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PubMedDate not supplied

Combination of adoptive immunotherapy with Herceptin for patients with HER2-expressing breast cancer.

Clinical use of Herceptin (trastuzumab), which is a humanized monoclonal antibody against HER2, started for patients with HER2-overexpressing breast cancer. To potentiate the efficacy of the Herceptin therapy, this study focused on the combination of Herceptin with activated immune lymphocytes. We used peripheral blood mononuclear cells (PBMCs) as effector cells and used HER2-unexpressing K562 cells, HER2-weakly-expressing breast carcinoma cells (Breast-M), or HER2-strongly-expressing breast carcinoma cells (BT-474) as target cells. Interleukin-2 (IL-2)-activated PBMCs, IL-2/OKT-3-activated PBMCs and a streptococcal preparation OK-432-activated PBMCs were generated and used as effector cells. Cytotoxic activity was determined with 4-hour 51Cr release assay. Both fresh PBMCs and activated PBMCs exhibited Herceptin-dependent cytotoxicity. Importantly, Herceptin-dependent cytotoxicity was found even at a lower effector to target cell ratio (E/T ratio) than that of Herceptin-independent cytotoxicity. In addition, Herceptin-dependent cytotoxicity by these activated PBMCs was observed even in HER2-weakly-expressing Breast-M cells. Since gamma-globulin or anti-CD16 antibody abrogated Herceptin-dependent cytotoxicity, it seems likely that antibody-dependent cellular cytotoxicity (ADCC) plays an important role in the Herceptin-dependent cytotoxicity. We present a recurrent breast cancer patient with malignant pleural effusion, in which HER2-strongly-expressing tumor cells were present, who was undergoing Herceptin therapy. Cluster formation between tumor cells and intrapleural mononuclear cells was induced 24 hours after intravenous injection of Herceptin (4 mg/kg). Mononuclear cells bound specifically to HER2-strongly-expressing tumor cells but not to other cells, such as mesothelial cells, suggested a Herceptin-mediated binding like ADCC in vivo. Taken together, these findings suggest that the combination of Herceptin with various types of activated lymphocytes may be a new therapeutic strategy, not only for HER2-strongly-expressing breast cancer but also for HER2-weakly-expressing cancer.

Adenocarcinoma↗
PubMed2004

Effect of IL-18 on peripheral blood mononuclear cells of chronic hepatitis B and hepatitis B virus DNA released by HepG2.2.15 cell lines.

BACKGROUND: Interleukin-18 (IL-18), a pro-inflammatory cytokine that induces interferon-gamma (IFN-gamma) production in T cells and natural killer cells, plays a critical role in the T-lymphocyte helper type 1 (Th1) response. This study was designed to explore the effect of IL-18 on peripheral blood mononuclear cells (PBMCs) derived from chronic hepatitis B (CHB) and on hepatitis B virus (HBV) DNA released by HepG2.2.15 cell lines, which were transfected with hepatitis B virus gene in vitro. METHODS: PBMCs isolated from 25 healthy people and 25 patients with CHB were stimulated with HBcAg and IL-18 of various concentrations for 72 hours. The levels of IFN-gamma in the supernatants of cultured PBMCs were determined by ELISA. After the stimulation of IL-18 of various concentrations, PBMCs derived from one patient were co-cultured for 96 hours with HepG2.2.15 cells which had been cultured for 24 hours, and then the supernatants were collected by centrifugation and used for HBV DNA quantitative assay. RESULTS: When PBMCs were stimulated by HBcAg and IL-18 at various concentrations, the levels of IFN-gamma in the supernatants of CHB groups were much higher than those in normal control groups, at 0.2 ng/ml: t=11.70, P<0.01; at 1.0 ng/ml: t=16.19, P<0.01; and at 5.0 ng/ml: t=20.12, P<0.01. In the CHB groups, the levels of IFN-gamma in the supernatants of PBMCs stimulated by HBcAg alone were lower than both those stimulated by HBcAg and IL-18 at various concentrations and those stimulated by HBcAg and IL-18 (5.0 ng/ml) together with IL-12 (mild: t=2.20, P<0.05; moderate: t=2.97, P<0.05; severe: t=0.66, P>0.05). The content of HBV DNA in the supernatant of co-cultivation of HepG2.2.15 cells and PBMCs without stimulated materials was higher than that stimulated by HBcAg and IL-18 at various concentrations of HBcAg and IL-18 together with IL-12/IFN-alpha 1b. CONCLUSION: IL-18 can induce IFN-gamma secretion and probably play a key role in the modulation of both innate and adaptive immunity. It has implications in improving immunoregulatory effect and increasing the ability of immune cells to kill cells infected by virus.

Adjuvants, Immunologic↗
PubMedDate not supplied

iNOS expression and NO production by neutrophils in cancer patients.

INTRODUCTION: The tumor-polymorphonuclear neutrophil (PMN) relationship can be altered by the release of toxic molecules, such as nitric oxide (NO). The aim of the present study was to examine the expression of the inducible synthase of NO (iNOS)and NO production by human neutrophils of patients with oral cavity cancer. For comparison we performed similar examinations in autologous peripheral blood mononuclear cells (PBMCs). MATERIAL/METHODS: PMNs and PBMCs were isolated from the whole blood of 27 patients with squamous cell carcinoma of the oral cavity. iNOS protein expression in these cells was detected by Western blot. Total nitrite as an indicator of NO concentrations in the culture supernatants and the serum of patients was measured using a colorimetric assay. RESULTS: The PMNs of oral cavity cancer patients showed a significantly lower intensity of iNOS expression than those of healthy controls. The PBMCs of patients showed a more intensive expression of iNOS than the PMNs, but a lower intensity than the PBMCs of the controls. The expression of iNOS in rhIL-6 and rhIL-15-stimulated PMNs and PBMCs of patients increased in comparison with unstimulated cells. We observed lower productions of NO by PMNs and PBMCs of patients than those of the control group. CONCLUSIONS: The results revealed that altered iNOS expression and NO production are more characteristic of PMNs than of PBMCs of patients with oral cavity cancer. Additionally, this study provided new information about IL-6 and IL-15 activity in a tumor-bearing host.

Adult↗
PubMed1996

CD14+ cells in granulocyte colony-stimulating factor (G-CSF)-mobilized peripheral blood mononuclear cells induce secretion of interleukin-6 and G-CSF by marrow stroma.

The ability of granulocyte colony-stimulating factor (G-CSF)-mobilized peripheral blood mononuclear cells (G-PBMCs) to induce secretion of cytokines in primary long-term marrow cultures (LTC) or in the human marrow stromal cell line HS23 was compared with that of marrow mononuclear cells. Equal numbers of G-PBMCs or marrow mononuclear cells were added to stromal cultures, supernatants were harvested at day 4 and levels of interleukin-1 alpha (IL-1 alpha), IL-1 beta, IL-2, IL-6, G-CSF, and tumor necrosis factor alpha (TNF alpha) were determined. G-PBMCs induced 21.4-fold higher levels of IL-6 and 12.5-fold higher levels of G-CSF in LTC cocultures compared with marrow mononuclear cells and induced 20.6-fold more IL-6 and 6.3-fold more G-CSF when added to HS23 cells. Experiments using sorted populations of CD20+, CD3+, and CD14+ cells showed that CD14+ cells within G-PBMCs were responsible for triggering the production of IL-6 and G-CSF. The effect did not require cell-cell contact and was inhibited when neutralizing antibodies to IL-1 alpha and IL-1 beta were used in combination. In these experiments, the greater stimulating ability of G-PBMCs is most likely attributable to the greater number of CD14+ cells in G-PBMCs (26.1+% +/- 2.3%) compared with marrow (2.5% +/- 0.8%), because equal numbers of CD14+ cells sorted from marrow and G-PBMCs showed comparable ability to induce IL-6 and G-CSF when placed directly on stromal cells.

Bone Marrow↗
PubMed1996

Immunization against epitopes in the human melanoma antigen gp100 following patient immunization with synthetic peptides.

gp1OO is a melanocytic lineage-specific antigen recognized by tumor-infiltrating lymphocytes, the adoptive transfer of which is associated with tumor regression in melanoma patients. In this study, peripheral blood mononuclear cells (PBMCs) were harvested from HLA-A2+ melanoma patients before and after immunization with G9-209 (ITDQVPFSY), G9-280 (YLEPGPVTA), or G9-154 (KTWGQYWQV) peptides in Incomplete Freund's Adjuvant and were tested for the ability to be sensitized in vitro using PBMCs pulsed with the native peptides. In addition, PBMCs from patients receiving the G9-209 or G9-280 peptide were stimulated in vitro with peptides modified at anchor residues to enhance binding to HLA-A2: G9-209/2M (IMDQVPFSY) or G9-280-9V (YLEPGPVTV). In patients immunized with G9-209, a single in vitro restimulation with G9-209/2M resulted in the generation of specific antipeptide lymphocytes from seven of seven postimmune PBMCs and only three of seven preimmune PBMCs. In patients immunized with G9-280, a single in vitro restimulation with G9-280/9V resulted in the generation of specific antipeptide lymphocytes from five of six postimmune PBMCs and four of six preimmune PBMCs. In almost all cases, CTLs raised against modified epitopes were capable of recognizing targets displaying the native nonamers. Several anti-G9-209 and anti-G9-209/2M CTLs also demonstrated specific lysis of, and specific IFN-gamma release in response to, gp1OO+-established cell lines. Thus, using peptides modified to enhance immunogenicity for in vitro stimulation improved the sensitivity of immune monitoring of patients immunized with synthetic peptides. These results demonstrate that immunization with a peptide derived from a tumor-associated protein such as gp100 can provoke a measurable antitumor immune response in cancer patients.

Adoptive Transfer↗
PubMed1998

Staphylococcal enterotoxin A-induced injury of human lung endothelial cells and IL-8 accumulation are mediated by TNF-alpha.

Staphylococcal enterotoxin A (SEA), a superantigen produced by some strains of Staphylococcus aureus, causes a variety of clinical manifestations ranging from food poisoning to shock. S. aureus can also be associated with the development of acute respiratory distress syndrome, and SEA has been shown to cause an inflammatory reaction in the lung. Therefore, we examined possible interactions between SEA, PBMCs, polymorphonuclear cells (PMNs), and normal human lung microvascular endothelial cells (HMVEC-L), as well as the role of these interactions on the secretion of IL-8. Injury to HMVEC-L, as measured by the release of 51Cr, increased significantly when HMVEC-L were incubated with SEA and PBMCs. IL-8 was secreted by both PBMCs and HMVEC-L. The accumulation of IL-8 in the culture medium of HMVEC-L was increased by SEA in a dose-dependent manner and was directly related to the number of PBMCs present. Although neither anti-human IL-8 nor IL-1 mAb inhibited HMVEC-L cytotoxicity, anti-human TNF-alpha mAb inhibited both the cytotoxicity and IL-8 accumulation completely. When HMVEC-L were incubated with supernatants from SEA-treated PBMCs, HMVEC-L cytotoxicity was comparable with HMVEC-L incubated with SEA and PBMCs at the same time. Although high concentrations of purified PMNs induced HMVEC-L lysis in a dose-dependent manner, the effect of PMNs was not changed in the presence of SEA. These findings suggest that TNF-alpha secreted by SEA-stimulated PBMCs plays a leading role in HMVEC-L injury.

Antibodies, Monoclonal↗
PubMed2006

Inhibition by mitoxantrone of in vitro migration of immunocompetent cells: a possible mechanism for therapeutic efficacy in the treatment of multiple sclerosis.

BACKGROUND: Damage of the blood-brain barrier and invasion of immunocompetent cells into the central nervous system represent key events in the immunopathogenesis of multiple sclerosis. Mitoxantrone hydrochloride reduces progression of disability and clinical exacerbations in patients with multiple sclerosis. Its precise mode of action is unclear. OBJECTIVE: To investigate the effects of mitoxantrone on the migratory capacity of immunocompetent cells ex vivo and in vitro. DESIGN: Case-control study. SETTING: Department of Neurology, Heinrich Heine University, Düsseldorf, Germany. PARTICIPANTS: Peripheral blood mononuclear cells (PBMCs) were obtained from 11 patients with multiple sclerosis before and after intravenous mitoxantrone treatment; PBMCs from 5 healthy control donors were treated with mitoxantrone in vitro. MAIN OUTCOME MEASURES: The migratory capacity was studied in an in vitro Boyden chamber assay; cells and their rates of migration were analyzed by light microscopy and flow cytometry. To determine the specificity of our findings, PBMCs were treated with perfosfamide in vitro. RESULTS: Mitoxantrone decreased the migratory capacity of CD14(+) monocytes and (to a lesser degree) of CD4(+) and CD8(+) T lymphocytes. These observations were confirmed when control PBMCs were treated with an equivalent dose of mitoxantrone in vitro. Similar effects were seen when PBMCs were preincubated with perfosfamide. The inhibitory effects of mitoxantrone on the migratory capacity of PBMCs were mediated by reduced matrix metalloproteinase 9 activity, as demonstrated by zymography, polymerase chain reaction, and inhibitory studies. CONCLUSION: Mitoxantrone may inhibit the migration of inflammatory cells into and within the central nervous system.

Adult↗
PubMed2006

A role for geranylgeranylation in interleukin-1beta secretion.

OBJECTIVE: Mevalonate kinase deficiency (MKD) is an autosomal-recessive disorder characterized by recurring episodes of inflammation. MK catalyzes the phosphorylation of mevalonic acid, which is an early step in isoprenoid biosynthesis. The goal of our study was to determine whether a temporary shortage of certain isoprenoid end products and/or the accumulation of mevalonic acid is the cause of interleukin-1beta (IL-1beta) secretion in MKD. METHODS: We studied the effect of the addition of intermediate metabolites and inhibitors of the isoprenoid biosynthesis pathway on IL-1beta secretion by peripheral blood mononuclear cells (PBMCs) of patients with MKD and healthy controls. RESULTS: Inhibition of enzymes involved in geranylgeranyl pyrophosphate (GGPP) synthesis or geranylgeranylation of proteins led to a marked increase of lipopolysaccharide-stimulated IL-1beta secretion in PBMCs of control subjects. Furthermore, the increased IL-1beta secretion by PBMCs of patients with MKD was reversed by supplementation with GGPP as well as with mevalonic acid. IL-1beta secretion was increased only when control PBMCs were incubated with excessive amounts of mevalonic acid. Finally, a reduction in IL-1beta secretion by MKD PBMCs was also observed when sterol biosynthesis was inhibited, favoring nonsterol isoprenoid biosynthesis. CONCLUSION: Our results indicate that a shortage of geranylgeranylated proteins, rather than an excess of mevalonate, is likely to cause increased IL-1beta secretion by PBMCs of patients with MKD.

Anti-Inflammatory Agents↗
PubMed2003

Optimal preparation of rhesus macaque blood for cytokine flow cytometric analysis.

BACKGROUND: The rhesus macaque is a common substitute for human subjects in many disease models, including simian immunodeficiency virus, the non-human primate equivalent of the human immunodeficiency virus. Monoclonal antibodies and fluorochromes optimized for use in macaques were included in samples examined for immune responses with the use of intracellular cytokine flow cytometry (CFC). METHODS: Sample preparation was optimized based on the following comparisons: activation of peripheral blood mononuclear cells (PBMCs) versus whole blood; separation of PBMCs using BD Vacutainer cell preparation tubes versus Ficoll; and activation of samples on the day they were collected versus holding samples overnight. RESULTS: When activated with the simian immunodeficiency virus type mac239 and Gag peptide mix or with the superantigen Staphylococcal enterotoxin B, separated PBMCs produced greater CD4 and CD8 fluorescence intensities and a larger percentage of CD69+ cytokine-positive cells than did whole blood samples. PBMCs separated by cell preparation tubes produced absolute T-lymphocyte counts equivalent to that with Ficoll separation, and CFC results with both methods were similar. When subjected to overnight shipping conditions, whole blood and PBMCs sometimes showed a reduction in mean fluorescence intensity and percentage of CD69+ cytokine-positive T lymphocytes. CONCLUSIONS: Due to this reduction in responses, it is preferable to activate samples on the day of blood collection. Samples can be surface stained and frozen in BD FACS Lysing Solution, to be thawed at a later date; this preserves their ability to display a cytokine response. Thus optimal CFC results are achieved by separating macaque PBMCs from whole blood, activating samples on day of collection, and, if necessary, freezing samples after surface staining for future analysis.

Animals↗
PubMed2005

Fixation and cryopreservation of whole blood and isolated mononuclear cells: Influence of different procedures on lymphocyte subset analysis by flow cytometry.

BACKGROUND: Immunophenotyping of whole blood (WB) and isolated peripheral blood mononuclear cells (PBMCs) is a common tool used to evaluate immune system changes in clinical studies. The development of methods that would allow preservation of samples for flow cytometric analysis is important for the extension of this technology to field testing in settings where the equipment might be not readily accessible. METHODS: Three-color flow cytometric analysis was used to determine percentages of T cells and their subsets (CD3(+), CD4(+), CD8(+)), B cells (CD19(+)), and natural killer cells (CD16(+)/56(+)) in WB and PBMCs using variations of a standard stain/fix WB staining procedure (Optilyse) that included staining following fixation and freezing of fixed samples before or after staining. RESULTS: Comparable lymphocyte subset percentages in WB or PBMCs were observed regardless of Optliyse method used (all Ps >/= 0.8). However, differences in fluorescence intensity for several markers were observed across procedures. Compared with the standard stain/fix procedures, fix/stain decreased the mean fluorescence intensities for CD4, CD8, CD19 and CD16/56 in WB and PBMCs (P </= 0.03 for these markers P = 0.105 for CD8 in PBMCs). Further decreases in mean fluorescence intensity were seen with the fix/stain/freeze procedure. The stain/fix/freeze yielded intensities largely comparable to those seen with standard stain/fix procedure (P >/= 0.13), suggesting that, when the markers of interest are known at the time of field collection, implementation of this procedure might be desirable. Fix/freeze/stain resulted in diminution of intensity in general, but they tended to be more modest than those seen for fix/stain/freeze and therefore might be applicable to field studies in instances when the specific markers of interest cannot be defined upfront. CONCLUSIONS: Freezing of fixed WB and PBMCs before or after cell surface staining is a reliable method for preserving specimens in field sites for later determination of lymphocyte subset percentages, which are commonly assessed in immunodeficient and cancer patients.

Blood Preservation↗
PubMed2002

In vitro susceptibility to infection with SIVcpz and HIV-1 is lower in chimpanzee than in human peripheral blood mononuclear cells.

This study was undertaken to evaluate and compare the susceptibility of chimpanzee versus human peripheral blood mononuclear cells (PBMCs) to infection with SIVcpz and HIV-1 non-syncitium inducing primary isolates. The results demonstrate clearly that chimpanzee PBMCs have a lower capacity to support viral replication as compared to human PBMCs. There was no experimental evidence that this difference was due to a lower availability of target cells for viral infection (PBMCs positive for CD4 and CCR5 molecules) or to a differential susceptibility to apoptosis (PBMCs positive for CD4 and CD95 molecules). A lower capacity of chimpanzee PBMCs to support SIVcpz and HIV-1 replication in vitro is related to a post-entry barrier to virus replication.

Animals↗
PubMed2003

Ribavirin inhibits DNA, RNA, and protein synthesis in PHA-stimulated human peripheral blood mononuclear cells: possible explanation for therapeutic efficacy in patients with chronic HCV infection.

The treatment of choice for patients infected chronically with HCV is the combination of IFN-alpha and ribavirin. Monotherapy with ribavirin leads to a clinical and histological improvement, but its exact mechanism of action is unknown. Therefore, the effect of ribavirin on synthesis of inflammatory cytokines and on apoptosis in stimulated peripheral blood mononuclear cells (PBMCs) was investigated. PBMCs were isolated from the blood of HCV infected patients and from healthy volunteers. The effect of ribavirin on IFN-gamma and IL-1beta release in the supernatant of unstimulated and phytohemagglutinin (PHA) stimulated PBMCs was investigated by enzyme linked immunosorbent assay (ELISA). The effect on total DNA, RNA, and protein synthesis was analyzed by measurement of 3H-thymidine, 3H-uridine and 3H-leucine incorporation into cellular macromolecules. Ribavirin led to a dose-dependent decrease of the IFN-gamma but an increase of IL-1beta release into the supernatant of PHA-stimulated PBMCs. At the same time, a dose-dependent decrease of total DNA, RNA, and protein synthesis in cultures of PHA-stimulated PBMCs was demonstrated. These effects could be compensated by the addition of equimolar amounts of guanosine. The rate of apoptotic CD45+ and CD14+ cells in PBMCs cultures increased in a dose-dependent manner. Our data suggest that ribavirin administration to chronically HCV-infected patients could lead to a decrease of the synthesis of proinflammatory cytokines (e.g., IFN-gamma) by an inhibition of total DNA-, RNA-, and protein-synthesis and by induction of apoptosis in the cells of the inflammatory infiltrate. Furthermore, ribavirin could influence the synthesis of viral particles in the hepatocytes.

Antimetabolites↗
PubMed2001

Analysis of HIV drug-resistant quasispecies in plasma, peripheral blood mononuclear cells and viral isolates from treatment-naive and HAART patients.

The pattern of HIV-1 reverse transcriptase and protease mutations conferring resistance to antiretroviral drugs was studied in five treatment-naive patients and five HIV-infected patients receiving HAART [two reverse transcriptase inhibitors + one protease inhibitor] for > or = 1 year. Direct sequencing was performed on plasma HIV RNA, HIV DNA from peripheral blood mononuclear cells (PBMCs), and RNA from viral isolates. In addition, reverse transcriptase and protease PCR products from PBMCs HIV DNA, plasma HIV RNA, and viral isolate RNA were cloned in a plasmid to study the quasispecies distribution of drug-resistance associated mutations. Direct sequencing of HIV DNA from PBMCs and HIV RNA from plasma and viral isolates did not show the presence of drug resistance associated mutations in both reverse transcriptase and protease of HIV from all five treatment-naive patients. On the contrary, mutation analysis obtained by cloning plasma HIV RNA and PBMCs DNA showed the presence of drug-resistance related mutations at a low frequency in both HIV enzymes of four out of five treatment-naive patients. On the other hand, direct sequencing of plasma HIV RNA showed the presence of several reverse transcriptase and protease mutations in all five treated patients. Mutation analysis performed by cloning PBMCs HIV DNA, and HIV RNA from plasma and viral isolates, revealed additional reverse transcriptase and protease changes compared to direct sequencing of the relevant biological samples. All the additional changes were observed in a minority of clones. In conclusion, the data suggest that less frequent drug-resistant viral variants not detected by direct sequencing of PBMCs, plasma samples, or viral isolates are present in both treatment-naive and treatment-experienced HIV patients. These findings may have important implications in the understanding of the selection process of drug-resistant variants under drug pressure.

Adult↗
PubMed1996

Differences in hypervariable region 1 quasispecies of hepatitis C virus between human serum and peripheral blood mononuclear cells.

The complexity of hypervariable region 1 (HVR1) quasispecies of hepatitis C virus (HCV) in serum and peripheral blood mononuclear cells (PBMCs) was assessed at several time points in 11 patients with chronic hepatitis C. Polymerase chain reaction and single-strand conformation polymorphism analysis revealed that four patients (36%) showed serial changes in the complexity of HVR1 quasispecies, which were identical in both serum and PBMCs; two patients (18%) showed both serial changes in quasispecies and differences in quasispecies between serum and PBMCs; and five patients (45%) showed neither serial changes in nor quasispecies differences between serum and PBMCs. These results demonstrate both the existence of different quasispecies between serum and PBMCs and the infection of PBMCs by HCV.

Adult↗
PubMed1995

Effects of cryopreservation on immune responses. VIII. Enhanced secretion of interferon-gamma by frozen human peripheral blood mononuclear cells.

The effect of freezing on phytohemagglutinin-induced interferon-gamma (IFN-gamma) production by human peripheral blood mononuclear cells (PBMCs) was studied. The possible mechanisms responsible for the observed effects were also analyzed. Frozen PBMCs produced significantly larger quantities of IFN-gamma than fresh cells. Like the frozen cells, the monocyte- and natural killer cell-eliminated populations of fresh PBMCs also secreted significantly larger quantities of IFN-gamma. In contrast, the freezing process had no enhancing effect on IFN-gamma production by monocyte-depleted PBMCs. Irradiated PBMCs also secreted larger quantities of IFN-gamma. The results suggest that functional inactivation of a subset of cryosensitive suppressor monocytes is associated with an increase in IFN-gamma production by the T lymphocytes. The results provide further evidence that monocytes mediate their suppressive effect through the activation of a subset of radiosensitive, immuno-down-regulatory T cells. The ability of frozen cells to produce larger quantities of IFN-gamma should be of clinical importance. For instance, cancer patients receiving frozen PBMCs as stem cell support (after myeloablative radio/chemotherapy) should benefit from the increased IFN-gamma secretion because of its potent immunoregulatory, microbicidal, and antitumor activities.

Blood Preservation↗
PubMed1997

Effects of cryopreservation of immune responses. XI. Heightened secretion of tumor necrosis factor-alpha by frozen human peripheral blood mononuclear cells.

In view of the wide usage of frozen PBMCs as stem cell support following high-dose chemo- and/or radiotherapy, and the pleiotropic activities of tumor necrosis factor-alpha (TNF-alpha), the influences of freezing and radiation on LPS-induced TNF-alpha production by human peripheral blood mononuclear cells (PBMCs) were studied. Frozen PBMCs secreted significantly larger quantities of TNF-alpha than fresh cells. Blocking of endogenous IL-10 by neutralization with anti-IL-10 monoclonal antibody resulted in further augmented and prolonged secretion of TNF-alpha by both the fresh and frozen cells. In contrast, addition of exogenous IL-10 to LPS-stimulated cultures inhibited TNF-alpha secretion. In vitro irradiation had an inconsistent effect on TNF-alpha production by the fresh PBMCs. Taken together, these results suggest that the endogenously hypersecreted TNF-alpha is indirectly responsible for the previously reported elevated IL-1-, IL-6-, and IL-10-secreting capabilities of frozen PBMCs. They also indicate that the TNF-alpha induced IL-10 and then down-regulates the monocytes from further TNF-alpha secretion. Considering the vital role played by TNF-alpha in antimicrobial and antitumor activities, in the immune system, and in the pathogenesis of many acute and chronic diseases, the abilities of frozen cells to produce large quantities of TNF-alpha in response to infectious agents could have profound impact on patients receiving such frozen PBMCs as stem cell support following myeloablative therapies.

Antibodies, Blocking↗
PubMed1999

Generation of tumor-specific cytotoxic T lymphocytes by stimulation with HPV type 16 E7 peptide-pulsed dendritic cells: an approach to immunotherapy of cervical cancer.

OBJECTIVE: The aim of this study was to generate HPV-16 E7 peptide-specific cytotoxic T lymphocytes (CTLs) in vitro for future adoptive immunotherapy of cervical cancer. METHODS: Peripheral blood mononuclear cells (PBMC) were isolated from HLA-A2+ healthy donors. The PBMCs were incubated with HPV-16 E7(11-20) peptide and varying cytokines in the primary culture. Restimulation was performed weekly with peptide-pulsed, irradiated autologous PBMCs. Alternatively, the PBMCs were depleted of abundant CD4+ cells and stimulated with HPV-16 E7(11-20) peptide-pulsed dendritic cells. Cytolytic activity was determined by a standard 4-h (51)Cr-release assay. RESULTS: After 6 weeks in culture, we were able to establish peptide-specific CTL lines in one of seven donors by incubating PBMCs with HPV-16 E7(11-20) peptide. When we employed autologous peptide-pulsed dendritic cells to stimulate CD8+ cell-enriched PBMCs, we obtained CTL lines in four of seven donors. The primed CTLs were able to lyse the HLA-A2+ and HPV-16+ cervical cancer cell line Caski. SiHa, an HLA-A2-, but HPV 16+, cervical cancer cell line could be lysed only after transfection with HLA-A2. In addition, a high cytotoxicity (>80%) was obtained against peptide-pulsed, but not unpulsed, targets such as autologous Ebstein-Barr virus-immortalized B cells or allogeneic lipopolysaccaride-stimulated PBMCs. DCs were clearly the most potent of all tested antigen presenting cells to stimulate a CTL response in a proliferation assay. CONCLUSION: HPV-16 E7 peptide-specific CTLs could be generated in vitro. A practical protocol to expand the CTLs to a sufficient number for an application in a clinical trial is in progress.

Dendritic Cells↗
PubMed1996

Preliminary in vitro growth cycle and transmission studies of HIV-1 in an autologous primary cell assay of blood-derived macrophages and peripheral blood mononuclear cells.

Recent interest focused on the dynamics of HIV-1 replication in primary monocytes/macrophages and T-lymphocytes of the immune system, as well as the standardization of virological and immunological in vitro assays with primary isolates, provided the impetus for these studies. These types of studies have never been performed as they would occur in vivo, i.e., where the envelope of the virus and cell membranes of the two cell types of the same host origin. Therefore, the biological and physicochemical properties of an uncloned, primary dual-tropic isolate HIV-1ADA during the initial lag, log, and stationary phases of viral replication were studied in an autologous donor cell assay in peripheral blood mononuclear cells (PBMC) and blood monocyte-derived macrophages (MDM). Similar total numbers (10(9) virus particles/ml) were produced by both cell types during the stationary period. On a per cell per day basis, during peak stationary periods, 0.92 x 10(3) virions/day for MDMs and 5.31 x 10(3) virions/day for PBMCs were produced. Interestingly, virus replicating from MDMs during the log-growth phase demonstrated the greatest infectious fraction which was 3 logs greater than virus replicating in PBMCs. Despite constant virus particle production in MDMs, the infectious fraction was found to fall 3 to 4 logs over a 10-day period. Due to an infectious fraction less than 1 (0.053 infectious unit/cell/24 hr), virus spread in PBMCs during the rapid log phase could only have occurred by cell-to-cell contact, whereas in MDMs with an infectious fraction of about one infectious particle (approximately 1/cell/24 hr), cell-free transmission could account for the observed results. Most of the MDMs (> 90%) became productively infected, whereas only 5-10% of the total PBMCs were found replicating virus. The period of peak stationary virus production (i.e., stationary phase) was at minimum 4 to 5 times longer in MDMs than PBMCs. Whereas the majority of p24, RT, and gp 120 found to be associated with MDM-derived virions, no increased dissociation of these components was observed in PBMC-derived virions. The virion-associated gp 120 was 3 to 4 times more stable on both PBMC- and MDM-derived virus (> 96 hr) and present at 10-25 times the concentration per virion than that observed for a T-cell-line-adapted laboratory strain of HIV-1 replicating in T-cell lines. These in vitro results suggest that important differences exist between MDMs and PBMCs with regard to the viral dynamics of infection and replication which should provide for a qualitative and quantitative basis to estimate virus replication on a per-cell basis for other known cellular targets of HIV-1. Studying the multiple biophysicochemical characteristics and viral replication dynamics as described herein provides an autologous in vitro model of additional quantifiable parameters for analysis and understanding of virus/host factor(s) and/or antivirals which influence them.

Cell Separation↗