoadrenal effects of human "new pressor protein" preparations attributable to human coagulation beta-FXIIa?

"New pressor protein" (NPP) derived from normal human plasma is an extra renal enzyme that shares strong sequence homology with human coagulation beta-FXIIa. Under our bioassay conditions, human NPP (10-20 microl plasma equivalent/ approximately 300 g rat iv) can raise the systolic blood pressure (SBP) by 40-50 mmHg, the diastolic blood pressure (DBP) by 15-20 mmHg, and the heart rate (HR) by 70-90 beats/min. Plasma epinephrine (of adrenal medullary origin) and norepinephrine rise by about 50- and 10-fold, respectively. Because beta-FXIIa is not normally associated with pressor properties, we endeavored to substantiate that the hypertensive effects of impure NPP preparations used in our experiments are attributable to their content of beta-FXIIa. We carried out comparisons with highly purified (>90%) commercial human beta-FXIIa and found that by gel filtration (Sephadex G-100 and G-75), NPP bioactivity appeared in the approximately 30-kDa elution zone, consistent with the molecular mass of beta-FXIIa. Retention time using fast-protein liquid chromatography anion exchange chromatography was identical. Molecular mass and comigration were confirmed by SDS-PAGE gel electrophoresis, and the recovered approximately 30-kDa protein bands yielded beta-FXIIa fragments identified by mass spectrometry. Matched doses of the NPP preparations produced dose-response curves very similar to those elicited by beta-FXIIa with respect to increments of SBP, DBP, and HR, whereas plasma catecholamine increments were generally comparable. We propose that beta-FXIIa is substantially, if not exclusively, responsible for the observed effects of our NPP preparations and that this points to a novel axis connecting the FXII coagulation cascade and the sympathoadrenal gland to other cardiovascular regulatory mechanisms.