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PubMed1997

Fas and Fas ligand interaction is necessary for human osteoblast apoptosis.

We investigated the cellular and humoral interactions between peripheral blood mononuclear cells (PBMCs) and human osteoblasts, leading to apoptosis of osteoblasts. Human osteoblastic cell line MG63 and human primary osteoblast-like cells obtained from biopsy specimens were used in this study. PBMCs were isolated from healthy donors and cultured with or without stimulation by recombinant interleukin-2 followed by 12-o-tetradecanoylphorbol 13-acetate with ionomycin. Fas was functionally expressed on MG63 and primary osteoblast-like cells. Activated PBMCs expressed Fas ligand (FasL) strongly on their surface and killed MG63 and primary osteoblast-like cells. Cultured supernatants of activated PBMCs also induced apoptotic cell death of MG63 and primary osteoblast-like cells. In contrast, both unstimulated PBMCs and cultured supernatants of unstimulated PBMCs did not induce apoptosis of these cells. Furthermore, the cytotoxic effect and induction of apoptosis against MG63 and primary osteoblast-like cells by activated PBMCs and cultured supernatants were inhibited significantly by human Fas chimeric protein. Our data showed that human osteoblasts expressed Fas fuctionally and both membrane-type and soluble form FasL from activated PBMCs induced apoptosis of these cells, providing the one possible mechanism of bone loss in inflammatory diseases such as rheumatoid arthritis.

Antigens, Surface↗
PubMed2000

Spontaneous apoptosis of CD8+ T lymphocytes in peripheral blood of patients with advanced melanoma.

Peripheral blood mononuclear cells (PBMCs) obtained from patients with advanced melanoma but not from healthy individuals were found to undergo spontaneous ex vivo apoptosis upon incubation in medium. PBMCs were evaluated for evidence of apoptosis using Annexin V binding, caspase-3 activation, and DNA fragmentation (terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling). PBMCs of patients with melanoma contained a significantly higher proportion (P = 0.0027) of spontaneously apoptotic cells than PBMCs of controls after 24-h incubation in medium alone. The relative proportion of activated Fas+ and tumor necrosis factor receptor 1-positive (TNFR1+) PBMCs was significantly higher in patients with melanoma than that observed in controls. To demonstrate that the TNF family of receptors and ligands was involved in this type of apoptosis, PBMCs were incubated in the presence of agonistic anti-Fas antibody (CH-11) or TNF-alpha. The proportion of terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling-positive PBMCs undergoing spontaneous apoptosis was found to be comparable with that induced by CH-11 antibody or TNF-alpha. Three-color flow cytometry revealed that CD3+ Fas+ T cells were especially sensitive to apoptosis and were preprogrammed in vivo to die. Apoptosis occurred in all subsets of PBMCs but was significantly higher (P = 0.01) in the CD3+ CD8+ T-cell subset in patients relative to controls. In two patients with melanoma, who responded clinically to dendritic cell-based peptide vaccines, the proportion of apoptotic T cells was decreased by half after therapy. In patients who were treated previously with vaccination-based therapies, levels of T-cell apoptosis were lower than in the other melanoma patients. The observed accelerated death of T cells, which are activated and susceptible to apoptosis in patients with melanoma, may contribute to a rapid turnover of immune cells, resulting in a decreased immunocompetence.

Adult↗
PubMed2000

Characterization of Epstein-Barr virus-infected B cells in patients with posttransplantation lymphoproliferative disease: disappearance after rituximab therapy does not predict clinical response.

Post-transplantation lymphoproliferative disease (PTLD) is associated with Epstein-Barr virus (EBV). Quantitative and qualitative differences in EBV in peripheral blood mononuclear cells (PBMCs) of PTLD patients and healthy controls were characterized. A quantitative competitive polymerase chain reaction (QC-PCR) technique confirmed previous reports that EBV load in PBMCs is increased in patients with PTLD in comparison with healthy seropositive controls (18 539 vs 335 per 10(6) PBMCs, P =.0002). The average frequency of EBV-infected cells was also increased (271 vs 9 per 10(6) PBMCs, P =.008). The distribution in numbers of viral genome copies per cell was assessed by means of QC-PCR at dilutions of PBMCs. There was no difference between PTLD patients and healthy controls. Similarly, no differences in the patterns of viral gene expression were detected between patients and controls. Finally, the impact of therapy on viral load was analyzed. Patients with a past history of PTLD who were disease-free (after chemotherapy or withdrawal of immunosuppression) at the time of testing showed viral loads that overlapped with those of healthy seropositive controls. Patients treated with rituximab showed an almost immediate and dramatic decline in viral loads. This decline occurred even in patients whose PTLD progressed during therapy. These results suggest that the increased EBV load in PBMCs of PTLD patients can be accounted for by an increase in the number of infected B cells in the blood. However, in terms of viral copy number per cell and pattern of viral gene expression, these B cells are similar to those found in healthy controls. Disappearance of viral load with rituximab therapy confirms the localization of viral genomes in PBMCs to B cells. However, the lack of relationship between the change in viral load and clinical response highlights the difference between EBV-infected PBMCs and neoplastic cells in PTLD.

Adult↗
PubMedDate not supplied

Interleukin-4 inhibits the increased production of vascular endothelial growth factor by peripheral blood mononuclear cells in patients with inflammatory bowel disease.

BACKGROUND/AIMS: Vascular endothelial growth factor (VEGF), a potent angiogenic, permeability-enhancing cytokine plays an important role in tissue repair and chronic inflammatory disorders. Peripheral blood mononuclear cells (PBMCs) and the inflamed mucosa have been demonstrated to be main sources of the recently described circulating VEGF in patients with inflammatory bowel disease (IBD). There is no current information about the influence of immunoregulatory cytokines on VEGF in IBD. The present study examines the effect of interleukin-4 on the increased VEGF production of PBMCs in patients with IBD. METHODOLOGY: Unstimulated PBMCs from 17 patients with Crohn's disease, 16 patients with ulcerative colitis and 8 healthy controls were cultured with or without IL-4. VEGF production was measured in the supernatant using an enzyme-linked immunosorbent assay. RESULTS: IL-4 led to a significant reduction of the VEGF production by PBMCs of both active Crohn's disease patients (471.7 +/- 377.5 pg/mL vs. 208.2 +/- 123.2 pg/mL, P = 0.018, n = 7) and active ulcerative colitis patients (177.1 +/- 79.4 pg/mL vs. 87.4 +/- 77.2 pg/mL, P = 0.008, n = 9). IL-4 inhibited significantly the VEGF production by PBMCs of patients with inactive Crohn's disease (179.2 +/- 133.9 pg/mL vs. 87.7 +/- 56.6 pg/mL, P = 0.005, n = 10). There was no significant difference of VEGF release by PBMCs cultured with IL-4 in patients with active Crohn's disease or active ulcerative colitis compared with PBMCs cultured without IL-4 in patients with inactive disease and healthy controls (112.6 +/- 41.9 pg/mL, n = 8). CONCLUSIONS: IL-4 has been shown to reduce the increased VEGF production of PBMCs in patients with IBD to normal levels. The known defective immunosuppressive effect of IL-4 in IBD may contribute to the pathogenic cascade leading to inflammation by VEGF mediated mechanisms.

Adult↗
PubMed1999

[The significance of detection of hepatitis C virus RNA in peripheral blood mononuclear cells of patients with chronic hepatitis C].

OBJECTIVE: To determine the role of peripheral blood mononuclear cells (PBMCs) in hepatitis C virus (HCV) infection. METHODS: HCV RNA, HCV antigen and Fas antigen were detected in PBMCs of 22 patients with chronic hepatitis C, 21 renal dialysis patients with anti-HCV positive and 12 health blood donors as normal controls. All specimens were studied by electronic microscope (EM). RESULTS: (1) The positive rate of HCV RNA in PBMCs of 22 patients with hepatitis C was 77.3% (17/22). (2) EM showed that HCV particles replicated in PBMCs of the patients with HCV infection, but not in the serum of patients with negative HCV RNA and healthy controls. (3) HCV RNA were positive both in the serum and PBMCs of 8 patients with HCV particles positive and had a close relationship with HCV antigen and Fas antigen. The expression of HCV and apoptosis were found in the cytoplasm of PBMCs in these 8 patients. CONCLUSION: (1) Hepatitis C virus could replicate in PBMCs and produce infectious HCV particles. (2) HCV in PBMCs may act as the source of reinfection for HCV and lead to persistent infection and recurrence.

Adult↗
PubMed2003

Pharmacodynamic Evaluation of CCI-779, an Inhibitor of mTOR, in Cancer Patients.

CCI-779 is an ester of rapamycin and inhibitor of mammalian target of rapamycin (mTOR) currently in Phase II clinical development for the treatment of patients with cancer. CCI-779 interacts with mTOR and inhibits its kinase activity, resulting in inhibition of the mTOR-regulated translational controllers p70(s6) kinase and 4E-BP1. Ultimately, CCI-779 decreases the translation of mRNAs involved in the control of the cell cycle, resulting in cell cycle arrest. The objective of this study was to develop a method to determine the pharmacodynamic effects of CCI-779 suitable for use in clinical trials. Exposure of Raji lymphoblastoid cells to increasing concentrations of rapamycin resulted in a linear concentration-dependent inhibition of p70(s6) kinase activity, suggesting that p70(s6) kinase activity could be an appropriate marker for mTOR-interacting agents. In subsequent experiments, treatment of nude mice bearing the CCI-779 susceptible breast cancer cell line MDA-468 with a single dose of 10 mg/kg CCI-779 resulted in a >80% inhibition of p70(s6) kinase activity in peripheral blood mononuclear cells (PBMCs) 72 h after treatment. Importantly, the degree of p70(s6) kinase inhibition was identical in PBMCs and simultaneously collected tumor tissue, suggesting that the PBMCs are an adequate surrogate tissue for p70(s6) kinase activity in vivo. The intrasubject coefficient of variation of p70(s6) kinase activity measured in PBMCs collected from five healthy volunteers on days 1, 4, and 8 was 14%, indicating that p70(s6) kinase activity in PBMCs remains relatively stable over time. Finally, p70(s6) kinase activity was measured in PBMCs from nine patients with renal cell cancer treated with a single dose of 25, 75, or 250 mg of CCI-779 i.v. (three patients each). PBMCs were collected on days 2, 4, and 8 after CCI-779 treatment. In this small data set, eight of the nine patients had evidence of p70(s6) kinase activity inhibition after treatment that was independent of the administered dose. There was a significant linear association between time to disease progression and inhibition of p70(s6) kinase activity 24 h after treatment. In conclusion, these results indicate that the pharmacodynamic effects of CCI-779 can be determined using a p70(s6) kinase assay in PBMCs. This assay is currently being incorporated in Phase I and II studies with CCI-779 to determine its relationship with dose and plasma concentration of the agent and its value as a predictor of treatment efficacy.

Animals↗
PubMed2003

[The significance of activation-induced cell death (AICD) in pathogenesis of hepatitis B].

OBJECTIVE: To explore the significance of activation-induced cell death (AICD) in pathogenesis of hepatitis B. METHODS: Peripheral blood mononuclear cells (PBMCs) were isolated from 10 healthy blood donors. PBMCs from one person were divided into two samples. One sample was incubated with the HBV-DNA positive serum. The other was incubated with the serum of healthy person (HBV-DNA negative serum). After 72 hours incubation, the apoptosis of the PBMCs was assayed by the method of propidium iodide (PI) staining with flow cytometry. PBMCs were isolated from 14 patients with chronic hepatitis B, 6 patients with chronic severe hepatitis B and 10 healthy blood donors. The PBMCs were incubated with PHA-P. After 72 hours incubation, the apoptosis of the PBMCs was assayed by the method of PI staining with flow cytometry. RESULTS: The apoptotic rate of PBMCs incubated with HBV-positive serum was significantly higher than that with the serum of normal persons [(39.56 +/- 7.03)% vs (27.57 +/- 7.78)%, P < 0.02]. The apoptotic rate of PBMCs of patients with chronic hepatitis B (30.57 +/- 13.43%) was significantly higher than that of healthy blood donors [(11.45 +/- 5.27)%, P < 0.01] and higher than that of the patients with chronic severe hepatitis B [(13.59 +/- 6.44)%, P < 0.01]. CONCLUSION: HBV infection induces apoptosis of PBMC. AICD may be one of the important mechanisms of peripheral immune tolerance in HBV chronic infection.

Adult↗
PubMed2003

[Effect of IL-18 on peripheral blood monocytes from chronic hepatitis B patients].

OBJECTIVES: To explore the effect of IL-18 on peripheral blood monocytes (PBMCs) from chronic hepatitis B (CHB) patients and HBV DNA released by HepG2.2.15 cells, which were transfected with the gene of HBV. METHODS: PBMCs were isolated from 25 healthy persons and 25 CHB patients, which were co-cultured with HBcAg and IL-18 at different concentrations for 72 hours. The level of IFN-gamma in the culture supernatant of PBMCs was determined by ELISA. One patient' PBMCs were co-cultured for 96 hours with various concentrations of IL-18 and HepG2.2.15 cells which had been cultured for 24 hours, the supernatant was collected to detect HBV DNA level by PCR. RESULTS: When PBMCs were stimulated by HBcAg and IL-18 at various concentrations, the levels of supernatant IFN-gamma in the CHB group were much higher than those in the normal control group (at 0.2ng/ml: t=11.7, P<0.01; at 1.0ng/ml: t=16.19, P<0.01; at 5.0ng/ml: t=20.12, P<0.01), especially when the PBMCs were stimulated by HBcAg, IL-18 and IL-12 (1313.20pg/ml+-187.76pg/ml vs. 390.75pg/ml+-43.23pg/ml, t=23.94, P<0.01). The IFN-gamma level in the patients who were stimulated by HBcAg alone was much lower than the levels in the patients who were stimulated by HBcAg and IL-18 at various concentrations, and which were lower than those in the patients stimulated by HBcAg, IL-12 and IL-18 at the same concentrations (light: t=2.2, P<0.05; moderate: t=2.97, P<0.05). The HBV DNA content in the supernatant of co-cultivation with HepG2.2.15 cells and PBMCs was much higher than that of the two kinds of cells stimulated by HBcAg and IL-18 at various concentrations or HBcAg, IL-18 and IL-12/IFN-a1b. CONCLUSION: IL-18 can improve the PBMCs from CHB patients to produce a great deal of IFN-gamma, so it has a good application prospect in two aspects: immunoregulatory effects and increasing the ability to kill the cells infected with virus.

Adjuvants, Immunologic↗
PubMed2004

[Signal transduction in the differentiation of human peripheral blood mononucleocytes towards dendritic cells induced by calcium ionophore].

AIM: To explore the intracellular signal transduction pathway in the differentiation of human peripheral blood mononucleocytes (PBMCs) towards dendritic cells (DCs) induced by calcium ionophore (CI). METHODS: PBMCs isolated from a healthy donor were cultured with A23187 plus rhGM-CSF, 100 microg/L each. In some experiments, PBMCs were cultured for 30 minutes with W-7 (10 micromol/L), CsA(0.5 mg/L) or KT5926(1 micromol/L) before addition of rhGM-CSF and A23187. After culture for 40 hours, morphological change of the cells were observed under phase contrast microscope; surface markers on treated PBMCs were analyzed by flow cytometry; the proliferation of allogeneic human T cells stimulated by the treated PBMCs was detected by MTT colorimetry. RESULTS: PBMCs of the healthy donor cocultured with rhGM-CSF plus CI for 40 hours had the typical morphology of DCs, with decreased CD14 expression, and increased CD83, CD80 and CD86 expressions. The proliferation of allogeneic T cells stimulated by PBMCs treated with A23187 plus rhGM-CSF was strengthened. But the morphological changes, surface marker expressions and the ability to enhancing proliferation of allogeneic T cells were inhibited to different degrees by W-7, CsA or KT5926. CONCLUSION: The differentiation of PBMCs towards DCs by CI may be modulated by Ca (2+)/calmodulin and multiple signal transduction pathways downstream.

Antigens, CD↗
PubMed2005

[Study on intrauterine infection of hepatitis B virus in pregnant women with hepatitis B surface antigen and hepatitis B e antigen negative].

OBJECTIVE: To explore the significance of intrauterine infection of hepatitis B virus in pregnant women with hepatitis B surface antigen (HBsAg) and hepatitis B e antigen (HBeAg) negative by nested polymerase chain reaction (PCR). METHODS: Twenty-four pregnant women with HBsAg and HBeAg negative but other HBV markers positive together with their infants were included as study group. Sixteen pregnant women with HBV marker negative and their infants were in the control group. HBV DNA in sera and peripheral blood mononuclear cells (PBMCs) of two groups was detected by nested PCR respectively. RESULTS: (1) In the study group, the positive rates of HBV DNA of pregnant women were 33% (8/24) in the sera and 42% (10/24) in PBMCs. Three women were detected HBV DNA in both serum and PBMCs. The rate of HBV infection was 63% (15/24); (2) also in the study group, the positive rates of HBV DNA of the infants were 13% (3/24) in the sera and 25% (6/24) in PBMCs. One newborn was detected HBV DNA in both serum and PBMCs, the rate of intrauterine infection of HBV was 33% (8/24); (3) HBV DNA was detected in sera and/or in PBMCs from four newborns of pregnant women with HBV DNA positive only in PBMCs, the positive ratio was 4/7. CONCLUSIONS: HBV intrauterine infection is possible in pregnant women with HBsAg and HBeAg negative. Detecting HBV-DNA in sera and PBMCs of pregnant women and their newborns by PCR is important clinical significance.

Adult↗
PubMed1995

Soluble CD14 promotes LPS activation of CD14-deficient PNH monocytes and endothelial cells.

Bacterial lipopolysaccharide (LPS) initiates the cascade of inflammatory events that, in infected patients, often result in a lethal systemic inflammatory response known as the sepsis syndrome. We studied LPS-stimulated expression of tissue factor (TF) in human peripheral blood mononuclear cells (PBMCs) and cultured endothelial cells or tumor necrosis factor-alpha (TNF-alpha) in PBMCs. CD14, a PBMC membrane protein, is involved in LPS signaling and is also present as a soluble molecule in serum. CD14 is absent from endothelial cells and, in varying degrees, from monocytes of patients with paroxysmal nocturnal hemoglobinuria (PNH). LPS stimulation of TF in normal monocytes was enhanced > 30-fold by serum at low concentrations of LPS (< or = 10 ng/ml). The serum dependence of endothelial cells was even more pronounced; a full response to LPS was not observed in endothelium under serum-free conditions, even with LPS concentrations as high as 100 ng/ml. To better define the role of CD14, CD14-deficient PBMCs from two patients with PNH were compared with normal PBMCs. Although less than 3% of PNH monocytes expressed CD14, LPS-induced synthesis of TF and TNF-alpha by PBMCs from PNH patients was inhibited by anti-CD14 antibodies. Because patient serum samples were found to contain soluble CD14, we sought to determine whether PNH monocytes might respond to LPS through an activation pathway dependent on soluble CD14. Recombinant soluble CD14 substituted for serum to enable LPS stimulation of endothelium, PNH PBMCs, and surprisingly, CD14-replete normal PBMCs. In addition, a truncated sCD14 containing the N-terminal 152 amino acids similarly enabled LPS stimulation of normal PBMCs. These data underscore the importance of soluble CD14 and suggest that CD14 present in serum enables LPS responses in PNH monocytes and endothelial cells and may even influence the effects of LPS in normal human phagocytes.

Antigens, CD↗
PubMed2001

Evidence of dysregulated cytokine production by sinus lavage and peripheral blood mononuclear cells in patients with treatment-resistant chronic rhinosinusitis.

BACKGROUND: Treatment-resistant chronic rhinosinusitis (CRS) imposes a clinical challenge. Its pathogenesis may be associated with dysregulated immune/inflammatory responses in the sinus. OBJECTIVE: To evaluate production of types 1 and 2 T cytokines (interferon gamma [IFN-gamma] and interleukin [IL] 5/IL-4, respectively) and regulatory/inflammatory cytokines (IL-10, IL-12, and IL-18) by sinus lavage (SL) cells and peripheral blood mononuclear cells (PBMCs) in patients with treatment-resistant CRS. METHODS: Sample SL cells and PBMCs obtained from 19 patients with treatment-resistant CRS were cultured with or without stimuli, and cytokine levels in the supernatant were measured using enzyme-linked immunosorbent assay. Control PBMC samples were obtained from 26 children. RESULTS: Chronic otitis media was found in 15 patients. Neutrophils and/or epithelial cells were dominant in SL cells. IFN-gamma, IL-12p40, and IL-10 (>100 pg/mL) were detected in SL cell cultures from 12, 9, and 8 patients, respectively. Production of IL-12p40 and IL-18 by SL cells correlated positively with phytohemagglutinin and IL-12p70 stimuli. In 12 patients, we detected IL-18 (>100 pg/mL) in SL cell cultures without stimuli, whereas PBMCs produced little IL-18, irrespective of stimuli. There was no correlation between cytokine levels produced by SL cells and PBMCs, except for IL-12p40 produced using IL-18. Decreased IFN-gamma production by PBMCs was observed in 6 patients with CRS compared with controls, but 4 of them had elevated IFN-gamma production by SL cells. Production of IL-12p40 by PBMCs was higher in 10 patients with CRS than in controls, and 7 of these patients had lower IL-10 production, resulting in an increased IL-12p40/IL-10 ratio. CONCLUSIONS: There is a role for locally produced regulatory cytokines in IFN-gamma production in the sinus in patients with treatment-resistant CRS. However, aberrant cytokine production patterns by PBMCs can be detected at high frequency in these patients, indicating that this can be used as a prognostic marker for patients with CRS.

Adolescent↗
PubMed1999

Cisplatin-based polychemotherapy reduces the natural cytotoxicity of peripheral blood mononuclear cells in patients with advanced ovarian carcinoma and their in vitro responsiveness to interleukin-12 incubation.

BACKGROUND: The aim of the current study was to evaluate the in vitro effect of IL-12 on the natural cytotoxicity of peripheral blood mononuclear cells (PBMCs) obtained from patients who underwent adjuvant-based cisplatin polychemotherapy for advanced ovarian carcinoma. The authors also investigated amifostine, a cytoprotective agent that appears to protect against chemotherapy damage to healthy tissues, to determine its effects on natural immune function. METHODS: Twenty-one women with advanced ovarian serous cystoadenocarcinoma who underwent adjuvant cisplatin-based polychemotherapy were included in the study, and 20 normal volunteer women matched for age served as controls. Six of the 21 women who underwent polychemotherapy received 1:3 amifostine pretreatment. Blood samples were obtained immediately before the first cycle of cisplatin-based polychemotherapy and within 24 hours after the completion of polychemotherapy infusion to evaluate the natural cytotoxic activity of PBMCs against the K562 cell line and the in vitro responsiveness of cytotoxic cells to interleukin-12 (IL-12). RESULTS: The in vivo administration of cisplatin-based polychemotherapy significantly reduced the natural killer cytotoxicity of PBMCs toward undetectable levels (2.2+/-3.1 vs. 9.2+/-7.0 lytic units, respectively, after and before cisplatin; P < 0.01), and the in vitro exposure to IL-12 did not increase the cytolytic activity of PBMCs (1.9+/-2.1 lytic units). PBMCs from the 6 patients who received random amifostine pretreatment were shown to have retained natural killer cytotoxicity after in vivo administration of cisplatin polychemotherapy (9.7+/-6.7 vs. 9.6+/-6.0 lytic units, respectively, after and before cisplatin; P = 0.9), and the incubation with IL-12 increased cytotoxic activity (13.4+/-6.9 lytic units) toward the levels observed in PBMCs of controls (14.0+/-4.6 lytic units). CONCLUSIONS: These data suggest that cisplatin-based polychemotherapy reduces the natural cytotoxicity of PBMCs in patients with advanced ovarian carcinoma as well as their in vitro responsiveness to IL-12 incubation. Amifostine demonstrated a protective effect on natural killer cell cytotoxicity and responsiveness to IL-12 in this small cohort of patients.

Amifostine↗
PubMed2001

TT virus (TTV) loads associated with different peripheral blood cell types and evidence for TTV replication in activated mononuclear cells.

TT virus (TTV) loads associated with the peripheral blood cells of seven patients known to carry the virus in plasma were investigated by real-time PCR. Whereas red cells/platelets were uniformly negative, six and four patients yielded positive peripheral blood mononuclear cells (PBMCs) and polymorphonuclear leukocytes, respectively, but viral titres were generally low. Fractionation of PBMCs into monocyte- and B, T4, and T8 lymphocyte-enriched subpopulations showed no pattern in the viral loads that might suggest the preferential association of TTV to one or more specific cell types. TTV-negative PBMCs absorbed measurable amounts of virus when incubated with infected plasma at 4 degrees C. Furthermore, cultures of TTV-negative phytohaemagglutinin-stimulated PBMCs exposed in vitro to virus-positive plasma and faecal extracts released considerable levels of infectious TTV into the supernatant fluid and the same was true for TTV-positive stimulated PBMCs. These results indicate that, whereas freshly harvested resting PBMCs seem to produce little, if any TTV, stimulated PBMCs actively replicate the virus.

Adult↗
PubMed1996

Effects of cryopreservation on immune responses. X. Decrease in interleukin-12 production by frozen human peripheral blood mononuclear cells is mediated by the endogenously hypersecreted interleukin-10.

The contrasting effects of freezing and radiation on lipopolysaccharide (LPS)-induced interleukin (IL)-10 production by human peripheral blood mononuclear cells (PBMCs) have recently been reported. In view of the potent inhibitory properties of IL-10 on IL-12 secretion and the central role played by IL-12 in the immune system, the influences of freezing and radiation on LPS-induced IL-12 production by PBMCs were studied. Frozen PBMCs secreted significantly smaller amounts of IL-12 than fresh cells. In contrast, the in vitro-irradiated PBMCs produced significantly larger amounts of IL-12. Culture of frozen cells in the presence of exogenous anti-IL-10 antibody resulted in the production of significantly larger amounts of IL-12. These results suggest that the endogenously hyperscreted IL-10 is primarily responsible for the observed decrease in IL-12 released by the frozen cells. They further suggest that the increased amounts of IL-12 secreted by the irradiated PBMCs could account for the previously reported increase in IL-2 and interferon (IFN)-gamma release by the irradiated PBMCs and the radiation-induced immunopotentiation and tumor regression. Considering the pivotal role played by IL-12 in the immune system, and in antimicrobial and antitumor activities, production of only 10% of the normal levels by the frozen cells could have profound impact on patients receiving such frozen PBMCs as stem cell support following myeloablative therapy. Administration of exogenous IL-12 at the time of frozen PBMC transplantations might have a therapeutic value in these patients.

Cells, Cultured↗
PubMed1999

Modulation of cytokine release from mononuclear cells by prostacyclin, IL-4 and IL-13.

In a previous study, we reported that cicaprost, a stable prostacyclin analogue can inhibit the release of granulocyte-macrophage colony-stimulating factor (GM-CSF) from activated human peripheral mononuclear blood cells (PBMCs). Since interleukin (IL-4) and IL-13 have been shown to inhibit the release of cytokines from PBMCs we tested the hypothesis that prostacyclin in combination with IL-4 or IL-13 can act synergistically to modulate the release of IL-10, generally associated with anti-inflammatory properties, and the pro-inflammatory cytokine tumour necrosis factor alpha (TNF-alpha). For this purpose, PBMCs were isolated over Ficoll, stimulated with lipopolysaccharide (LPS) and incubated in the presence of cicaprost, IL-4 or IL-13. There was a significant reduction in TNF-alpha as well as IL-10 secretion from LPS-stimulated PBMCs following incubation with IL-4 or IL-13. In contrast, cicaprost reduced the secretion of TNF-alpha but led to a slight enhancement of IL-10 release from PBMCs. When LPS-activated PBMCs were incubated in the presence of cicaprost and IL-4 or IL-13 there was a selective, synergistic inhibition of the TNF-alpha release which was not observed for IL-10. Thus, our data suggest that prostacyclin can synergize with cytokines to selectively inhibit the release of pro-inflammatory cytokines from PBMCs.

Cell Survival↗
PubMed1996

Role of CD18-dependent and CD18-independent mechanisms in the increased leukocyte adhesiveness and in the variations of circulating white blood cell populations induced by anti-CD3 monoclonal antibodies.

Anti-CD3 antibodies induce a quick and profound depletion of peripheral blood mononuclear cells (PBMCs) that is not well understood. We studied the effect of OKT3, a mouse monoclonal antibody against the human CD3 complex, on the in vitro adhesion of human PBMCs to monolayers of fresh and fixed human umbilical vein endothelial cells (HUVECs). OKT3 induced an increased adhesiveness of PBMCs. This phenomenon was blocked with anti-CD18 antibodies, indicating the participation of beta 2 integrins. As this increased adhesiveness could explain the lymphopenia by adhesion of PBMCs to endothelial cells and their sequestration in some peripheral vascular beds, we studied the effect of anti-CD18 antibodies in vivo on mice injected with 145/2C11, a hamster monoclonal antibody against murine CD3. Mice treated with 145/2C11 presented with a transient granulocytopenia and a sustained reduction in PBMCs. A monoclonal anti-CD18 antibody prevented the granulocytopenia but had no effect on the drop in PBMCs. Consequently, the in vivo depletion of PBMCs after administration of an anti-CD3 monoclonal antibody involves CD18-independent mechanisms, while the transient drop in polymorphonuclear cells appears to be CD18-dependent.

Adult↗
PubMed1998

Relations between surface expression of the interleukin-2 receptor and release of the soluble form of the receptor in cultured mononuclear cells from patients with rheumatoid arthritis or systemic lupus erythematosus.

The relationship between surface expression of the interleukin-2 receptor (IL-2R) and release of the soluble form of the receptor (sIL-2Ralpha or sCD25) was investigated with peripheral blood mononuclear cells (PBMCs) from individuals with rheumatoid arthritis (RA) or systemic lupus erythematosus (SLE). The spontaneous release of sCD25 was significantly increased in PBMCs from RA patients and decreased in cells from SLE patients, compared with normal controls. However, the extent of sCD25 release from phytohaemagglutinin (PHA)-stimulated PBMCs did not differ between RA or SLE patients and normal controls. The serum concentration of sCD25 was significantly increased in SLE or RA patients compared with the normal controls. Whereas the surface expression of CD25 by unstimulated PBMCs did not differ among the three groups of subjects, this parameter was significantly reduced for PHA-stimulated PBMCs from RA patients relative to those from normal controls. The surface expression of CD25 showed a positive correlation with sCD25 release for PBMCs from SLE patients under either basal or stimulated conditions. No such relation was apparent for cells from RA patients. The surface expression of IL-2Rbeta (CD 122) under basal or stimulated conditions was significantly reduced in PBMCs from RA or SLE patients, compared with cells from normal controls. Thus, the increased concentration of sCD25 in the serum of individuals with these autoimmune rheumatic diseases may result from two different mechanisms: an increase in the spontaneous release of sCD25 in RA, and reduced clearance of this protein in SLE.

Adult↗