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At least 19 recordsLinked to original sources

PubMed2026

Expression and mutation characteristics of mitochondrial genes in PBMCs of SLE patients: Implications for SLE pathogenesis.

This study aimed to investigate mitochondrial gene mutations and expression in peripheral blood mononuclear cells (PBMCs) of systemic lupus erythematosus (SLE) patients, focusing on MT-ND5, and assess expression changes under lipopolysaccharide (LPS), tumor necrosis factor-α (TNF-α), and dexamethasone stimulation. Peripheral blood was collected from female SLE patients. Mitochondrial DNA (mtDNA) from PBMCs was sequenced using the HiSeq PE150 platform. Quantitative reverse transcription PCR and western blotting were used to evaluate mRNA and protein expression of the most frequently mutated mitochondrial genes. Cultured PBMCs were treated with LPS, TNF-α, or dexamethasone to examine regulatory effects. A total of 589 mtDNA mutation sites were detected in SLE patients. Among 13 protein-coding genes, MT-ND5, MT-CYB, MT-CO1, MT-ND4, and MT-CO3 exhibited the highest mutation frequencies. Expression analysis revealed significantly reduced mRNA and protein levels of these genes in SLE PBMCs compared with controls, with further decreases after stimulation with LPS, TNF-α, or dexamethasone. SLE PBMCs display extensive mitochondrial mutations and downregulation of key genes, particularly MT-ND5. Inflammatory and therapeutic stimuli exacerbate this suppression, suggesting mitochondrial dysfunction contributes to SLE susceptibility and progression.

Humans↗

PubMed2026

Characterization of DNA methylation in PBMCs and donor-matched iPSCs shows age-related methylation is reset during stem cell reprogramming.

DNA methylation is an important epigenetic mechanism that helps define and maintain cellular functions. It is influenced by many factors, including environmental exposures, genotype, cell type, sex, and aging. Since age is the primary risk factor for developing neurodegenerative diseases, it is important to determine if age-related DNA methylation is retained when cells are reprogrammed to an induced Pluripotent Stem Cell (iPSC) state. Here, we selected peripheral blood mononuclear cells (PBMCs; n = 99) from a cohort of diverse and healthy individuals enrolled in the Genetic and Epigenetic Signatures of Translational Aging Laboratory Testing (GESTALT) study to reprogram to iPSCs. After reprogramming, the resulting iPSCs were evaluated for DNA methylation signatures to determine if they reflect the confounding factors of aging and environmental effects. Data from genome-wide DNA methylation arrays in both cell types showed that age-related methylation measured by epigenetic clocks is largely reset to an early methylation age after reprogramming of PBMCs to iPSCs. We further examined the epigenetic age of each cell type using an Epigenome-wide Association Study (EWAS) and identified a set of methylation Quantitative Trait Loci in each cell type. Our results show that age-related DNA methylation is largely reset in iPSCs, and each cell type has a unique set of methylation sites that are modified by population-level genetic variation.

DNA Methylation↗

PubMed1991

The role of prostaglandin E2 in immune suppression following injury.

It has been thought for some time that prostaglandin E2 (PGE2) released from activated monocytes/macrophages may contribute to the suppression of immunity seen after burns and major injury because PGE2 inhibits the activation of T lymphocytes. To clarify this issue, we studied 15 patients with total body surface area burns of 20% to 90% (mean, 48%). Peripheral blood mononuclear cells (PBMC) were obtained from these patients one to two times each week for 1 month after burn and were stimulated with the T-cell mitogen phytohemagglutinin (PHA). On 14 occasions the PBMCs from eight patients were significantly suppressed (30% or more) in their response to PHA (suppressed [sup] burn) as compared with PBMCs from normal controls. In 38 instances PBMCs from 12 patients were not significantly suppressed in PHA (nonsuppressed [nonsup] burn). Sup burn PBMCs and control PBMCs were cultured with or without the addition of the cyclooxygenase (CO) inhibitor indomethacin (Indo, 1 microgram/mL) and studied for PHA response and the production of the stimulatory cytokine interleukin-2 (IL-2). Indo partially restored the PHA response of sup burn PBMCs to normal. Sup burn PBMCs also were deficient in production of IL-2. Indo increased IL-2 production by sup burn PBMCs significantly more (160% +/- 20%, p less than 0.005) than control (57% +/- 5%) and nonsup PBMCs (67% +/- 8%). Next inhibition of the PHA response of PBMCs from 12 burn patients and 17 controls was studied by exogenous PGE2. At all time periods after burn injury, patients' PBMCs were significantly more sensitive to inhibition by PGE2 (50% inhibition at 10(-8) mol/L [molar] PGE2) than PBMCs from normal controls (50% inhibition at 10(-6) mol/L PGE2) with maximum sensitivity occurring 8 to 14 days after injury. Peripheral blood mononuclear cells from patients with more than 40% burns were significantly (p less than 0.05) more sensitive to PGE2 than those from patients with lesser burns. Interleukin-2 was added to cultures of sup burn PBMC, nonsup burn PBMC, and controls containing 10(-7) mol/L PGE2. Interleukin-2 totally reversed PGE2 inhibition of the PHA response in PBMC from both controls and burn patients. Because endotoxin leak from the gut has been implicated as a trigger for a number of the metabolic and immunologic abnormalities following injury, the authors looked for the effect of a bolus infusion of Escherichia coli endotoxin (Endo, 4 ng/kg) in seven normal healthy volunteers on the response of PBMC to PHA and on the production of PGE2 and IL-2.(ABSTRACT TRUNCATED AT 400 WORDS)

Adolescent↗

PubMed1992

Transcription of bovine leukemia virus in peripheral blood cells obtained during early infection in vivo.

Bovine leukemia virus (BLV) is transcriptionally silent in most circulating peripheral blood mononuclear cells (PBMCs) of animals with well-established infections. Using PBMCs from a newly infected sheep, we asked whether viral transcription proceeded differently during the initial months of infection, when the prevalence of BLV-infected cells and the host's immunological response change markedly. Shortly after being injected with BLV, the animal displayed a characteristic, transient increase in PBMCs that transcribed BLV when cultured. Even when transcriptionally competent PBMCs were most prevalent (1.2%), only rare cells in the circulation (1 in 50,000) contained enough BLV transcripts to be identified readily by in situ hybridization. However, at one point several weeks later, some PBMCs appeared to contain small amounts of BLV RNA as soon as they had been purified from blood. Throughout this period, BLV-transcribing PBMCs greatly outnumbered virus-producing cells, which were counted using a new infectious centers assay. Its viscous medium reduced cell to cell contact among PBMCs, enabling increased detection of BLV-producing cells at a time when virus-specific killer cells might be active. Early infection was polyclonal, and most infected PBMCs transcribed BLV upon being cultured. By 2 months after infection, provirus-containing cells were as abundant as they had been earlier, but few cells transcribed BLV. These results suggest that BLV-infected cells are more easily stimulated to transcribe the provirus and produce infectious virus during the early months of a new infection.

Animals↗

PubMed1992

Decreased interferon gamma and increased interleukin-4 production in atopic dermatitis promotes IgE synthesis.

The mechanism(s) responsible for increased IgE synthesis in atopic dermatitis (AD) are unknown, but they may be related to either decreased interferon gamma (IFN-gamma) and/or increased interleukin (IL)-4 production. In this study we examined peripheral blood mononuclear cells (PBMCs) from 21 patients with AD, six patients with psoriasis, and 22 nonatopic healthy controls for IFN-gamma and IL-4 production after stimulation with concanavalin A (Con A). The Con A-induced proliferative response of AD PBMCs was similar to the response of healthy controls (p = 0.9). After mitogen stimulation, however, AD culture supernatants contained significantly less IFN-gamma (p = 0.001) but increased IL-4 (p = 0.001) compared with supernatants from nonatopic controls. In contrast, PBMCs from patients with psoriasis produced normal levels of IFN-gamma and IL-4 in vitro. Since IL-4 is known to decrease IFN-gamma synthesis, we examined the effect of neutralizing anti-IL-4 on IFN-gamma production. Anti-IL-4 significantly increased IFN-gamma production in patients with AD (p = 0.008) and nonatopic controls (p = 0.02) but did not normalize IFN-gamma production by AD PBMCs. Supernatants from AD PBMCs, but not supernatants from nonatopic PBMCs, induced IgE synthesis in PBMCs from nonatopic donors (p = 0.02). When an anti-IFN-gamma receptor antibody, which blocks cellular binding of IFN-gamma, was added to supernatants from nonatopic controls their capacity to induce IgE synthesis was significantly greater (p = 0.03). These results demonstrate an imbalance of IL-4 and IFN-gamma production, which may contribute to increased IgE synthesis in AD.

Dermatitis, Atopic↗

PubMed1992

Demonstration of woodchuck hepatitis virus infection of peripheral blood mononuclear cells by flow cytometry and polymerase chain reaction.

Peripheral blood mononuclear cells (PBMCs) from 10 woodchuck hepatitis virus (WHV)-infected woodchucks were examined for the presence of WHV surface (WHs) and core (WHc) antigens (WHsAg and WHcAg) by cytofluorometry using fluorescein isothiocyanate-conjugated anti-WHs and anti-HBc-purified immunoglobulins from woodchuck and human sera. The presence of viral DNA and RNA was detected in the serum and PBMCs from the same blood samples by polymerase chain reaction (PCR) with two primer sets located in the S and C genes of the WHV genome. Seven animals were found positive for both WHsAg and WHcAg on the surface of PBMCs: four WHV-chronic carriers, two WHsAg-positive animals with acute WHV infection, and one woodchuck which was bled during the incubation phase of WHV infection and which became WHsAg-positive only 1 month later. Sixteen to 71% of the studied leukocyte population expressed WHsAg with a low density of expression whereas 7 to 72% expressed WHcAg with a high density of expression. Only two cases were positive for WHsAg without WHcAg on PBMCs, one WHV chronic carrier and one anti-WHs-positive animal. All woodchucks positive for WHcAg and/or WHsAg by cytofluorometry were positive also for WHV DNA and RNA in PBMCs by PCR. The tenth animal was found negative for both viral antigens as well as for WHV DNA and RNA in PBMCs despite the presence of persistent viral DNA in the serum as detected by PCR. Five healthy woodchucks devoid of WHV serological markers served as negative controls. These results obtained with a novel approach further confirm, in the woodchuck model, that a significant proportion of PBMCs are probably permissive for WHV replication. The possible immunopathogenic implications of the phenomenon are discussed.

Animals↗

PubMed1990

Decrease in interferon-gamma production by peripheral blood mononuclear cells in patients with uterine cervical cancer.

The interferon-gamma (IFN-gamma) productivity of peripheral blood mononuclear cells (PBMCs) was examined in 30 patients with uterine cervical cancer. The patients under 50 years of age had decreased IFN-gamma production compared with the age-matched controls. The IFN-gamma productivity in the patients over 50 years of age was decreased as well as in the age-matched controls. The proportion of monocytes in PBMCs did not correlate with the IFN-gamma productivity. The prostaglandin E2 (PGE2) productivity of PBMCs increased with the progress of cancer. PGE2 inhibited the IFN-gamma production by PBMCs, and the sensitivity of PBMCs to PGE2 was increased in the patients and controls over 60 years of age. The addition of indomethacin resulted in an increase in IFN-gamma production by PBMCs. These results suggest that the increased production of PGE2 and/or increased sensitivity to PGE2 are responsible for the decreased IFN-gamma production in patients with cervical cancer.

Adult↗

PubMed1992

Effects of cytokines on beta-adrenoceptor function of human peripheral blood mononuclear cells and guinea pig trachea.

In asthma, a beta-adrenoceptor dysfunction may be the consequence of an active disease state rather than a fundamental abnormality. In the present study the possible involvement of T lymphocytes in beta-adrenergic impairment was investigated by studying the effects of lymphocyte-derived mediators of beta-adrenoceptor function of human peripheral blood mononuclear cells (PBMCs) and guinea pig trachea. Supernatants of phytohemagglutinin- or concanavalin A-activated PBMCs from either persons with asthma or healthy persons inhibited isoprenaline stimulated cyclic adenosine 3',5'-monophosphate (cAMP) production of PBMCs after 20 hours of preincubation. These supernatants also inhibited beta-adrenoceptor function of PBMCs from patients with asthma to the same extent. The isoprenaline stimulated cAMP production of PBMCs was not altered after a 2-hour preincubation period with human interleukin-1 (IL-1), IL-2, IL-3, IL-4, granulocyte-macrophage colony-stimulating factor (GM-CSF) and interferon (IFN-gamma). In contrast, after 20 hours of preincubation, stimulated cAMP production of PBMCs was significantly diminished, with 63% by IL-1 (40 U/ml, p less than 0.01), with 36% by IL-2 (100 U/ml, p less than 0.05), with 37% by IFN-gamma (1000 U/ml, p less than 0.05), and with 21% by GM-CSF (100 U/ml, p less than 0.05). Preincubation of guinea pig tracheal segments with IL-1, IL-2, IL-4, or GM-CSF during 1 or 3 days did not affect the EC50 values or the maximal relaxation of isoprenaline dose response curves.

Animals↗

PubMed1992

Prolactin synthesized and secreted by human peripheral blood mononuclear cells: an autocrine growth factor for lymphoproliferation.

Prolactin has been shown to have an immunoregulatory role in the rodent immune response. A prolactin-like molecule has also been found in mouse splenocytes and a human B-lymphoblastoid cell line. We have evaluated whether human peripheral blood mononuclear cells (PBMCs) synthesize and/or secrete prolactin. We used the polymerase chain reaction (PCR) to generate a 276-base-pair prolactin product from human PBMCs, and Southern blot analysis confirmed that it was related to prolactin. Western blotting using a polyclonal antibody to prolactin indicated that cell extracts prepared from human PBMCs contained a high molecular mass (60-kDa) immunoreactive prolactin. To determine whether this PBMC prolactin was being secreted, we developed a highly sensitive and specific hormonal enzyme-linked immunoplaque assay. With this assay, we were able to detect human prolactin secretion from concanavalin A (Con A)- or phytohemagglutinin-stimulated PBMCs but not from unstimulated PBMCs. We next sought to determine whether this secreted prolactin could function as an autocrine growth factor in lymphoproliferation. We observed that anti-human prolactin antiserum significantly inhibited human PBMC proliferation in response to Con A or phytohemagglutinin. We conclude that a prolactin-like molecule is synthesized and secreted by human PBMCs and that it functions in an autocrine manner as a growth factor for lymphoproliferation.

Base Sequence↗

PubMed1988

Newcastle disease virus as an antineoplastic agent: induction of tumor necrosis factor-alpha and augmentation of its cytotoxicity.

The oncolytic strain 73-T of Newcastle disease virus (NDV) has been reported to be beneficial in the treatment of cancer patients, but little is known about its mechanism of action. In this study, NDV strain 73-T and a wild-type isolate of NDV were found to be potent inducers of tumor necrosis factor (TNF) production by both human peripheral blood mononuclear cells (PBMCs) and rat splenocytes. Antibody inhibition experiments identified TNF-alpha as the major species of TNF induced by NDV in PBMCs. The effect of recombinant human TNF-alpha (rHuTNF-alpha) on human cancer cells was then examined. Neither rHuTNF-alpha nor supernatants from NDV-stimulated PBMCs were cytotoxic toward the TNF-resistant human malignant melanoma cell line MEL-14. However, when MEL-14 cells were treated with NDV strain 73-T, both rHuTNF-alpha and supernatants from NDV-stimulated PBMCs killed 48% and 55%, respectively, of these tumor cells. Treatment with NDV also conferred TNF susceptibility to the TNF-resistant human malignant melanoma cell line MEL-21 and the human myelogenous leukemia cell line K562. In contrast to its enhanced cytotoxicity toward NDV-treated cancer cells, rHuTNF-alpha had no effect on NDV-treated normal human PBMCs proliferating in response to concanavalin A. These results suggest two important mechanisms for the antineoplastic activity of NDV: (a) induction of TNF-alpha secretion by human PBMCs and (b) enhancement of the sensitivity of neoplastic cells to the cytolytic effects of TNF-alpha.

Antibodies↗

PubMed1992

Intracellular zidovudine (ZDV) and ZDV phosphates as measured by a validated combined high-pressure liquid chromatography-radioimmunoassay procedure.

In vitro studies of zidovudine (ZDV) phosphorylation may not accurately reflect the in vivo dose-response relationship, which is crucial to determining the relationship between ZDV exposure, efficacy, and toxicity. However, measurement of ZDV phosphorylated anabolites in peripheral blood mononuclear cells (PBMCs) from ZDV-treated human immunodeficiency virus (HIV)-infected patients would be extremely useful in the more appropriate utilization of ZDV in the treatment of HIV infection. We developed a specific and sensitive combined high-pressure liquid chromatography (HPLC)-radioimmunoassay (RIA) procedure for the determination of ZDV, ZDV-monophosphate, ZDV-diphosphate, and ZDV-triphosphate in PBMCs taken from ZDV-treated HIV-infected patients. ZDV and its anabolites were extracted from washed, Ficoll-Paque-isolated PBMCs and then separated by HPLC using a strong anion-exchange column. The anabolites were then hydrolyzed to ZDV with acid phosphatase. ZDV was then measured by using a modified commercially available RIA protocol. Our method was validated by measuring [3H]ZDV anabolites generated in Molt-4 cells radioisotopically and simultaneously by the combined HPLC-RIA procedure. The ZDV determinations correlated well (r2 = 0.97) over the range of 0.037 to 5.2 pmol (10 to 1,400 pg) per assay tube. Furthermore, we defined the stability of ZDV anabolites during ficoll isolation and the recovery after extraction and cleanup. We then measured intracellular parent ZDV and its phosphorylated anabolites in PBMCs from six ZDV-treated HIV-infected patients (PBMCs were taken 2 h after a 300-mg oral dose). The mean concentrations ( +/- standard deviations) of parent and of mono-, di-, and triphosphates were 0.15 +/- 0.08, 1.4 +/-, 0.082 +/- 0.02, and 0.081 +/- 0.03 pmol/10(6) PBMC, respectively (one pmol/10(6) PBMC represents a concentration of approximately 1 microm). Concurrent serum ZDV concentrations were between 1.3 and 7.1 microm. This method should provide a useful tool for evaluating in vivo pharmacokinetics of ZDV anabolites in PBMCs and possibly other cell types, even at the low doses of ZDV currently administered therapeutically.

Cells, Cultured↗

PubMed1989

Specific binding of human alpha interferon to high-affinity cell-surface binding sites on peripheral blood mononuclear cells.

To characterize receptors for alpha interferon (IFN-alpha) on human cells, we studied the binding of radioiodinated recombinant DNA-derived human IFN-alpha to human peripheral blood mononuclear cells (PBMCs) from normal individuals and from patients with chronic type B hepatitis. At 1 degree C, binding reached equilibrium after 2 to 3 hours of incubation, and saturation of specific binding occurred at a concentration of approximately 4000 fmol/ml. Binding of labeled IFN-alpha was specific; it was inhibited by an excess of unlabeled IFN-alpha or IFN-beta but not by cholera toxin or IFN-gamma. Scatchard analysis of binding data yielded for normal PBMCs an apparent dissociation constant (Kd) of 1.54 +/- 0.49 x 10(-9) mol/L (mean +/- SD) and an apparent maximum binding capacity (Bmax) of 7.35 +/- 1.22 x 10(-11) mol/L. Corresponding values for patients with chronic type B hepatitis who had not received treatment were similar, suggesting that such patients should respond normally to endogenous interferon. Analysis of data on the binding of labeled IFN-alpha to normal PBMCs from experiments in which a high specific activity ligand or subpopulations of PBMCs had been used revealed that receptors for IFN-alpha on PBMCs are heterogenous. In patients with chronic type B hepatitis who were receiving IFN-alpha therapy, the apparent Kd was increased (3.02 +/- 0.91 x 10(-9) mol/L) without any appreciable change in the apparent Bmax or any appreciable changes in the proportions of subpopulations of PBMCs. This decreased affinity induced by IFN-alpha treatment does not necessarily reflect an effect on a single binding site.(ABSTRACT TRUNCATED AT 250 WORDS)

Binding Sites↗

PubMed1988

Activation of mononuclear cells to be used for hybrid monoclonal antibody-induced lysis of human ovarian carcinoma cells.

Recently we reported that cytotoxic T-cell clones can be retargeted to unrelated tumor cells by bispecific monoclonal antibodies (MAbs), anti-CD3 and anti-ovarian carcinoma (alpha OC/TR) (Mezzanzanica et al., 1988). In the perspective of in vivo tumor immunotherapy, as an alternative to cytotoxic T lymphocytes (CTL) from T-cell clones, since human peripheral blood mononuclear cells (PBMCs) without stimulation were quite ineffective, a suitable in vitro activation method was developed to render PBMCs lytic for relevant targets in the presence of the bispecific hybrid MAb alpha OC/TR. This activation protocol was applied to PBMCs from 9 healthy donors (HD) and 6 ovarian carcinoma patients (P) and to tumor-associated lymphocytes (TAL) from 4 ovarian carcinoma P. The method consisted of in vitro stimulation with phytohemagglutinin (PHA) for 2 days, followed by culture with a low dose of recombinant human interleukin-2 (rIL-2) for 6 to 10 days. The antibody-mediated lysis of CTL from HD PBMCs was found to be specifically directed against cells expressing the relevant ovarian tumor antigen when different tumor cell lines and short-term cultures of tumor and normal cells were tested. The antibody-mediated lysis of CTL from P PBMCs or TAL was efficient both on autologous and allogeneic ovarian tumor cells, whereas no reactivity with autologous normal cells was observed and LAK activity was only evident in 1 out of 4 cases. The hybrid antibody induced cytotoxic activity of CTL from P was, however, lower than that of CTL from HD.

Antibodies, Monoclonal↗

PubMed1988

Assessment of human immunodeficiency virus expression in cocultures of peripheral blood mononuclear cells from healthy seropositive subjects.

We have evaluated a number of methodological variables effecting the expression of human immunodeficiency virus (HIV) in cultured peripheral blood mononuclear cells (PBMCs) of 93 healthy anti-HIV-positive and 72 healthy seronegative subjects. For optimal HIV recovery, PBMCs had to be freshly separated from whole blood. Short-term freezing of purified PBMCs was practically advantageous and actually resulted in more rapid virus recovery. The minimal number of PBMCs necessary for virus expression was determined by dilutional cultures and varied from 10(2) to 10(6) cells. HIV expression was demonstrated initially at the cellular level by immunocytochemical detection of HIV core and envelope proteins using a mixture of monoclonal antibodies, subsequently confirmed by detection of viral antigens and reverse transcriptase (RT) in the culture supernatants. HIV recovery was not improved following induction with 5-iodo-2'-deoxyuridine (IUDR) and only marginally improved following depletion of the CD8+-suppressor cell population in the PBMC specimens. The overall frequency of HIV detection in cultures was 84% in healthy seropositive subjects, whereas none of the PBMCs from 72 seronegative persons yielded HIV expression.

Cells, Cultured↗

PubMed1992

Lymphocyte responses to food antigens in food sensitive patients with allergic tension-fatigue syndrome.

Scores of radioallergosorbent test (RAST) for cow's milk or buckwheat flour and proliferative responses of peripheral blood mononuclear cells (PBMCs) to bovine serum albumin and beta-lactoglobulin or buckwheat flour were measured in cow's milk or buckwheat flour sensitive patients with allergic tension-fatigue syndrome. In all 3 cow's milk sensitive patients with allergic tension-fatigue syndrome, RAST scores for cow's milk were negative or slightly positive, but PBMCs well responded to bovine serum albumin and beta-lactoglobulin, but not to ovalbumin. In a buckwheat flour sensitive patient with allergic tension-fatigue syndrome, RAST scores for buckwheat flour were negative, but PBMCs well responded to buckwheat flour, but not to ovalbumin, bovine serum albumin and beta-lactoglobulin. Conversely, in cow's milk or buckwheat flour sensitive patients with immediate allergic symptoms, RAST scores for offending foods were positive although PBMCs did not respond to offending food antigens. These results suggest that proliferative responses of PBMCs to food antigens are very useful for detection of offending foods in allergic tension-fatigue syndrome.

Adolescent↗

PubMed1991

The role of interleukin-6 in mitogenic T-cell activation: detection of interleukin-2 heteronuclear RNA by polymerase chain reaction.

It has been documented that interleukin-6 (IL-6) supports the proliferation of purified, anti-CD3-stimulated murine T cells. We found that stimulation of human peripheral blood mononuclear cells (PBMCs) with anti-CD3 induced a significant accumulation of IL-6 mRNA, indicating that antigen-mediated T-cell activation may involve IL-6 release from accessory cells. Phytohemagglutinin (PHA) had little effect upon IL-6 gene expression. In keeping with these findings, anti-IL-6 reduced but did not abolish anti-CD3-mediated proliferation of PBMCs, but had no significant effect upon PHA-stimulated proliferation. The addition of recombinant (r) IL-6 enhanced the proliferation of anti-CD3-stimulated PBMCs and increased the accumulation of IL-2 mRNA in PHA-stimulated PBMCs during the first 5 hr of culture. Nuclear run-off experiments did not reveal significant changes in IL-2 transcription in PHA plus rIL-6-treated PBMCs attempting to assume that IL-6 mediates stabilization of IL-2 mRNA. However, monitoring of partially spliced IL-2 mRNA by polymerase chain reaction revealed a clear increase in IL-2 heteronuclear RNA. Thus IL-6 increases the rate of IL-2 transcription which was not detectable by conventional in vitro transcription assays. We conclude that anti-CD3 triggers T-cell proliferation through a process that is partially but not entirely dependent upon release of IL-6. IL-6, in turn, supports IL-2 transcription. Insofar as anti-CD3 mimics antigen-triggered activation of the T-cell receptor complex, IL-6 appears to support the early immune response by augmenting antigen-triggered IL-2 gene expression.

Antibodies, Monoclonal↗

PubMed1992

Suppression of T-lymphocyte proliferation by sulphonamide hydroxylamines.

Hypersensitivity adverse drug reactions, characterized by fever and multi-organ involvement, are the most severe adverse reactions to sulphonamides. Although there is evidence that these reactions are initiated by metabolic events, these reactions appear to be propagated on an immune basis. We investigated the effect of a sulphonamide reactive metabolite, the hydroxylamine of sulphamethoxazole (SMX H/A), on the ability of T-lymphocytes to respond to stimulation with mitogens. Peripheral blood mononuclear cells (PBMCs) were collected and incubated with SMX H/A in increasing concentrations. PBMCs were then incubated with phytohaemagglutinin (PHA) and phorbol myristate acetate (PMA) or with PHA and ionomycin. T-lymphocyte proliferation was then determined by tritiated thymidine uptake. The hydroxylamine of sulphamethoxazole produced a concentration-dependent decrease in T-lymphocyte proliferation; this decrease was significant even at concentrations of hydroxylamine that were not associated with a decrease in cell viability. PBMCs incubated with SMX H/A that were washed and then added to fresh PBMCs failed to inhibit the proliferation of fresh PBMCs. The hydroxylamine of sulfamethoxazole produces profound suppression of T-lymphocyte proliferation. This suppression appears to be a direct event and does not involve the activation of suppressor cells. These findings may explain the infectious complications contributing to mortality associated with sulphonamide hypersensitivity reactions.

Cell Survival↗

PubMed1990

Lymphocyte responses to food antigens in patients with atopic dermatitis who are sensitive to foods.

The proliferative responses of peripheral blood mononuclear cells (PBMCs) to ovalbumin or bovine serum albumin in children with atopic dermatitis (AD) who are sensitive to hen's egg or cow's milk were significantly higher than responses of PBMCs of healthy children and hen's egg- or cow's milk-sensitive children with immediate symptoms. However, the percentages of positive RAST for hen's egg or cow's milk in the patients with AD were lower than percentages in the patients with immediate symptoms. In the patients with AD, there were no significant correlations between the proliferative responses of PBMCs and the RAST values. There were no significant differences of RAST scores among groups of patients having different degrees of severity of AD. The proliferative responses of PBMCs to ovalbumin or bovine serum albumin in patients with severe AD or moderate AD who were sensitive to hen's egg or cow's milk tended to be higher than responses of patients with mild AD, respectively, but there were no significant differences in those results. Taken together, the combination of RAST and the detection of proliferative responses of PBMCs to each food antigen is very useful in the diagnosis of hypersensitivity in children with AD who are sensitive to food allergens.

Animals↗