Human Peripheral Mononuclear Blood Research Articles

Combined effect of methotrexate and bifidobacteria metabolites on TNFα AND IFNγ production by human peripheral blood mononuclears

Methotrexate (Mtx) is a first-line drug for the treatment of numerous rheumatic and non-rheumatic disorders, including oncological disdiseases. However, therapeutic efficacy of Mtx is limited by severe toxicity to many organs (myelo-, hepato-, nephrotoxicity, mucositis, enteritis, dysbiosis at various human biotopes, etc.). Recently, a number of studies showed that some metabolites of Bifidobacteria and Lactobacilli are able to enhance effect of chemotherapeutic drugs and limit their toxic properties. The aim of the present work was to study the possible potentiating action of Bifidobacteria cell-free supernatants and methotrexate upon secretion of pro-inflammatory TNF and IFN cytokines by human peripheral blood mononuclear cells (PBMCs). The immunoregulatory effects upon production of TNF and IFNg was evaluated in the in vitro model of cultured PBMC supplemented with Bifidobacteria metabolites, methotrexate, or their combination. Analysis of the combined effect of Bifidobacteria metabolites and Mtx on the cytokine production revealed their synergism towards the key pro-inflammatory cytokines (TNF and IFN). We found an increase against the control cultures (with Mtx only), inhibition of the early pro-inflammatory cytokine TNF production. On the contrary, we revealed an increased secretion of IFN which regulates the effector cells. The results obtained with these cytokines suggest the presence of a potentiating effect of Bifidobacteria metabolites upon anti-inflammatory and immunoregulatory properties of methotrexate. Thus, Bifidobacteria metabolites can be considered a promising agent which potentiates the therapeutic action of methotrexate by suppressing TNF secretion and stimulating IFN by immunocompetent cells. Further studies of the combined effects of Mtx and metabolites from the intestinal microbiota upon the cytokine production by effector cells could be recommended, aiming to enhance therapeutic effect of methotrexate and limit its toxic properties using the Bifidobacteria metabolites.

In Vitro and In Vivo Relevant Antineoplastic Activity of Platinum(II) Complexes toward Triple-Negative MDA-MB-231 Breast Cancer Cell Line.

Two platinum complexes [Pt(HL3)Cl]·H2O (3) and [Pt(HL4)Cl]·H2O (4) containing α- and β-naphthyl groups, respectively, were investigated in more detail in vitro and in vivo for antineoplastic activity. The cytotoxicity activity induced by these platinum(II) compounds against breast cancer (MDA-MB-231 and MCF-7), lung (A549), prostate (PC3), pancreas (BXPC-3), and normal peripheral blood mononuclear (PBMC) cells were evaluated by MTT assay. The cell viability MTT assay showed that complex (4) was more cytotoxic to all cancer cell lines tested and less cytotoxic against human PBMC. Therefore, complex (4) was selected to further investigate the mechanism of cytotoxic effects involved against MDA-MB-231 cell line (human triple-negative breast cancer). Sub-G1 analysis of the cell cycle showed that this complex induces cell death by apoptosis due to the cell loss of DNA content detected in flow cytometry. The cytotoxic effect induced by complex (4) was associated with the capability of the complex to induce mitochondrial membrane depolarization, as well as increase ROS levels and caspase activation, as a result of the activation of both extrinsic and intrinsic apoptosis pathways. Ultrastructural alterations were observed using scanning and transmission electron microscopy (SEM and TEM), such as membrane blebbing, filopodia reduction, empty mitochondrial matrix, and DNA fragmentation. Furthermore, complex (4) was tested in an MDA-MB-231 tumor nodule xenograft murine model and demonstrated a remarkable reduction in tumor size in BALB/c nude mice, when compared to the control animals.

Abstract 1977: Extending the capabilities of a high-parameter immunophenotyping assay with cytoplasmic staining applications for mass cytometry

Abstract Mass cytometry, empowered by CyTOF® technology, utilizes monoisotopic metal-tagged antibodies and a high-sensitivity mass cytometer to allow high-dimensional single-cell analysis in complex biological samples. The 30-marker panel Maxpar® Direct™ Immune Profiling Assay™ (Cat. No. 201325) for suspension mass cytometry provides an unprecedented sample-to-answer solution for detecting and analyzing 30 surface markers in a single experiment. With 18 open mass channels for additional biological markers, the Maxpar Direct Assay facilitates panel expansion and enables flexibility for higher multiplexity and applications. Among the potential complementary applications with the Maxpar Direct Assay, intracellular cytokine staining (ICS) is of particular interest as it may be used to assess infiltrating immune cell phenotypes in the tumor microenvironment. However, for the purpose of assessing cell viability in this workflow, the effectiveness of the Cell-ID™ Intercalator-Rh (Cat. No. 201103) that is included in the Maxpar Direct Assay is in question, since cell permeabilization during ICS can potentially damage the DNA-intercalator bondIn this study, we investigated the compatibility of the Cell-ID Intercalator-Rh (103Rh) with intracellular staining. To do this, we stained either human peripheral blood mononuclear cell (PBMC) or whole blood samples (FLDM-400287) with the Maxpar Direct Assay followed by intracellular staining for the detection of expressed cytokines. The intercalator was evaluated for its ability to discriminate live and dead cells when the sample undergoes surface antibody staining. The monoisotopic Cell-ID Cisplatin-194Pt (Cat. No. 201194) was used as the control to provide benchmark measurement of cell viability of the samples. For both sample types, known percentages of heat-killed PBMC were spiked into the samples in order to evaluate the influence of dead cells. We demonstrate that 103Rh provides equivalent functionality as a cell viability indicator during intracellular staining for cytoplasmic proteins compared to Cell-ID Cisplatin-194Pt. This work was designed to support the use of the Maxpar Direct Immune Profiling Assay in combination with additional intracellular markers. Overall, these findings expand the applicability of Cell-ID Intercalator-Rh (103Rh) to processes that involve cytoplasmic staining. For Research Use Only. Not for use in diagnostic procedures. Citation Format: Noah Saederup, Huihui Yao, Michael Cohen, Leslie Fung. Extending the capabilities of a high-parameter immunophenotyping assay with cytoplasmic staining applications for mass cytometry [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 1977.

Antibody validation for Western blot: By the user, for the user

Antibody validation for Western blot: By the user, for the user

Effects of Light on In Vitro Production of Melatonin by Human Peripheral Blood Mononuclear, Polymorphonuclear, and Whole Blood Cells

Recent studies have shown that melatonin can be secreted, in addition to other sources, by peripheral blood mononuclear cells (PBMCs). We investigated whether melatonin could also be secreted by cultured polymorphonuclear (PMNs) and whole blood (WB) cells under resting and stimulated conditions. In addition, influences of the intensity and color of light on the production of melatonin by these cells were estimated. Blood samples were collected from a healthy volunteer, and PBMCs and PMNs were isolated. The PBMC, PMN, and WB cultures were exposed for 8 h to light intensities of 0, 20, 50, 100, 300, and 500 lux and to white, red, blue, and green lights in the presence/absence of mitogens. Levels of melatonin in supernatants were detected by enzyme-linked immunosorbent assay (ELISA). In addition to PBMCs, PMNs and WB cells were found to also produce melatonin, and this production was increased due to mitogen activations. The most effective intensity of light, which suppresses melatonin secretion, was 100 lux. There were no significant differences between the influences of different monochromatic lights on the melatonin production by the examined blood cell cultures. Thus, PBMCs, PMNs, and WB cultures can produce melatonin, and mitogen activation causes a higher production of this hormone. Moreover, although white light suppressed melatonin secretion at 100 lux, there was no difference among various types of lights. © 2019, Springer Science+Business Media, LLC, part of Springer Nature.

Enrichment of extracellular DNA from the cultivation medium of human peripheral blood mononuclears with genomic CpG rich fragments results in increased cell production of IL-6 and TNF-a via activation of the NF-kB signaling pathway

Previously, it was found that blood plasma extracellular DNA (ecDNA) of patients with rheumatoid arthritis (RA) is enriched with CpG-rich genomic DNA fragments, which contain TLR9 ligands (Veiko et al., 2006). In this study we have demonstrated that ecDNA of a RA patient and model fragments added to a cultivation medium of peripheral blood mononuclear cells (PBMC) of healthy donors stimulate expression of genes for the TLR9-MyD88-NF-kB signaling pathway; this leads to a significant increase in concentrations of the proinflammatory cytokines IL-6 and TNF-a in the cultivation medium. Human genomic DNA non-enriched with the CpG sequences did not stimulate IL-6 and TNF-a synthesis in PBMC. A scheme explaining the potential role ecDNA in the induction and maintenance of increased levels of the proinflammatory cytokines under conditions damaging the human cells has been proposed.

Erichment of extracellular DNA from the cultivation medium of human peripheral blood mononuclears with Genomic CpG rich fragments results in increased cell production of IL-6 and TNFα via activation of the NF-κB signaling pathway

Erichment of extracellular DNA from the cultivation medium of human peripheral blood mononuclears with Genomic CpG rich fragments results in increased cell production of IL-6 and TNFα via activation of the NF-κB signaling pathway

Butachlor induced dissipation of mitochondrial membrane potential, oxidative DNA damage and necrosis in human peripheral blood mononuclear cells

Butachlor is a systemic herbicide widely applied on rice, tea, wheat, beans and other crops; however, it concurrently exerts toxic effects on beneficial organisms like earthworms, aquatic invertebrates and other non-target animals including humans. Owing to the associated risk to humans, this chloroacetanilide class of herbicide was investigated with the aim to assess its potential for the (i) interaction with DNA, (ii) mitochondria membrane damage and DNA strand breaks and (iii) cell cycle arrest and necrosis in butachlor treated human peripheral blood mononuclear (PBMN) cells. Fluorescence quenching data revealed the binding constant (Ka=1.2×104M−1) and binding capacity (n=1.02) of butachlor with ctDNA. The oxidative potential of butachlor was ascertained based on its capacity of inducing reactive oxygen species (ROS) and substantial amounts of promutagenic 8-oxo-7,8-dihydro-2′-deoxyguanosine (8-oxodG) adducts in DNA. Also, the discernible butachlor dose-dependent reduction in fluorescence intensity of a cationic dye rhodamine (Rh-123) and increased fluorescence intensity of 2′,7′-dichlorodihydro fluorescein diacetate (DCFH-DA) in treated cells signifies decreased mitochondrial membrane potential (ΔΨm) due to intracellular ROS generation. The comet data revealed significantly greater Olive tail moment (OTM) values in butachlor treated PBMN cells vs untreated and DMSO controls. Treatment of cultured PBMN cells for 24h resulted in significantly increased number of binucleated micronucleated (BNMN) cells with a dose dependent reduction in the nuclear division index (NDI). The flow cytometry analysis of annexin V−/7-AAD+ stained cells demonstrated substantial reduction in live population due to complete loss of cell membrane integrity. Overall the data suggested the formation of butachlor–DNA complex, as an initiating event in butachlor-induced DNA damage. The results elucidated the oxidative role of butachlor in intracellular ROS production, and consequent mitochondrial dysfunction, oxidative DNA damage, and chromosomal breakage, which eventually triggers necrosis in human PBMN cells.

781 IDENTIFICATION OF HEPATITIS C VIRUS (HCV) GLYCOPROTEIN E2 DOMAINS AND RESIDUES RESPONSIBLE FOR INTERACTION WITH HEPARAN SULFATE

780 UPTAKE OF HCV NON-ENVELOPED PARTICLES FROM HUMAN PERIPHERAL BLOOD MONONUCLEAR CELLS (PBMCS) LEADS TO MODULATION OF THE IMMUNE RESPONSE P.P. Doumba, E. Serti, M. Boutsikou, M.M. Konstandoulakis, U. Georgopoulou, J. Koskinas. 2nd Department of Internal Medicine, Hippokration Hospital, Laboratory of Surgical Research, 1st Department of Propaedeutic Surgery, Hippokration Hospital, Medical School, University of Athens, Molecular Virology Laboratory, Hellenic Pasteur Institute, Athens, Greece E-mail: jdoumba@yahoo.gr

In vitro activity of hypnophilin from Lentinus strigosus: a potential prototype for Chagas disease and leishmaniasis chemotherapy

Hypnophilin and panepoxydone, terpenoids isolated from Lentinus strigosus, have significant inhibitory activity on Trypanosoma cruzi trypanothione reductase (TR). Although they have similar TR inhibitory activity at 10 μg/mL (40.3 μM and 47.6 μM for hypnophilin and panepoxydone, respectively; ~100%), hypnophilin has a slightly greater inhibitory activity (~71%) on T. cruzi amastigote (AMA) growth in vitro as well as on in vitro phytohemagglutinin (PHA)-induced peripheral blood mononuclear (PBMC) proliferation (~70%) compared to panepoxydone (69% AMA inhibition and 91% PBMC inhibition). Hypnophilin and panepoxydone at 1.25 μg/mL had 67% inhibitory activity onLeishmania (Leishmania) amazonensis amastigote-like (AMA-like) growth in vitro. The panepoxydone activity was accompanied by a significant inhibitory effect on PHA-induced PBMC proliferation, suggesting a cytotoxic action. Moreover, incubation of human PBMC with panepoxydone reduced the percentage of CD16(+) and CD14(+) cells and down-regulated CD19(+), CD4(+) and CD8(+) cells, while hypnophilin did not alter any of the phenotypes analyzed. These data indicate that hypnophilin may be considered to be a prototype for the design of drugs for the chemotherapy of diseases caused by Trypanosomatidae.

Simultaneous Quantification of Intracellular Natural and Antiretroviral Nucleosides and Nucleotides by Liquid Chromatography−Tandem Mass Spectrometry

Nucleoside reverse transcriptase inhibitors (NRTI) require intracellular phosphorylation, which involves multiple enzymatic steps to inhibit the human immunodeficiency virus type 1 (HIV-1). NRTI-triphosphates (NRTI-TP) compete with endogenous 2'-deoxyribonucleosides-5'-triphosphates (dNTP) for incorporation by the HIV-1 reverse transcriptase (RT). Thus, a highly sensitive analytical methodology capable of quantifying at the low femtomoles/10(6) cells level was necessary to understand the intracellular metabolism and antiviral activity of NRTIs in human peripheral blood mononuclear (PBM) cells and in macrophages. A novel, rapid, and a reproducible ion-pair chromatography-tandem mass spectrometry (MS/MS) method was developed to simultaneously quantify the intracellular phosphorylated metabolites of abacavir, emtricitabine, tenofovir disoproxil fumarate, amdoxovir, and zidovudine, as well as four natural endogenous dNTP. Positive or negative electrospray ionization was chosen with specific MS/MS transitions for improved selectivity on all the compounds studied. The sample preparation, the ion-pair reagent concentration, and buffer composition were optimized, resulting in the simultaneous quantification of 13 different nucleotides in a total run time of 30 min. This novel method demonstrated optimal sensitivity (limit of detection 1-10 nM for various analytes), specificity, and reproducibility to successfully measure NRTI-TP and dNTP in human PBM cells and macrophages.

Analysis of toll-like receptor-dependent production of proinflammatory cytokines in vitro by human peripheral blood mononuclears of donors and patients with primary immunodeficiency

The production of TNF-alpha and IFN-alpha cytokines by peripheral blood mononuclears in response to stimulation by TLR2/6, TLR4, TLR5, TLR9 ligands (zymosan, LPS, flagellin, and CpG-oligodeoxynucleotide, respectively) was studied in donors and patients with common variable immunodeficiency. Individual characteristics of TNF-alpha production by mononuclears were revealed in donors. Reduced stimulated production of TNF-alpha in response to stimulation with TLR4 and TLR5 ligands in vitro was detected in patients with common variable immunodeficiency.

Antiviral and Cellular Metabolism Interactions between Dexelvucitabine and Lamivudine

Studies on cellular drug interactions with antiretroviral agents prior to clinical trials are critical to detect possible drug interactions. Herein, we demonstrated that two 2'-deoxycytidine antiretroviral agents, dexelvucitabine (known as beta-d-2',3'-didehydro-2',3'-dideoxy-5-fluorocytidine, DFC, d-d4FC, or RVT) and lamivudine (3TC), combined in primary human peripheral blood mononuclear (PBM) cells infected with human immunodeficiency virus 1 strain LAI (HIV-1(LAI)), resulted in additive-to-synergistic effects. The cellular metabolism of DFC and 3TC was studied in human T-cell lymphoma (CEM) and in primary human PBM cells to determine whether this combination caused any reduction in active nucleoside triphosphate (NTP) levels, which could decrease with their antiviral potency. Competition studies were conducted by coincubation of either radiolabeled DFC with different concentrations of 3TC or radiolabeled 3TC with different concentrations of DFC. Coincubation of radiolabeled 3TC with DFC at concentrations up to 33.3 microM did not cause any marked reduction in 3TC-triphosphate (TP) or any 3TC metabolites. However, a reduction in the level of DFC metabolites was noted at high concentrations of 3TC with radiolabeled DFC. DFC-TP levels in CEM and primary human PBM cells decreased by 88% and 94%, respectively, when high concentrations of 3TC (33.3 and 100 microM) were added, which may influence the effectiveness of DFC-5'-TP on the HIV-1 polymerase. The NTP levels remained well above the median (50%) inhibitory concentration for HIV-1 reverse transcriptase. These results suggest that both beta-d- and beta-l-2'-deoxycytidine analogs, DFC and 3TC, respectively, substrates of 2'-deoxycytidine kinase, could be used in a combined therapeutic modality. However, it may be necessary to decrease the dose of 3TC for this combination to prove effective.

CyclinA2 as a Proliferation Marker for Peripheral Blood T Cell Subsets Measured by Flow Cytometry.

Proliferation is regarded as a sensitive parameter for assessing immune response to infectious agents, autoimmune conditions, and organ engraftment in transplantation. Proliferation of peripheral blood mononuclear (PBMC) cells has been measured by a number of flow cytometric methods including propidium iodide (PI), incorporation of Bromo-deoxy-uridine (BrdUr), and dilution of Carboxy-fluorescein diacetate, succinimidyl ester (CFSE) intensity. Standardization of these methods however, has been hampered by their technical complexity. The restricted expression of CyclinA2 protein in the cytoplasm during the S and G2 cell cycle phases has provided the basis for a simplified intracellular flow-based proliferation assay. In these studies, ex vivo stimulated human PBMC were tested for the validation of CyclinA2 as a proliferation marker for T cell subsets. Freshly isolated or cryopreserved PBMCs were incubated in vitro with SEB/CD28 for periods up to 72 hours and processed using different methodologies for lymphocyte cell cycle measurement. These included BrdUr /7AAD, PI/CyclinA2; cylinA2 with additional T cell phenotyping markers and a combined CyclinA2 /BrdUr proliferation method. Results for each cell subset were scored for the percentage of positive proliferating cells by each methodology. PBMC co-stained for CyclinA2 and DNA content by PI demonstrated that all cells expressing Cyclin A2 corresponded to cells at S or G2 phase. Furthermore, the time course assays combining BrdUr labeling with CvclinA2 confirmed that CyclinA2 expression corresponded selectively to cells incorporating BrdUr. When PMBC were surface phenotyped for CD3 and CD4/CD8, reproducible populations of CD4 and CD8 T cell subsets incorporating BrdUr were measured for expression of Cyclin A2. In our assay model 11 to 15 % positively stained for Cyclin A2 corresponded to approximately 10% and 5% of CD3/8 and CD3/4 CyclinA2 cells, respectively. The percentage of total BrdUr and total CyclinA2 positive cells that were detected in the dual-labeled specimens corresponded to the percentage detected by each individual method. In conclusion, measurement of in vitro lymphocytes proliferation using expression of CyclinA2 protein expression is highly correlated with BrdUr uptake demonstrating that CyclinA2 is an accurate marker of cell proliferation. Preparation of cells for measuring Cyclin A2 takes only 60 minutes as compared with a total 12 to 16 hours for BrdUr pulsing and staining time. The simple CyclinA2 preparation method described here makes it a practical, fast, and reliable proliferation flow assay that can be easily standardized for enumeration of proliferating lymphocyte subsets.

Pharmacology and Pharmacokinetics of the Antiviral Agent β-d-2′,3′-Dideoxy-3′-Oxa-5-Fluorocytidine in Cells and Rhesus Monkeys

Beta-D-2',3'-dideoxy-3'-oxa-5-fluorocytidine (D-FDOC) is an effective inhibitor of human immunodeficiency virus 1 (HIV-1) and HIV-2, simian immunodeficiency virus, and hepatitis B virus (HBV) in vitro. The purpose of this study was to evaluate the intracellular metabolism of d-FDOC in human hepatoma (HepG2), human T-cell lymphoma (CEM), and primary human peripheral blood mononuclear (PBM) cells by using tritiated compound. By 24 h, the levels of D-FDOC-triphosphate (D-FDOC-TP) were 2.8 +/- 0.4, 6.7 +/- 2.3, and 2.0 +/- 0.1 pmol/10(6) cells in HepG2, CEM, and primary human PBM cells, respectively. Intracellular D-FDOC-TP concentrations remained greater than the 50% inhibitory concentration for HIV-1 reverse transcriptase for up to 24 h after removal of the drug from cell cultures. In addition to d-FDOC-monophosphate (D-FDOC-MP), -diphosphate (D-FDOC-DP), and -TP, D-FDOC-DP-ethanolamine and d-FDOC-DP-choline were detected in all cell extracts as major intracellular metabolites. D-FDOC was not a substrate for Escherichia coli thymidine phosphorylase. No toxicity was observed in mice given D-FDOC intraperitoneally for 6 days up to a dose of 100 mg/kg per day. Pharmacokinetic studies in rhesus monkeys indicated that D-FDOC has a t(1/2) of 2.1 h in plasma and an oral bioavailability of 38%. The nucleoside was excreted unchanged primary in the urine, and no metabolites were detected in plasma or urine. These results suggest that further safety and pharmacological studies are warranted to assess the potential of this nucleoside for the treatment of HIV- and HBV-infected individuals.

Synthesis, anti-HIV activity, and molecular mechanism of drug resistance of L-2',3'-didehydro-2',3'-dideoxy-2'-fluoro-4'-thionucleosides.

beta-l-2',3'-Didehydro-2',3'-dideoxy-2'-fluoro-4'-thionucleosides (beta-l-2'-F-4'-S-d4Ns) have been synthesized and evaluated against HIV-1 in primary human lymphocytes. The key intermediate 8, which was prepared from 2,3-O-isopropylidene-l-glyceraldehyde 1 in 13 steps, was condensed with various pyrimidine and purine bases followed by elimination and deprotection to give the target compounds, beta-l-2'-F-4'-S-d4Ns (17-20 and 27-30). The antiviral activity of the newly synthesized compounds was evaluated against HIV-1 in human peripheral blood mononuclear (PBM) cells, among which the cytosine 17, 5-fluorocytosine 18, and adenine 27 derivatives showed potent anti-HIV activities (EC(50) = 0.12, 0.15, and 1.74 microM, respectively) without significant cytotoxicity up to 100 microM in human PBM, CEM, and Vero cells. The cytosine derivative 17 (beta-l-2'-F-4'-S-d4C), however, showed cross-resistance to a 3TC-resistant variant (HIV-1(M184V)). Molecular modeling studies suggest that the pattern of antiviral activity, similar to that of beta-l-2'-F-d4N, stemmed from their conformational and structural similarities. The isosteric substitution of sulfur for 4'-oxygen was well tolerated in the catalytic site of HIV-1 reverse transcriptase in the wild-type virus. However, the steric hindrance between the sugar moiety of the unnatural l-nucleoside and the side chains of Val184 of M184V RT in 3TC-resistant mutant HIV strains destabilizes the RT-nucleoside triphosphate complex, which causes the cross-resistance to 3TC (M184V mutant).

Synthesis and anti-HIV and anti-HBV activities of 2'-fluoro-2', 3'-unsaturated L-nucleosides.

The synthesis of L-nucleoside analogues containing 2'-vinylic fluoride was accomplished by direct condensation method, and their anti-HIV and anti-HBV activities were evaluated in vitro. The key intermediate 8, the sugar moiety of our target compounds, was prepared from 1,2-O-isopropylidene-L-glyceraldehyde via (R)-2-fluorobutenolide intermediate 5 in five steps. Coupling of the acetate 8 with the appropriate heterocycles (silylated uracil, thymine, N4-benzoylcytosine, N4-benzoyl-5-fluorocytosine, 6-chloropurine, and 6-chloro-2-fluoropurine) in the presence of Lewis acid afforded a series of 2'-fluorinated L-nucleoside analogues (15-18, 23-26, 36-45). The newly synthesized compounds were evaluated for their antiviral activities against HIV-1 in human peripheral blood mononuclear (PBM) cells and HBV in 2.2.15 cells. Cytosine 23, 5-fluorocytosine 25, and adenine 36 derivatives exhibited moderate to potent anti-HIV (EC50 0.51, 0.17, and 1.5 microM, respectively) and anti-HBV (EC50 0.18, 0.225, and 1.7 microM, respectively) activities without significant cytotoxicity up to 100 microM in human PBM, Vero, CEM, and HepG2 cells.

Immunomodulatory effects of Bacillus firmus.

3-day-old miniature piglets were stimulated in vivo with Bacillus firmus by the intraperitoneal or intragastric route for 1 d. Cells containing IgA and IgG2 were detected in the ileum in all stimulated but not in control animals. The frequency of blood CD3+ cells increased after intraperitoneal administration of B. firmus, the ratio of polymorphonuclears to lymphocytes increased in all stimulated piglets. B. firmus induced antitumor immunity in rats with transplanted Yoshida sarcoma cells. Granular lymphocytes and dead tumor cells were found in peritoneal exudate of stimulated animals. B. firmus induced IFN-gamma synthesis in human blood lymphocytes stimulated in vitro for 1 d. The amount of TNF-alpha produced by these stimulated human peripheral blood mononuclears (PBMC) was lower than that of PBMC stimulated with some other bacterial immunomodulators. Cells containing TGF-beta or IL-8 were not found in human PBMC stimulated with B. firmus.

Effect of activation of Ca2+, Mg2+-dependent endonuclease on proliferative response of human peripheral blood lymphocytes

Activity of Ca2+, Mg2+-dependent endonuclease in human peripheral blood mononuclears is studied. Intact cells exhibit extremely low activity of the enzyme. Treatment with the synthetic hexapeptide imunofan considerably stimulates endonuclease activity in mononuclears. This activation does not depend on additional protein synthesis. An 1-h incubation in the presence of cycloheximide also activates Ca2+, Mg2+-dependent endonuclease. These data suggest that imunofant and/or cycloheximide activate the apoptotic cascade. This leads to activation of endonuclease, which is not synthesizedde novo but persists in the cell in the form of inactive precursor.

Effect of the dose of dexamethasone and cell population composition on thein Vitro production of tumor necrosis factor and interleukin-6 by human peripheral blood mononuclears

In vitro experiments demonstrate that various doses of dexamethasone not only inhibit production of interleukin-6 and tumor necrosis factor but also markedly stimulate it in cells of the total pool of human peripheral blood mononuclears. Production of tumor necrosis factor in the presence of dexamethasone is stimulated in all donors, while production of interleukin-6 is strongly inhibited, usually in a dose-dependent manner.