Tissue Cell Suspensions Research Articles

Unbiased method for spectral analysis of cells with great diversity of autofluorescence spectra.

Autofluorescence is an intrinsic feature of cells, caused by the natural emission of light by photo-excitatory molecular content, which can complicate analysis of flow cytometry data. Different cell types have different autofluorescence spectra and, even within one cell type, heterogeneity of autofluorescence spectra can be present, for example, as a consequence of activation status or metabolic changes. By using full spectrum flow cytometry, the emission spectrum of a fluorochrome is captured by a set of photo detectors across a range of wavelengths, creating an unique signature for that fluorochrome. This signature is then used to identify, or unmix, that fluorochrome's unique spectrum from a multicolor sample containing different fluorescent molecules. Importantly, this means that this technology can also be used to identify intrinsic autofluorescence signal of an unstained sample, which can be used for unmixing purposes and to separate the autofluorescence signal from the fluorophore signals. However, this only works if the sample has a singular, relatively homogeneous and bright autofluorescence spectrum. To analyze samples with heterogeneous autofluorescence spectral profiles, we setup an unbiased workflow to more quickly identify differing autofluorescence spectra present in a sample to include as "autofluorescence signatures" during the unmixing of the full stained samples. First, clusters of cells with similar autofluorescence spectra are identified by unbiased dimensional reduction and clustering of unstained cells. Then, unique autofluorescence clusters are determined and are used to improve the unmixing accuracy of the full stained sample. Independent of the intensity of the autofluorescence and immunophenotyping of cell subsets, this unbiased method allows for the identification of most of the distinct autofluorescence spectra present in a sample, leading to less confounding autofluorescence spillover and spread into extrinsic phenotyping markers. Furthermore, this method is equally useful for spectral analysis of different biological samples, including tissue cell suspensions, peripheral blood mononuclear cells, and in vitro cultures of (primary) cells.

Periodontitis contributes to COPD progression via affecting ferroptosis

BackgroundPeriodontitis has emerged as a potential risk factor for chronic obstructive pulmonary disease (COPD). However, the precise mechanism through which periodontitis influences the progression of COPD requires further investigation. Ferroptosis is one of the crucial pathogenesis of COPD and recent researches suggested that periodontitis was associated with ferroptosis. Nonetheless, the relationship among periodontitis, COPD and ferroptosis remains unclear. This study aimed to elucidate whether periodontitis contributes to COPD exacerbation and to assess the potential impact of ferroptosis on periodontitis affecting COPD.MethodsThe severity of COPD was assessed using Hematoxylin and eosin (H&E) staining and lung function tests. Iron assays, malondialdehyde (MDA) measurement and RT-qPCR were used to investigate the potential involvement of ferroptosis in the impact of periodontitis on COPD. Co-cultures of periodontitis associated pathogen Phophyromonas gingivalis (P. gingivalis) and lung tissue cells were used to evaluate the effect of P. gingivalis on inducing the ferroptosis of lung tissue via RT-qPCR analysis. Clinical Bronchoalveolar Lavage Fluid (BALF) samples from COPD patients were collected to further validate the role of ferroptosis in periodontal pathogen-associated COPD.ResultsPeriodontitis aggravated the COPD progression and the promotion was prolonged over time. For the first time, we demonstrated that periodontitis promoted the ferroptosis-associated iron accumulation, MDA contents and gene expressions in the COPD lung with a time-dependent manner. Moreover, periodontitis-associated pathogen P. gingivalis could promote the ferroptosis-associated gene expression in single lung tissue cell suspensions. Clinical BALF sample detection further indicated that ferroptosis played essential roles in the periodontal pathogen-associated COPD.ConclusionPeriodontitis could contribute to the exacerbation of COPD through up-regulating the ferroptosis in the lung tissue.

Cancer cell intrinsic TIM-3 induces glioblastoma progression

Glioblastoma (GBM) is identified to share common signal pathways between glioma and immune cells. Here, we find that Tcell immunoglobulin domain and mucin domain protein 3 (TIM-3) is one of the most common co-inhibitory immune checkpoints in GBM shared by tumor and non-tumor cells. Glioma cell-intrinsic TIM-3 is involved in not only regulating malignant behaviors of glioma cells but also inducing macrophage migration and transition to anti-inflammatory/pro-tumorigenic phenotype by a TIM-3/interleukin 6 (IL6) signal. In mechanism, as one of the major regulators of IL6, TIM-3 regulates its expression through activating NF-κB. Blocking this feedback loop by Tocilizumab, an IL6R inhibitor, inhibited the above effects and repressed the tumorigenicity of GBM invivo. Our work identifies glioma cell-intrinsic functions of TIM-3/IL6 signal mediating the crosstalk feedback loop between glioma cells and tumor-associated macrophages (TAMs). Blocking this feedback loop may provide a novel therapeutic strategy for GBM.

Association of synovial tissue polyfunctional T-cells with DAPSA in psoriatic arthritis

ObjectiveThis study examines polyfunctional T-cells in psoriatic arthritis (PsA) synovial tissue and their associations with clinical disease and implications for therapy.MethodsPsA synovial tissue was enzymatically/mechanically digested to generate synovial tissue...

A Simple and Effective Method for Flow Cytometric Study of Lymphoid Malignancies Using Needle Core Biopsy Specimens.

We developed a simple and effective rinsing technique (RT) of needle biopsies to produce cell suspensions for flow cytometry (FCM) and evaluated whether the RT is comparable to the conventional tissue cell suspension (TCS) technique. We retrieved 93 needle core biopsy cases employing the RT for FCM and 25 needle biopsy cases using TCS for FCM. The diagnostic concordance between the FCM results and the morphologic diagnoses of both groups was compared. The diagnostic concordance was comparable in the RT group (92.6%) to the TCS group (71.4%). Furthermore, the diagnostic concordance in the RT group was associated with number of isolated cells. The diagnostic accuracy increased significantly when the cell number was above 30,000 in the RT group. The RT for FCM not only maximizes the tissue utilization, but also is a simple and effective method to obtain cell suspension as compared to traditional cell suspension technique. © 2018 International Clinical Cytometry Society.

An iNKT cell expansion causes premature delivery in mice (HUM7P.323)

Abstract Objective: Maternal-fetal tolerance involves a tight balance between the innate and adaptive immunity, which avoids rejection of the semi-allogeneic embryo. The innate and adaptive limbs of the immune response are bridged by iNKT cells; therefore, we hypothesized that an alteration in their number and/or activation breaks maternal-fetal tolerance, leading to premature delivery. Methods: Pregnant mice were injected on E16.5 with either α-galactosylceramide (an iNKT activator; 2 μg) or PBS as a control (n=19 each). Gestational length and the rates of stillbirth and long-term pup survival were recorded. Peripheral blood, decidua, liver, spleen and lymph nodes were collected just prior to delivery from additional treated and control mice (n=8-9 each). In tissue cell suspensions, iNKT phenotype and activation were analyzed by flow cytometry. Results: 1) iNKT activator treatment promoted premature delivery (E18.09±0.60; controls delivered on E19.51±0.78); 2) iNKT activator treatment increased the rate of stillbirth (63.63 vs. 21.94%); 3) iNKT activator treatment did not reduce long-term pup survival; 4) iNKT activator treatment caused an expansion of iNKT cells (CD1d tetramer+NK1.1+CD49b+) in peripheral blood, liver and decidua, but not in spleen and lymph nodes; 5) iNKT cell activation was unchanged by iNKT activator treatment. Conclusion: Treatment with α-galactosylceramide causes an expansion of systemic and local iNKT cells leading to premature delivery in mice.

Vascular endothelial growth factor receptor 1 expression in nasal polyp tissue

Edema represents a key feature of nasal polyp (NP) disease. Members of the vascular endothelial growth factor (VEGF) family may be involved, but the precise role of VEGF-A, VEGF-B, placental growth factor (PlGF), and their receptors VEGFR1 and VEGFR2 in NP edema formation remains elusive. Exploring the expression of VEGF family members and their receptors and their correlation with clinical, radiological, and edema markers in NP. The expression of VEGF-A, VEGF-B, PlGF, VEGFR1, and VEGFR2 was measured in NP (n=23) and control tissue (n=22) at mRNA and protein level. Edema was evaluated by measuring albumin levels and wet/dry ratios. Computed tomography (CT) scans were scored using the Lund-Mackay scoring system. IL-5 mRNA expression was determined by real-time RT-PCR. Cell suspensions from NP (n=10) and control tissue (n=12) were stimulated in vitro with IL-1β or TNFα. mRNA expression of VEGFR1 and VEGF-B was significantly higher in NP compared with control tissue. Expression levels of VEGF-B and VEGFR1 significantly correlated with NP albumin content (VEGF-B: P=0.0208; VEGFR1: P=0.0293), CT scan scores (VEGF-B: P=0.0075; VEGFR1: P=0.0068), and IL-5 mRNA (VEGF-B: P=0.0027; VEGFR1: P=0.0001). In vitro stimulation of control and NP tissue cell suspensions with IL-1β or TNFα significantly reduced the expression of VEGFR2 in control tissue, without altering VEGFR1 and VEGF-B expression. hVEGF-B induced nitric oxide production in NP macrophages (P<0.05). Expression levels of VEGFR1 and VEGF-B correlate with edema and clinical markers of NP disease and therefore represent potential therapeutic targets.

Measuring Bacterial Load and Immune Responses in Mice Infected with &lt;em&gt;Listeria monocytogenes&lt;/em&gt;

Listeria monocytogenes (Listeria) is a Gram-positive facultative intracellular pathogen1. Mouse studies typically employ intravenous injection of Listeria, which results in systemic infection2. After injection, Listeria quickly disseminates to the spleen and liver due to uptake by CD8α+ dendritic cells and Kupffer cells3,4. Once phagocytosed, various bacterial proteins enable Listeria to escape the phagosome, survive within the cytosol, and infect neighboring cells5. During the first three days of infection, different innate immune cells (e.g. monocytes, neutrophils, NK cells, dendritic cells) mediate bactericidal mechanisms that minimize Listeria proliferation. CD8+ T cells are subsequently recruited and responsible for the eventual clearance of Listeria from the host, typically within 10 days of infection6.Successful clearance of Listeria from infected mice depends on the appropriate onset of host immune responses6 . There is a broad range of sensitivities amongst inbred mouse strains7,8. Generally, mice with increased susceptibility to Listeria infection are less able to control bacterial proliferation, demonstrating increased bacterial load and/or delayed clearance compared to resistant mice. Genetic studies, including linkage analyses and knockout mouse strains, have identified various genes for which sequence variation affects host responses to Listeria infection6,8-14. Determination and comparison of infection kinetics between different mouse strains is therefore an important method for identifying host genetic factors that contribute to immune responses against Listeria. Comparison of host responses to different Listeria strains is also an effective way to identify bacterial virulence factors that may serve as potential targets for antibiotic therapy or vaccine design.We describe here a straightforward method for measuring bacterial load (colony forming units [CFU] per tissue) and preparing single-cell suspensions of the liver and spleen for FACS analysis of immune responses in Listeria-infected mice. This method is particularly useful for initial characterization of Listeria infection in novel mouse strains, as well as comparison of immune responses between different mouse strains infected with Listeria. We use the Listeria monocytogenes EGD strain15 that, when cultured on blood agar, exhibits a characteristic halo zone around each colony due to β-hemolysis1 (Figure 1). Bacterial load and immune responses can be determined at any time-point after infection by culturing tissue homogenate on blood agar plates and preparing tissue cell suspensions for FACS analysis using the protocols described below. We would note that individuals who are immunocompromised or pregnant should not handle Listeria, and the relevant institutional biosafety committee and animal facility management should be consulted before work commences.

Measuring Bacterial Load and Immune Responses in Mice Infected with &lt;em&gt;Listeria monocytogenes&lt;/em&gt;

Listeria monocytogenes (Listeria) is a Gram-positive facultative intracellular pathogen1. Mouse studies typically employ intravenous injection of Listeria, which results in systemic infection2. After injection, Listeria quickly disseminates to the spleen and liver due to uptake by CD8α+ dendritic cells and Kupffer cells3,4. Once phagocytosed, various bacterial proteins enable Listeria to escape the phagosome, survive within the cytosol, and infect neighboring cells5. During the first three days of infection, different innate immune cells (e.g. monocytes, neutrophils, NK cells, dendritic cells) mediate bactericidal mechanisms that minimize Listeria proliferation. CD8+ T cells are subsequently recruited and responsible for the eventual clearance of Listeria from the host, typically within 10 days of infection6. Successful clearance of Listeria from infected mice depends on the appropriate onset of host immune responses6 . There is a broad range of sensitivities amongst inbred mouse strains7,8. Generally, mice with increased susceptibility to Listeria infection are less able to control bacterial proliferation, demonstrating increased bacterial load and/or delayed clearance compared to resistant mice. Genetic studies, including linkage analyses and knockout mouse strains, have identified various genes for which sequence variation affects host responses to Listeria infection6,8-14. Determination and comparison of infection kinetics between different mouse strains is therefore an important method for identifying host genetic factors that contribute to immune responses against Listeria. Comparison of host responses to different Listeria strains is also an effective way to identify bacterial virulence factors that may serve as potential targets for antibiotic therapy or vaccine design. We describe here a straightforward method for measuring bacterial load (colony forming units [CFU] per tissue) and preparing single-cell suspensions of the liver and spleen for FACS analysis of immune responses in Listeria-infected mice. This method is particularly useful for initial characterization of Listeria infection in novel mouse strains, as well as comparison of immune responses between different mouse strains infected with Listeria. We use the Listeria monocytogenes EGD strain15 that, when cultured on blood agar, exhibits a characteristic halo zone around each colony due to β-hemolysis1 (Figure 1). Bacterial load and immune responses can be determined at any time-point after infection by culturing tissue homogenate on blood agar plates and preparing tissue cell suspensions for FACS analysis using the protocols described below. We would note that individuals who are immunocompromised or pregnant should not handle Listeria, and the relevant institutional biosafety committee and animal facility management should be consulted before work commences.

V‐region gene analysis of locally defined synovial B and plasma cells reveals selected B cell expansion and accumulation of plasma cell clones in rheumatoid arthritis

To elucidate the development of synovial tissue-specific B cell immune responses, the clonality of individual naive B cells, memory B cells, and plasma cells and their organization and histologic localization in the inflamed tissue were investigated in patients with rheumatoid arthritis (RA). B and plasma cells were isolated by laser capture microdissection (LCM) from the synovial tissue of patients with RA. In addition, single naive B cells, memory B cells, and plasma cells were sorted from synovial tissue cell suspensions. RNA was extracted from the cells, and Ig VH genes were amplified, cloned, and sequenced. Both LCM and single cell sorting analyses showed that naive and memory B cells infiltrated the RA synovial tissue. Comparison of the V-gene repertoire of B and plasma cells suggested that synovial plasma cells were generated, by and large, from locally activated B cells, indicating that a selected population of memory B cells differentiates into large plasma cell clones that then accumulate in the inflamed tissue. Clonally related plasma cells were isolated from separate and distinct localized areas of the tissue, suggesting that the newly generated plasma cells have a high migratory capacity. These results support the idea of a continuous activation of selected B cell clones, and hence a massive accumulation of plasma cells, in RA synovial tissue. As B cells and their secreted antibodies are an important factor in controlling inflammatory processes, patients with RA displaying intensive synovial tissue lymphocytic infiltrations might benefit from B cell depletion therapy. Early treatment will prevent accumulation of pathogenic plasma cells.

Local and Systemic Induction of an Abundant CD4+CD25+ Regulatory T Cell Population by Non-Hodgkin's Lymphoma.

Regulatory T (Treg) cells contribute to immune evasion by malignancies. To investigate their importance in non-Hodgkin's lymphoma (NHL), we enumerated Treg cells in peripheral blood mononuclear cells (PBMC) and involved tissues from 30 newly diagnosed patients. CD25+FoxP3+CD127lowCD4+ Treg cells were increased markedly in PBMC (median=20.4% CD4 T cells, n=20) versus healthy controls (median=3.2%, n=13; p<0. 001, rank sum test) and correlated with serum lactate dehydrogenase (n=14; Rs=0.79, p <0.0001) and disease stage. The median Treg percentage of CD4 T cells from early stages (Ann Arbor stage I and II, n=4) was 12.2%, whereas it was 25.4% in advanced disease (Ann Arbor stages III, IV or bulky stage II, ≥5cm, n=10; p =0.013). We also enumerated Tr1 cells, both in peripheral blood and involved tissue samples, and again compared with healthy controls but no significant differences were noted. We documented poor proliferation of T cells with mitogen ConA and almost none with recall antigens PPD and DPT in both PBMC and involved tissue samples (n=9). T cell hyporesponsiveness was reversed by depleting CD25+ cells (n=4), or by adding anti-CTLA-4 (n=3), supporting the view that Treg cells explain the systemic immunosuppression seen in NHL. A high proportion of Treg cells was also present in involved tissues (median=38.8% CD4 T cells, n=15) versus reactive nodes (median=11.6%, n=2, p=0.02). Therefore, we tested the hypothesis that a regulatory phenotype is induced from conventional T cells within the tumor microenvironment. When autologous CD25- PBMC fractions were incubated with tumor cells from patients (n=6) in vitro, there was consistent strong induction and then expansion of cells with the CD4+CD25+FoxP3+ phenotype of classic ‘natural' Treg cells as indicated by CFSE dilution. This induction was dependent on tumor dose and was seen when we depleted lymphoid dendritic cells from the involved tissue cell suspension using anti-CD304, or enriched the tumor cells by positive selection of CD20+ cells. This population was confirmed to be suppressive in function (n=3). We also investigated the mechanisms of this induction. Both cell-cell contact and soluble factors appeared important. In two of four cases, some induction was also noted with transwell experiments or with tumor cell conditioned supernatant, indicating that in these cases soluble factors are also involved apart from direct cell-cell contact mechanism. Reports elsewhere suggest roles for prostaglandin E2, tryptophan catabolism, IL-9 and PD-1 interaction with its ligands in inducing a Treg phenotype. Thus, we used cyclooxygenase inhibitors aspirin and sulindac, the indoleamine 2, 3-dioxygenase (IDO) inhibitor 1-methyl tryptophan (1MT), anti-IL-9 receptor antibody and blocking anti-PDL-1 or anti-PDL-2 antibodies in four samples. None of these reagents inhibited Treg induction apart from one case where both anti-PDL-1 and anti-PDL-2 blocking antibodies inhibited Treg induction. We conclude that NHL cells are powerful inducers of Treg cells, which may represent a new therapeutic target.

A Soluble BAFF Antagonist, BR3-Fc, Decreases Peripheral Blood B Cells and Lymphoid Tissue Marginal Zone and Follicular B Cells in Cynomolgus Monkeys

BAFF (also known as BLyS), a member of the tumor necrosis factor superfamily, plays a critical role in the maturation and development of B cells. BAFF has three receptors on B cells, the most crucial of which is BR3. In this study, we demonstrate the biological outcome of BAFF blockade in cynomolgus monkeys using a soluble fusion protein consisting of human BR3 and human IgG1 Fc. In vitro, BR3-Fc blocked BAFF-mediated survival and proliferation of cynomolgus monkey B cells. Weekly treatment of cynomolgus monkeys with BR3-Fc for 13 to 18 weeks resulted in significant B-cell reduction in the peripheral blood and in lymphoid organs. CD21(high) B cells in lymphoid tissues, a subset analogous to human marginal zone B cells, expressed nearly twofold higher BR3 levels than did CD21(med) B cells. Lymphoid tissue flow cytometric analysis showed that BR3-Fc reduced this CD21(high) B-cell subset to a greater extent than it reduced CD21(med) B cells. Dual-label immunohistochemistry and morphometric image analysis supported these results by demonstrating that BR3-Fc reduced a significant proportion of the B cells within the splenic inner and outer marginal zones. These findings should prove very useful in guiding the desired therapeutic use of BR3-Fc for autoimmune diseases in the clinic.

Immunological and regulatory functions of uninfected and virus infected immature and mature subtypes of dendritic cells--a review.

In 1868, dendritic cells (DCs) were discovered in human skin by Paul Langerhans using gold staining. These cells were named Langerhans cells (LCs) after their discoverer who, due to their dendrites, regarded them as neurons. One hundred and eleven years were to pass until it was discovered that in vertebrates these cells originate in the bone marrow as monocytes. In the 1980s, DC research was mostly carried out on DCs that are present in different tissues of mice and humans. These studies revealed that after interaction with foreign antigens, skin LCs/DCs migrate through the lymph vessels to the draining lymph nodes and induce the two arms of the immune response. The isolation of DCs from tissue cell suspensions opened the way to studies on the cells' surface proteins and their ability to stimulate immune responses. During the 1990s, studies revealed the role of DCs in the activation of naive T cells in the lymph nodes and the regulatory properties of DCs in lymph nodes, thymus, gut, and spleen. Part A of the review deals with the DC system of human and mice and immunological and regulatory functions of subsets of DCs in the skin with reference to migrating and stationary DCs, as well as the connection between DCs and the nervous system. Furthermore, the origin of both follicular DCs that are present in lymphoid tissues and thymic DCs are discussed. Part B is devoted to virus infections of DCs with an emphasis on infections caused by human herpes viruses. Part C presents the modulation of DC gene expression in response to the influenza virus. Contemporary research focuses on the role of DCs in the immune systems of vertebrates. Moreover, studies are being conducted on the regulatory functions of DCs by tissue cells in different organs of vertebrates.

Antisense Oligodeoxynucleotide Combination Therapy of Primary Chronic Myelogenous Leukemia Blast Crisis in SCID Mice

The proliferation of chronic myelogenous leukemia (CML) cells and the transformation of normal hematopoietic cells by BCR-ABL appear to require the expression of a functional MYC protein, suggesting an approach to treatment of Philadelphia leukemias based on simultaneous targeting of BCR-ABL and c-MYC. To test this hypothesis, CML-blast crisis (CML-BC) primary cells were treated in vitro with bcr-abl and c-myc antisense phosphorothioate oligodeoxynucleotides ([S]ODNs), individually or in combination. Compared with antisense ODNs targeting of individual oncogenes, downregulation of both BCR-ABL and c-MYC by specific antisense [S]ODNs resulted in a synergistic antiproliferative effect. Colony formation of normal bone marrow cells was not affected by either treatment. To assess the therapeutic potential of multiple oncogene downregulation, SCID mice injected with CML-BC primary cells were treated systematically with equal doses of bcr-abl or c-myc antisense [S]ODNs or with a combination of both antisense [S]ODNs. Compared with mice treated with individual compounds, the disease process was significantly retarded in the group treated with both [S]ODNs as revealed by flow cytometry, clonogenic assay, and RT-PCR analysis to detect leukemic cells in mouse tissue cell suspensions. These effects correlated with a markedly increased survival of leukemic mice treated with both antisense [S]ODNs. Leukemic cells harvested from antisense [S]ODN-treated mice were sensitive to the effects of antisense [S]ODNs in vitro, suggesting that the treatment can be successfully repeated. These data demonstrate the therapeutic potential of targeting multiple cooperating oncogenes.

Antisense oligodeoxynucleotide combination therapy of primary chronic myelogenous leukemia blast crisis in SCID mice

The proliferation of chronic myelogenous leukemia (CML) cells and the transformation of normal hematopoietic cells by BCR-ABL appear to require the expression of a functional MYC protein, suggesting an approach to treatment of Philadelphia leukemias based on simultaneous targeting of BCR-ABL and c-MYC. To test this hypothesis, CML-blast crisis (CML-BC) primary cells were treated in vitro with bcr-abl and c- myc antisense phosphorothioate oligodeoxynucleotides ([S]ODNs), individually or in combination. Compared with antisense ODNs targeting of individual oncogenes, downregulation of both BCR-ABL and c-MYC by specific antisense [S]ODNs resulted in a synergistic antiproliferative effect. Colony formation of normal bone marrow cells was not affected by either treatment. To assess the therapeutic potential of multiple oncogene downregulation, SCID mice injected with CML-BC primary cells were treated systematically with equal doses of bcr-abl or c-myc antisense [S]ODNs or with a combination of both antisense [S]ODNs. Compared with mice treated with individual compounds, the disease process was significantly retarded in the group treated with both [S]ODNs as revealed by flow cytometry, clonogenic assay, and RT-PCR analysis to detect leukemic cells in mouse tissue cell suspensions. These effects correlated with a markedly increased survival of leukemic mice treated with both antisense [S]ODNs. Leukemic cells harvested from antisense [S]ODN-treated mice were sensitive to the effects of antisense [S]ODNs in vitro, suggesting that the treatment can be successfully repeated. These data demonstrate the therapeutic potential of targeting multiple cooperating oncogenes.

Leukemia treatment in severe combined immunodeficiency mice by antisense oligodeoxynucleotides targeting cooperating oncogenes.

Transformation of hematopoietic cells by the p210bcr/abl tyrosine kinase appears to require the expression of a functional MYC protein, suggesting that simultaneous targeting of BCR-ABL and c-myc might be a rational strategy for attempting treatment of Phil-adelphia leukemia. To test this hypothesis, severe combined immunodeficiency mice injected with Philadelphia leukemic cells were treated systemically with equal doses of bcr-abl or c-myc antisense oligodeoxynucleotides (ODNs) or with both ODNs in combination. Compared with the mice treated with individual agents, the disease process was much slower in the group treated with both ODNs, as revealed by flow cytometry, clonogenic assay, and reverse transcriptase-polymerase chain reaction analysis to detect leukemic cells in mouse tissue cell suspensions, and by enumeration of liver metastases. The retardation of the disease process was positively correlated with a markedly increased survival of leukemic mice treated with both ODNs. These data demonstrate the therapeutic potential of targeting multiple cooperating oncogenes.

Immunopanning and Developmental Stage-Specific Primary Culture of Oligodendrocyte Progenitors (O4+GalC−) Directly from Postnatal Rodent Cerebrum

An immunopanning technique for capturing the immediate progenitors of oligodendrocytes (OLs) that first appear In developing rat cerebrum at P4-P5 is described. Identified with two monoclonal antibodies, O4 and anti-galactocerebroside (GalC), these progenitors have the surface antigenic phenotype O4+GalC−. Their isolation from dissociated cell suspensions of tissue begins with a negative immunoselection step using antibody-mediated complement lysis to remove O4+ cells (15%) that have already differentiated to become GalC+ OLs at the time of dissociation. The remaining progenitors are labeled with monoclonal antibody 04, and 04+ cells are bound to a secondary antibody-coated polystyrene dish. After nonadherent cells are washed away, O4+GalC− progenitors are recovered and placed into primary culture. Yields of 3-4 × 105 progenitors per cerebrum are obtained with >90% viability and 95% purity. Culturing the progenitors in a defined, insulin-containing medium conditioned by type 1 astrocytes promotes extensive differentiation and long-term cell survival. Marked differences in the time course of progenitor accumulation and efficacy of immunopanning indicate that purification of O4+GalC− progenitors from regions other than cerebrum is necessary for some strains of mice.

Continuous interleukin-2 and tumor-infiltrating lymphocytes as treatment of advanced melanoma. A national biotherapy study group trial

Melanoma metastases were harvested from 82 patients for the purpose of growing and expanding tumor-infiltrating lymphocytes (TIL). Tumor tissue cell suspensions were incubated with interleukin-2 (IL-2), followed by repeated exposure to tumor antigen with or without OKT3 monoclonal antibody (MoAb). Initial growth success was achieved in 56 of 82 cultures (72%). Efforts were made to expand 26 of these 56 cultures for therapeutic TIL; 23 of 26 early cultures (88%) were successfully expanded for in vivo therapy. It took a mean of 78.5 +/- 25.4 days to grow sufficient TIL for treatment. Therapy included cyclophosphamide (1 g/m2) on day 1, followed by a 96-hour continuous infusion of IL-2 (18 x 10(6) IU/m2/d) on days 2 to 5, and approximately 10(11) (mean 1.49 +/- 0.93 x 10(11)) TIL on day 2. Patients who responded received monthly IL-2 as a 96-hour infusion. Median patient age was 45 years of age. Sixty-seven percent of the patients were men. Performance status was 0 to 1 in 77% of patients. Thirty-four percent of the patients had liver metastases. The usual IL-2 toxicities were seen. Response rate for 21 patients was 24% (95% confidence interval, 10% to 49%). One complete response was achieved with cells 98% CD4+; four partial responses were achieved with cells 80%, 94%, 98%, and 98% CD8+, respectively. Four of eight patients who received TIL, which had never been stimulated with OKT3, had tumor response. The authors conclude that a treatment plan for IL-2/TIL is technically difficult, costly, and effective for only a minority of patients. Overall, clinical results are not clearly superior to those obtained with other IL-2 regimens.

Detection of eosinophils using an eosinophil peroxidase assay. Its use as an assay for eosinophil differentiation factors

A colorimetric assay for peroxidase has been applied to the detection of eosinophils in bone marrow cultures and tissue cell suspensions. The substrate solution consists of 0.1 mM o-ophenylenediamine in 0.05 M Tris-HCl buffer pH 8.0 containing 0.1% Triton and 1 mM hydrogen peroxide. The method is shown to be an easy and reproducable method of detecting eosinophils, with insignificant interference from neutrophils.

Action on ricin and its polypeptide chains on cultured hepatoma cells.

The effect of ricin, the glycoproteic toxin from castor beans, as well as of its two polypeptide chains A and B, was studied on hepatoma tissue cell suspension cultures (HCT). The isolated A and B chains have no action. Ricin at a 0.3 microgram/ml concentration, for 3 x 10(5) cells/ml, has a cytostatic effect which becomes cytotoxic after 72 h. This effect exists even if the cells are preincubated for 4 with ricin and washed afterwards. The protein content of the ricin-treated cells decreases. Protein synthesis measured by the incorporation of [3H]-leucine in the cell proteins begins to be inhibited after 30 min and is completely blocked after 2 h for a ricin concentration of 0.3 microgram/ml. DNA synthesis is inhibited from 1 h on. Finally the level of the DNA slows down from 3 h on, whereas the level of RNA abruptly falls between 4 and 5 h. The inhibitory effects are likely to be a consequence of protein synthesis inhibition, but a direct effect on the nucleic acids is not excluded.