Simultaneous quantitation of 15 cytokines using a multiplexed flow cytometric assay

Differences in immunological alterations and underlying viral infections in two well-defined severe drug eruptions

BACKGROUND

Similar drugs (e.g. anticonvulsants) have been implicated in the development of two distinct forms of severe cutaneous drug reactions, Stevens-Johnson syndrome (SJS)/toxic epidermal necrolysis (TEN) and drug-induced hypersensitivity syndrome (DIHS)/drug rash with eosinophilia and systemic symptoms (DRESS).

AIM

To investigate immunological alterations and underlying viral infections that could contribute to the variability in the clinical presentations of these diseases.

METHODS

We retrospectively analysed clinical variables, serum immunoglobulin levels, numbers of circulating white blood cells, lymphocytes and their subsets, serum levels of several cytokines, and underlying viral infections in both drug reactions, using samples obtained at onset from 9 patients with SJS/TEN and 19 patients with DIHS/DRESS.

RESULTS

There were significant differences between the two drug eruptions in the duration of drug intake before onset, the levels of IgG, IgA and IgM, the numbers of circulating white blood cell, lymphocyte, CD3+ T cell and CD8+ T cells, the serum levels of interferon-γ, and the titres of anti-herpes simplex virus IgG at onset.

CONCLUSIONS

The difference in the pattern of immune responses shaped in part by previous and underlying viral infections at the time of drug exposure could cause a marked deviation in the pathological phenotype of severe drug eruptions. Elucidating these host factors may provide a basis for therapeutic approaches in patients with severe drug reactions.

Snapshots of protein dynamics and post-translational modifications in one experiment--beta-catenin and its functions

β-catenin plays multiple roles in the canonical Wnt signaling pathway and in cell-cell adhesion complexes. In addition, β-catenin is a proto-oncogene and activating β-catenin mutations are relevant in the genesis of colorectal, hepatocellular and other common cancers. Different functions of β-catenin as transcriptional co-activator or cell adhesion molecule are orchestrated by changes in concentration and phosphorylation as well as its ability to complex with proteins such as cadherins or transcription factors. Detailed quantitative and time-resolved analysis of β-catenin, based on the evaluation of the changes in the Wnt pathway, enable greater insights into health- and disease-related β-catenin function. The present paper describes a novel suspension bead array assay panel for β-catenin, which requires minimal amounts of sample and is able to relatively quantify total β-catenin, the extent of phosphorylation at multiple sites and the ratio of complexed and free β-catenin. This is the first study to combine three biochemical methods--sandwich immunoassay, co-immunoprecipitation, and protein-protein interaction assay--in one suspension bead assay panel. The assay was used to measure changes in the concentration of eight different β-catenin forms in HEK293 cells in a time-resolved manner. In contrast to the general consensus, our study demonstrates an increase in β-catenin phosphorylated at Ser-45 upon treatment of cells with rWnt3a or a GSK3 inhibition; we also link C-terminal phosphorylation of β-catenin on Ser-552 and Ser-675 with canonical Wnt signaling.

Development of a multiplex bead-based assay for detection of hepatitis C virus

Hepatitis C virus (HCV) infection is a major burden to public health worldwide, affecting approximately 3% of the human population. Although HCV detection is currently based on reliable tests, the field of medical diagnostics has a growing need for inexpensive, accurate, and quick high-throughput assays. By using the recombinant HCV antigens NS3, NS4, NS5, and Combined, we describe a new bead-based multiplex test capable of detecting HCV infection in human serum samples. The first analysis, made in a singleplex format, showed that each antigen coupled to an individual bead set presented high-level responses for anti-HCV-positive reference serum pools and lower-level responses for the HCV-negative pools. Our next approach was to determine the sensitivity and specificity of each antigen by testing 93 HCV-positive and 93 HCV-negative sera. When assayed in the singleplex format, the NS3, NS4, and NS5 antigens presented lower sensitivity values (50.5%, 51.6%, and 55.9%, respectively) than did the Combined antigen, which presented a sensitivity of 93.5%. All antigens presented 100% specificity. These antigens were then multiplexed in a 4-plex assay, which resulted in increased sensitivity and specificity values, performing with 100% sensitivity and 100% specificity. The positive and negative predictive values for the 4-plex assay were 100%. Although preliminary, this 4-plex assay showed robust results that, aligned with its small-sample-volume requirements and also its cost- and time-effectiveness, make it a reasonable alternative to tests currently used for HCV screening of potentially infected individuals.

Measurement and illustration of immune interaction after stem cell transplantation

A variety of stem cells, including embryonic, mesenchymal, and hematopoietic stem cells, have been isolated to date, resulting in the current investigation of many therapeutic applications. These stem cells offer a high potential in cell replacement therapies or in the regeneration of organ damage. One current obstacle in using these stem cells in clinical applications are the unknown or unexplained mechanisms regarding the activation of immune responses as well as their given potential of immune activity, which can attack the host tissue. Similarly, the unknown immunological environment, which can benefit tumor growth, also restrains the rapid clinical implementation of stem cells. We have shown that several techniques for measurement or illustration of immune responses in a hematopoietic murine CD4(k/o) mice transplantation model might be beneficial to get new insight into in vivo behavior of transplanted stem cells. Subjected to the transplantation setups (allogeneic, syngeneic, or xenogenic transplantation) different immune responses (enhancement of CD4(+) T cells, cytokine activity) as well as different effects of the transplanted cells on the host organs (organ destruction, toxicity) are detectable. The methods used to describe such immune responses will be presented here.

Reduced choroidal neovascular membrane formation in cyclooxygenase-2 null mice

PURPOSE

To assess the degree of laser-induced choroidal neovascular membrane formation in wild-type (WT) and COX-2 null mice and to measure vascular endothelial growth factor (VEGF), interleukin (IL)-1β, and tumor necrosis factor (TNF)-α levels in the retina and choroid.

METHODS

Four laser burns were placed in each eye of WT and COX-2 null mice to induce choroidal neovascularization. Fluorescein angiography (FA) was performed at 14 days, and retinal pigment epithelium-choroid-sclera (choroidal) flat mounts were prepared. The retina and choroid were isolated from WT and COX-2 null mice at 24, 72, and 168 hours after laser photocoagulation and from unlasered eyes and were tested for VEGF, IL-1β, and TNF-α.

RESULTS

COX-2 null mice demonstrated 58% (P = 0.001) and 48% (P = 0.001) reductions in CNV formation on FA and choroidal flat mounts, respectively, compared with WT mice. For unlasered mice, mean VEGF concentrations in the retina and choroid were 1.2 ± 0.42 pg/mg protein for WT but only 0.42 ± 0.2 pg/mg protein for COX-2 null mice (P < 0.05). After laser photocoagulation, WT mice showed significantly greater VEGF and IL-β expression in the retina and choroid by 168 hours (P < 0.05) and 72 hours (P < 0.05), respectively, compared with COX-2 null mice.

CONCLUSIONS

COX-2 null mice exhibited significantly less choroidal neovascular membrane formation associated with reduced expression of VEGF. The results of this study suggest that COX-2 modulates VEGF expression in CNV and implicates a potential therapeutic role for nonsteroidal anti-inflammatory drugs.

Proteoglycans regulate the chemotaxis of dendritic cells derived from human peripheral blood monocytes

Dendritic cells (DCs) are a type of antigen-presenting cell which play an essential role in the immune system. The transition from immature DC (iDCs) to mature DCs (mDCs) requires appropriate maturation stimuli, such as pro-inflammatory cytokines or pathogen-derived components. Proteoglycans (PGs), which are composed of core proteins and the glycosaminoglycans that bind to them, are one of the main components of the extracellular matrix around pathogens such as bacteria. This study investigated the effects of PG extracted from the nasal septum cartilage of whale (W-PG) on the maturation of DCs derived from human peripheral blood monocytes. iDCs were prepared from human monocytes using granulocyte-macrophage colony-stimulating factor (GM-CSF) and interleukin-4 (IL-4). The iDCs were stimulated by W-PG alone. In another type of experiment, the iDCs were stimulated by MIX (tumor necrosis factor-alpha (TNF-alpha), IL-1beta, IL-6 and prostaglandin E(2) (PGE(2))) or a combination of MIX plus W-PG. The stimulation of W-PG alone did not induce the phenotypic maturation from iDCs. However, W-PG promoted the up-regulation of chemokine receptor CCR7-surface expression and the chemotactic responsiveness to CCR7 ligand macrophage inflammatory protein-3beta on MIX-stimulated mDCs although W-PG did not influence matrix metalloproteinase-9 activity which is an important factor in DC migration through the extracellular matrix. The findings that W-PG can selectively regulate the chemotactic activity of DCs in vitro under inflammatory conditions therefore indicate that the interaction of PGs with immune cells including DCs plays an important role in the immune response under the milieu of innate immunity.

Flow cytometry: an introduction

A flow cytometer is an instrument that illuminates cells (or other particles) as they flow individually in front of a light source and then detects and correlates the signals from those cells that result from the illumination. In this chapter, each of the aspects of that definition will be described: the characteristics of cells suitable for flow cytometry, methods to illuminate cells, the use of fluidics to guide the cells individually past the illuminating beam, the types of signals emitted by the cells and the detection of those signals, the conversion of light signals to digital data, and the use of computers to correlate and analyze the data after they are stored in a data file. The final section of the chapter will discuss the use of a flow cytometer to sort cells. This chapter can be read as a brief, self-contained survey. It can also be read as a gateway with signposts into the field. Other chapters in this book will provide more details, more references, and even an intriguing view of the future of cytometry.

An approach to multiplexing an immunosorbent assay with antibody-oligonucleotide conjugates

Early detection of cancer biomarkers provides clinically valuable information. While the conventional enzyme-linked immunosorbent assay (ELISA) has been routinely used for individual cancer markers, methods for simultaneous determination of multiple markers within a single sample are still in demand. Here, we present a novel oligonucleotide-linked immunosorbent assay (OLISA) with a multiplexing capability on the same microwell plate-based system as in ELISA. Employing a DNA oligonucleotide that is covalently conjugated to the detection antibody and a complementary RNA oligonucleotide which is appended with a fluorophore and a quencher, degradation of the RNA in the DNA-RNA duplex by RNase H is exploited for fluorescent signal generation. Iterative cycles of DNA-RNA duplexation and subsequent degradation of the RNA in the duplex by RNase H further lead to amplification of the detection signal in OLISA. Moreover, the use of antibody-oligonucleotide conjugates enables multiplexing of OLISA, which is successfully demonstrated by tethering DNA molecules to detection antibodies and by performing assays for three common cancer markers including α-fetoprotein, prostate-specific antigen, and carcinoembryonic antigen. With the simple procedure and reliable detection performance, the developed multiplex OLISA has a wide potential for use in analysis of a panel of biomarkers in clinical diagnostics.

DNA suspension arrays: silencing discrete artifacts for high-sensitivity applications

Detection of low frequency single nucleotide polymorphisms (SNPs) has important implications in early screening for tumorgenesis, genetic disorders and pathogen drug resistance. Nucleic acid arrays are a powerful tool for genome-scale SNP analysis, but detection of low-frequency SNPs in a mixed population on an array is problematic. We demonstrate a model assay for HIV-1 drug resistance mutations, wherein ligase discrimination products are collected on a suspension array. In developing this system, we discovered that signal from multiple polymorphisms was obscured by two discrete hybridization artifacts. Specifically: 1) tethering of unligated probes on the template DNA elicited false signal and 2) unpredictable probe secondary structures impaired probe capture and suppressed legitimate signal from the array. Two sets of oligonucleotides were used to disrupt these structures; one to displace unligated reporter labels from the bead-bound species and another to occupy sequences which interfered with array hybridization. This artifact silencing system resulted in a mean 21-fold increased sensitivity for 29 minority variants of 17 codons in our model assay for mutations most commonly associated with HIV-1 drug resistance. Furthermore, since the artifacts we characterized are not unique to our system, their specific inhibition might improve the quality of data from solid-state microarrays as well as from the growing number of multiple analyte suspension arrays relying on sequence-specific nucleic acid target capture.

Utilization of microparticles in next-generation assays for microflow cytometers

Micron-sized particles have primarily been used in microfabricated flow cytometers for calibration purposes and proof-of-concept experiments. With increasing frequency, microparticles are serving as a platform for assays measured in these small analytical devices. Light scattering has been used to measure the agglomeration of antibody-coated particles in the presence of an antigen. Impedance detection is another technology being integrated into microflow cytometers for microparticle-based assays. Fluorescence is the most popular detection method in flow cytometry, enabling highly sensitive multiplexed assays. Finally, magnetic particles have also been used to measure antigen levels using a magnetophoretic micro-device. We review the progress of microparticle-based assays in microflow cytometry in terms of the advantages and limitations of each approach.

Validation of multiplex microbead immunoassay for simultaneous serodetection of multiple infectious agents in laboratory mouse

Multiplex methodologies enable simultaneous detection of antibodies against several infectious agents allowing sample conservation, cost effectiveness, and amenability to high-throughput/automation. We have previously described a multiplex microbead immunoassay for serodetection of ten, high-priority mouse infectious pathogens. Here, we present a validation of this multiplex diagnostic system using approximately four hundred serum samples from different groups of mice. Computer assisted multivariate analysis of the resulting high volume data (8000 data points) was performed. This computational approach enabled presentation of data in a variety of easily interpretable formats (e.g., correlation tables and heat maps). Importantly, this computer aided approach was instrumental for the evaluation of assay accuracy, sensitivity, specificity, and robustness during the study. Crucial pieces of information were obtained to make timely adjustments for assay refinement. This progressive approach to developing an implementation-ready clinical assay, facilitated by computational analysis, produced a highly efficient, accurate and dependable serodiagnostics system. This system has effectively replaced the current state-of-the-art methodology (ELISA) used in mouse colony health management at the University of California and the Jackson Laboratory. A pathway to develop multiplex serology tests for infectious disease diagnosis described here serves as a model for multiplex immunoassay design, clinical validation, refinement and implementation.

Development of a fluorescent microsphere immunoassay for cystatin B (CSTB) in serum of patients with hepatocellular carcinoma

BACKGROUND

Serum cystatin B (CSTB) concentrations have been reported to be increased in patients with hepatocellular carcinoma compared to concentrations seen in normal subjects. In this study, we developed a "fluorescent microsphere immunoassay" (FMI) capable of specifically detecting CSTB in serum.

METHODS

The FMI used a microparticle conjugated polyclonal antibody to CSTB and biotinylated monoclonal antibody as capture protein and probe protein, respectively. The results were obtained using the Bio-Plex(200) system.

RESULTS

The dose-response relationship between CSTB and fluorescent intensity showed linearity in the range 0-1000 pg/mL and 7 pg/mL, sensitivity lower than 11.2 pg/mL. This result revealed that the FMI system was more sensitive than enzyme-linked immunoassay (ELISA). Additionally, the FMI system used smaller sample volumes compared to ELISA.

CONCLUSIONS

We measured CSTB with both the FMI and an ELISA procedure and compared the two methods. The CSTB concentrations in serum specimens as measured with the FMI assay system were similar to those measured with ELISA. Thus, the new FMI using the Bio-Plex system may be useful for detection of CSTB in human serum.

Characterization and development of a Luminex®-based assay for the detection of human IL-23

Background: IL-23 is a cytokine produced by dendritic cells, T-cells and macrophages that plays a critical regulatory role in the inflammatory and autoimmune responses. We describe the development and preclinical validation of a highly sensitive Luminex® assay specific to IL-23 that is suitable for its measurement in support of early-phase clinical trials. Results: Intra-assay precision for the BioSource™ ELISA was under 12.3%, and under 5.2% for the eBioscience® ELISA. In comparison, the Luminex assays provided an intra-assay precision under 6.2%. The measured inter-assay precision was less than 15.6% for the BioSource ELISA, under 33% for the eBioscience and less than 10% for the Luminex assays. Conclusions: The Luminex method described provides a way to measure IL-23 in clinical samples either as a single biomarker or as a panel of biomarkers. The assay should prove useful to scientists and clinicians investigating the biology of IL-23 and to those needing to monitor changes in IL-23 as part of a clinical study.

Multiplex cytokine analysis reveals elevated concentration of interleukin-8 in glaucomatous aqueous humor

PURPOSE

To test the hypothesis that immune activation occurs in glaucoma by comparing concentrations of multiple cytokines in aqueous humor (AH) from patients with primary open angle glaucoma (POAG) and from cataract patients without glaucoma as controls.

METHODS

Cytokine concentrations in AH obtained during surgery were measured using microparticle-based immunoassays. Localized expression of IL-8 protein was investigated by immunohistochemistry of human eyes.

RESULTS

Eight cytokines (IL-1β, IL-2, IL-4, IL-5, IL-10, IL-12, IFN-γ, and TNF-α) were below the limits of detection, and two cytokines (IL-18 and IL-15) were detected at low levels or in only a few patients. Although IL-6 was detected in 26 of 30 control patients (median, 2.7 pg/mL) and in 23 of 29 POAG patients (median, 1.6 pg/mL), the difference was not statistically significant. IL-8 was detected in 28 of 30 control patients (median, 1.8 pg/mL) and in all 29 POAG patients (median, 4.9 pg/mL). The higher IL-8 concentration in the AH of POAG patients was statistically significant (P < 0.001). In pairs of eyes from patients with asymmetric glaucomatous optic nerve damage, IL-8 concentration was higher in the AH of the more severely affected eye (P < 0.05). Patients with severe visual field defects had higher IL-8 concentrations in the AH than did patients with mild visual field defects. IL-8 protein expression was found in human retina and optic nerve.

CONCLUSIONS

Concentration of the inflammatory cytokine IL-8 is significantly elevated in the AH of POAG patients, supporting the hypothesis that immune activation occurs in glaucoma.

Kidney injury molecule-1 outperforms traditional biomarkers of kidney injury in preclinical biomarker qualification studies

Kidney toxicity accounts both for the failure of many drug candidates as well as considerable patient morbidity. Whereas histopathology remains the gold standard for nephrotoxicity in animal systems, serum creatinine (SCr) and blood urea nitrogen (BUN) are the primary options for monitoring kidney dysfunction in humans. The transmembrane tubular protein kidney injury molecule-1 (Kim-1) was previously reported to be markedly induced in response to renal injury. Owing to the poor sensitivity and specificity of SCr and BUN, we used rat toxicology studies to compare the diagnostic performance of urinary Kim-1 to BUN, SCr and urinary N-acetyl-beta-D-glucosaminidase (NAG) as predictors of kidney tubular damage scored by histopathology. Kim-1 outperforms SCr, BUN and urinary NAG in multiple rat models of kidney injury. Urinary Kim-1 measurements may facilitate sensitive, specific and accurate prediction of human nephrotoxicity in preclinical drug screens. This should enable early identification and elimination of compounds that are potentially nephrotoxic.

Multi analyte profiling and variability of inflammatory markers in blood and induced sputum in patients with stable COPD

BACKGROUND

We analyzed serial concentrations of multiple inflammatory mediators from serum and induced sputum obtained from patients with stable COPD and controls. The objective was to determine which proteins could be used as reliable biomarkers to assess COPD disease state and severity.

METHODS

Forty-two subjects; 21 with stable COPD and 21 controls, were studied every 2 weeks over a 6-week period. Serum and induced sputum were obtained at each of 3 visits and concentrations of 19 serum and 22 sputum proteins were serially assessed using multiplex immunoassays. We used linear mixed effects models to test the distribution of proteins for an association with COPD and disease severity. Measures of within- and between-subject coefficients of variation were calculated for each of the proteins to assess reliability of measurement.

RESULTS

There was significant variability in concentrations of all inflammatory proteins over time, and variability was greater for sputum proteins (median intra-subject coefficient of variation 0.58) compared to proteins measured in serum (median intra-subject coefficient of variation 0.32, P = 0.03). Of 19 serum proteins and 22 sputum proteins tested, only serum CRP, myeloperoxidase and VEGF and sputum IL-6, IL-8, TIMP-1, and VEGF showed acceptable intra and inter-patient reliability and were significantly associated with COPD, the severity of lung function impairment, and dyspnea.

CONCLUSIONS

Levels of many serum and sputum biomarkers cannot be reliably ascertained based on single measurements. Multiple measurements over time can give a more reliable and precise estimate of the inflammatory burden in clinically stable COPD patients.

Laparotomy attenuates lipopolysaccharide-induced gastric bleeding in the rat

Lipopolysaccharide (LPS) increases systemic inflammation and causes duodenogastric reflux of bile and gastric bleeding. Laparotomy prevents gastric injury from the luminal irritant bile, but its effects on LPS-induced gastric injury are unknown. We hypothesized that laparotomy would diminish inflammation and attenuate gastric bleeding caused by LPS. In the rat, laparotomy, done either before or after administration of LPS, attenuated LPS-induced bile reflux, gastric bleeding, and cyclooxygenase-2, but not inducible nitric oxide synthase, expression when compared to controls given LPS. Laparotomy also blunted LPS-induced changes in serum cytokine production. These data suggest that laparotomy has gastroprotective effects by preventing LPS-induced bile reflux and gastric bleeding and by a mechanism mediated, at least in part by cyclooxygenase-2.

1950 MHz IMT-2000 field does not activate microglial cells in vitro

Given the widespread use of the cellular phone today, investigation of potential biological effects of radiofrequency (RF) fields has become increasingly important. In particular, much research has been conducted on RF effects on brain function. To examine any biological effects on the central nervous system (CNS) induced by 1950 MHz modulation signals, which are controlled by the International Mobile Telecommunication-2000 (IMT-2000) cellular system, we investigated the effect of RF fields on microglial cells in the brain. We assessed functional changes in microglial cells by examining changes in immune reaction-related molecule expression and cytokine production after exposure to a 1950 MHz Wideband Code Division Multiple Access (W-CDMA) RF field, at specific absorption rates (SARs) of 0.2, 0.8, and 2.0 W/kg. Primary microglial cell cultures prepared from neonatal rats were subjected to an RF or sham field for 2 h. Assay samples obtained 24 and 72 h after exposure were processed in a blind manner. Results showed that the percentage of cells positive for major histocompatibility complex (MHC) class II, which is the most common marker for activated microglial cells, was similar between cells exposed to W-CDMA radiation and sham-exposed controls. No statistically significant differences were observed between any of the RF field exposure groups and the sham-exposed controls in percentage of MHC class II positive cells. Further, no remarkable differences in the production of tumor necrosis factor-alpha (TNF-alpha), interleukin-1beta (IL-1beta), and interleukin-6 (IL-6) were observed between the test groups exposed to W-CDMA signal and the sham-exposed negative controls. These findings suggest that exposure to RF fields up to 2 W/kg does not activate microglial cells in vitro.

Emerging affinity-based techniques in proteomics

Proteomes of interest, such as the human proteome, have such complexity that no single technique is adequate for the complete analysis of the constituents. Depending on the goal (e.g., identification of a novel protein vs measurement of the level of a known protein), the tools required can vary significantly. While existing methods provide valuable information, their limitations drive the development of complementary, innovative methods to achieve greater breadth of coverage, dynamic range or specificity of analysis. We will discuss affinity-based methods and their applications, focusing on their unique advantages. In addition, we will describe emerging methods with potential value to proteomics, as well as the challenges that remain for proteomic studies.

Regional gene expression of LOX-1, VCAM-1, and ICAM-1 in aorta of HIV-1 transgenic rats

Background

Increased prevalence of atherosclerotic cardiovascular disease in HIV-infected patients has been observed. The cause of this accelerated atherosclerosis is a matter of controversy. As clinical studies are complicated by a multiplicity of risk-factors and a low incidence of hard endpoints, studies in animal models could be attractive alternatives.

Methodology/Principal Findings

We evaluated gene expression of lectin-like oxidized-low-density-lipoprotein receptor-1 (LOX-1), vascular cell adhesion molecule-1 (VCAM-1), and intercellular adhesion molecule-1 (ICAM-1) in HIV-1 transgenic (HIV-1Tg) rats; these genes are all thought to play important roles in early atherogenesis. Furthermore, the plasma level of sICAM-1 was measured. We found that gene expressions of LOX-1 and VCAM-1 were higher in the aortic arch of HIV-1Tg rats compared to controls. Also, the level of sICAM-1 was elevated in the HIV-1Tg rats compared to controls, but the ICAM-1 gene expression profile did not show any differences between the groups.

Conclusions/Significance

HIV-1Tg rats have gene expression patterns indicating endothelial dysfunction and accelerated atherosclerosis in aorta, suggesting that HIV-infection per se may cause atherosclerosis. This transgenic rat model may be a very promising model for further studies of the pathophysiology behind HIV-associated cardiovascular disease.

Determinants of the relationship between cytokine production in pregnant women and their infants

Exposure to environmental factors during fetal life and infancy is thought to play an important role in the early development of innate and adaptive immunity. The immunological relationship between mother and infant and the effect that environmental exposures have during pregnancy and early childhood have not been studied extensively. Here the production of cytokines was measured in 146 pairs of mothers and their 2- month-old infants. The effect of place of residence, socio-economic variables, parasitic infections as well as maternal and child characteristics on measured cytokine production was determined. Mothers producing high levels of IL-10, IFN-gamma and IL-5 were more likely to have infants who also produced high levels of these cytokines either spontaneously (OR 2.6(95%CI 1.2-5.4), OR 2.9(CI 1.3-6.6), OR 11.2(CI 4.6-27.2), respectively) or in response to PHA (IL-10: OR 3.0(CI 1.4-6.6), IFN-gamma: OR 2.0(CI 1.0-4.2), respectively) even after adjustment for potential confounding variables. This was not the case for TNF-alpha. In response to LPS, place of residence was a strong determinant of infant IL-10 (OR 0.2(CI 0.1-0.9)) and TNF-alpha (OR 0.3(CI 0.1-0.9)) production. Maternal protozoan infections was independently associated with reduced infant IL10 in response to PHA and to LPS as well as reduced TNF-alpha and IFN-gamma in response to PHA. These results indicate strong relationship between maternal and infant's cellular immune responses even after taking into account many environmental influences that could affect infant's response directly or indirectly through uterine microenvironment. However, place of residence and intestinal infections may still directly affect the immune responses of the infant. Taken together, the study provides evidence for imprinted cytokine responses of an infant which may have implications for their reaction to incoming antigens, warranting further investigation into the role that genetics or epigenetics play in shaping the cytokine response by an infant to self or external antigens.

Oleanolic Acid, a plant triterpenoid, significantly improves survival and function of islet allograft

BACKGROUND.: Oleanolic acid (OA) is a ubiquitous triterpenoid, with potent antioxidant and anti-inflammatory properties. Here, we tested whether these combined properties of OA can prevent nonimmunologic primary nonfunctioning and immunologic phenomena ascribed to graft rejection hence prolong islet allograft survival. METHODS.: Islet transplants were performed under kidney capsule of streptozotocin-induced diabetic C57BL/6 mice with BALB/c islets. Recipients were treated with 0.5 mg/day of OA intraperitoneally, and serum samples were collected once in 2 days and used for luminex, ELISA, and donor-specific antibody screening. Transplanted mice were killed at different time intervals to obtain splenocytes and kidney samples for ELISPOT, mixed leukocyte reaction, and immunohistochemical studies. RESULTS.: After transplantation, the decrement of blood glucose was significantly faster in mice receiving OA less than 2+/-1 days compared with untreated (4+/-2 days). OA prolonged survival of transplanted islets up to 23+/-3 days and reversed diabetes even with 250 islets. Treatment group showed increased serum interleukin (IL)-10 (twofold) and decreased inducible protein-10 and IL-4 (threefold) in luminex. Significantly reduced frequency of interferon-gamma (4.5-fold), IL-4 (3.5-fold), IL-2 (2.3-fold), and IL-17 (fourfold) producing T-cell populations were found in ELISPOT. OA-treated grafts had significant reduced and delayed infiltration of CD4+ and CD8+ T cells. OA also delayed donor-specific antibody generation up to 19 days after transplantation. Combined treatment with cyclosporine A, OA further prolonged the islet allograft survival to 34+/-3 days. CONCLUSIONS.: In conclusion, OA is an attractive, dietary nontoxic plant triterpenoid, which suppresses the production of proinflammatory cytokines and delays graft-specific immune responses to prolong islet allograft survival.

Exaggerated inflammatory response of primary human myeloid dendritic cells to lipopolysaccharide in patients with inflammatory bowel disease

Inflammatory bowel disease (IBD) results from a breakdown of tolerance towards the indigenous flora in genetically susceptible hosts. Failure of dendritic cells (DC) to interpret molecular microbial patterns appropriately when directing innate and adaptive immune responses is conceivable. Primary (conventional, non-monocyte generated) CD1c(+)CD11c(+)CD14(-)CD16(-)CD19(-) myeloid blood or mucosal dendritic cells (mDC) from 76 patients with Crohn's disease (CD) or ulcerative colitis (UC) in remission, during flare-ups (FU) and 76 healthy or non-IBD controls were analysed by fluorescence activated cell sorter (FACS) flow cytometry and real-time polymerase chain reaction. Cytokine secretion of freshly isolated, cultured and lipopolysaccharide (LPS)-stimulated highly purified mDC (purity >95%) was assessed using cytometric bead arrays (CBA). More cultured and stimulated circulating mDC express CD40 in IBD patients. Stimulated circulating mDC from IBD patients secrete significantly more tumour necrosis factor (TNF)-alpha and interleukin (IL)-8. Toll-like receptor (TLR)-4 expression by mDC was higher in remission and increased significantly in flaring UC and CD patients compared with remission (P < 0.05) and controls (P < 0.001). Fluorochrome-labelled LPS uptake by mDC was evaluated at different time-points over 24 h by measuring mean fluorescence intensity (MFI). Circulating mDC from IBD patients take up more LPS and the uptake begins earlier compared with controls (P < 0.05 in CD-FU and UC-FU at 24 h). The frequency of mucosal mDC (P < 0.05) and the number of CD40 expressing mucosal mDC is significantly greater in UC and CD compared with non-IBD controls (P < 0.001 versus P < 0.01, respectively). Our data suggest an aberrant LPS response of mDC in IBD patients, resulting in an inflammatory phenotype and possibly intestinal homing in acute flares.

Multiplexed microbead immunoassays by flow cytometry for molecular profiling: Basic concepts and proteomics applications

Flow cytometry was originally established as an automated method for measuring optical or fluorescence characteristics of cells or particles in suspension. With the enormous increase in development of reliable electronics, lasers, micro-fluidics, as well as many advances in immunology and other fields, flow cytometers have become user-friendlier, less-expensive instruments with an increasing importance for both basic research and clinical applications. Conventional uses of flow cytometry include immunophenotyping of blood cells and the analysis of the cell cycle. Importantly, methods for labeling microbeads with unique combinations of fluorescent spectral signatures have made multiplex analysis of soluble analytes (i.e. the ability to detect multiple targets in a single test sample) feasible by flow cytometry. The result is a rapid, high-throughput, sensitive, and reproducible detection technology for a wide range of biomedical applications requiring detection of proteins (in cells and biofluids) and nucleic acids. Thus, novel methods of flow cytometry are becoming important for diagnostic purposes (e.g. identifying multiple clinical biomarkers for a wide range of diseases) as well as for developing novel therapies (e.g. elucidating drug mechanisms and potential toxicities). In addition, flow cytometry for multiplex analysis, coupled with automated sample handling devices, has the potential to significantly enhance proteomics research, particularly analysis of post-translational modifications of proteins, on a large scale. Inherently, flow cytometry methods are strongly rooted in the laws of the physics of optics, fluidics, and electromagnetism. This review article describes principles and early sources of flow cytometry, provides an introduction to the multiplex microbead technology, and discusses its applications and advantages in comparison to other methods. Anticipated future directions, particularly for translational research in medicine, are also discussed.

Pan-DR-binding Hsp60 self epitopes induce an interleukin-10-mediated immune response in rheumatoid arthritis

OBJECTIVE

Human Hsp60 is expressed in the joints of patients with rheumatoid arthritis (RA) and can elicit a regulatory T cell response in the peripheral blood and synovial fluid. However, Hsp60 can also trigger strong proinflammatory pathways. Thus, to understand the nature of these Hsp60-directed responses in RA, it is necessary to study such responses at the molecular, epitope-specific level. This study was undertaken to characterize the disease specificity and function of pan-DR-binding Hsp60-derived epitopes as possible modulators of autoimmune inflammation in RA.

METHODS

Lymphocyte proliferation assays (using (3)H-thymidine incorporation and carboxyfluorescein diacetate succinimidyl ester [CFSE] staining) and measurement of cytokine production (using multiplex immunoassay and intracellular staining) were performed after in vitro activation of peripheral blood mononuclear cells from patients with RA, compared with healthy controls.

RESULTS

A disease (RA)-specific immune recognition, characterized by T cell proliferation as well as increased production of tumor necrosis factor alpha (TNFalpha), interleukin-1beta (IL-1beta), and IL-10, was found for 3 of the 8 selected peptides in patients with RA as compared with healthy controls (P < 0.05). Intracellular cytokine staining and CFSE labeling showed that CD4+ T cells were the subset primarily responsible for both the T cell proliferation and the cytokine production in RA. Interestingly, the human peptides had a remarkably different phenotype, with a 5-10-fold higher IL-10:TNFalpha ratio, compared with that of the microbial peptides.

CONCLUSION

These results suggest a disease-specific immune-modulatory role of epitope-specific T cells in the inflammatory processes of RA. Therefore, these pan-DR-binding epitopes could be used as a tool to study the autoreactive T cell response in RA and might be suitable candidates for use in immunotherapy.

A central role for transcription factor C/EBP-beta in regulating CD1d gene expression in human keratinocytes

CD1d is a nonclassical Ag-presenting molecule that presents glycolipid Ags to NKT cells that are involved in immune defense and tumor rejection. It also plays a role in immunoregulatory functions in the epidermis. The mechanisms controlling the expression of CD1d are not well understood. Therefore, we cloned the CD1d gene promoter and characterized its activities in primary human keratinocytes and other cell lines of epithelial origin. We found that a CCAAT box in the CD1d promoter is required for its expression in keratinocytes. We show here that transcription factor C/EBP-beta binds to the CCAAT box in the CD1d promoter in vitro and in vivo. Consistent with these observations, deletion of the gene encoding for C/EBP-beta caused a loss of CD1d expression. The in vivo regulation of CD1d has significant implications for the pathologic mechanisms of certain immunologic skin diseases in which NKT cells play a role, such as allergic contact dermatitis and psoriasis. Together, these data show a central role for C/EBP-beta in regulating CD1d transcription.

Development of rapid detection and genetic characterization of salmonella in poultry breeder feeds

Salmonella is a leading cause of foodborne illness in the United States, with poultry and poultry products being a primary source of infection to humans. Poultry may carry some Salmonella serovars without any signs or symptoms of disease and without causing any adverse effects to the health of the bird. Salmonella may be introduced to a flock by multiple environmental sources, but poultry feed is suspected to be a leading source. Detecting Salmonella in feed can be challenging because low levels of the bacteria may not be recovered using traditional culturing techniques. Numerous detection methodologies have been examined over the years for quantifying Salmonella in feeds and many have proven to be effective for Salmonella isolation and detection in a variety of feeds. However, given the potential need for increased detection sensitivity, molecular detection technologies may the best candidate for developing rapid sensitive methods for identifying small numbers of Salmonella in the background of large volumes of feed. Several studies have been done using polymerase chain reaction (PCR) assays and commercial kits to detect Salmonella spp. in a wide variety of feed sources. In addition, DNA array technology has recently been utilized to track the dissemination of a specific Salmonella serotype in feed mills. This review will discuss the processing of feeds and potential points in the process that may introduce Salmonella contamination to the feed. Detection methods currently used and the need for advances in these methods also will be discussed. Finally, implementation of rapid detection for optimizing control methods to prevent and remove any Salmonella contamination of feeds will be considered.

A rapid urine test for early detection of kidney injury

Kidney injury molecule-1 (Kim-1) has been qualified by the Food and Drug Administration and European Medicines Agency as a highly sensitive and specific urinary biomarker to monitor drug-induced kidney injury in preclinical studies and on a case-by-case basis in clinical trials. Here we report the development and evaluation of a rapid direct immunochromatographic lateral flow 15-min assay for detection of urinary Kim-1 (rat) or KIM-1 (human). The urinary Kim-1 band intensity using the rat Kim-1 dipstick significantly correlated with levels of Kim-1 as measured by a microbead-based assay, histopathological damage, and immunohistochemical assessment of renal Kim-1 in a dose- and time-dependent manner. Kim-1 was detected following kidney injury induced in rats by cadmium, gentamicin, or bilateral renal ischemia/reperfusion. In humans, the urinary KIM-1 band intensity was significantly greater in urine from patients with acute kidney injury than in urine from healthy volunteers. The KIM-1 dipstick also enabled temporal evaluation of kidney injury and recovery in two patients who developed postoperative acute kidney injury following cytoreductive surgery for malignant mesothelioma with intraoperative local cisplatin administration. We hope that future, more extensive studies will confirm the utility of these results, which show that the Kim-1/KIM-1 dipsticks can provide a sensitive and accurate detection of Kim-1/KIM-1, thereby providing a rapid diagnostic assay for kidney damage and facilitating the rapid and early detection of kidney injury in preclinical and clinical studies.

In vitro end points for the assessment of cellular immune response-modulating drugs

BACKGROUND

The concept of immunotoxicology and the development of a battery of immune-function assays to screen potential immunotoxic compounds have been increasingly used in the past. Immunotoxic outcome generally seems appropriate to evaluate the risk in drug development. Improving this approach is possible, by using methods now available, to study the effect of a chemical compound on the immune system.

OBJECTIVE

The goal of this review is to provide an overview of the current and recent methodologies for testing the immunological effect and immunotoxic risks in drug candidates.

METHODS

The methodological details here discussed include a synthetic description of the immunocompetent cells in cell-mediated immunity and the choice of the most appropriate assay (bioassays, immunoassays, molecular biology techniques, flow cytometry).

CONCLUSION

This review offers an assessment of in vitro models to study the toxic impact of (bio)pharmaceuticals on cellular immune system and aid drug scientists in understanding the significance and the methods to approach immunotoxicology.

Inflammatory cytokine levels in chronic venous insufficiency ulcer tissue before and after compression therapy

OBJECTIVE

Elevated inflammatory cytokine levels have been implicated in the pathogenesis of non-healing chronic venous insufficiency (CVI) ulcers. The goal of this study was to determine the protein levels of a wide range of inflammatory cytokines in untreated CVI ulcer tissue before and after 4 weeks of high-strength compression therapy. These levels were compared to cytokines present in healthy tissue.

METHODS

Thirty limbs with untreated CVI and leg ulceration received therapy for 4 weeks with sustained high-compression bandaging at an ambulatory wound center. Biopsies were obtained from healthy and ulcerated tissue before and after therapy. A multiplexed protein assay was used to measure multiple cytokines in a single sample. Patients were designated as rapid or delayed healers based on ulcer surface area change.

RESULTS

The majority of pro-inflammatory cytokine protein levels were elevated in ulcer tissue compared to healthy tissue, and compression therapy significantly reduced these cytokines. TGF-beta1 was upregulated in ulcer tissue following compression therapy. Rapid healing ulcers had significantly higher levels of IL-1alpha, IL-1beta, IFN-gamma, IL-12p40, and granulocyte macrophage colony stimulating factor (GM-CSF) before compression therapy, and IL-1 Ra after therapy. IFN-gamma levels significantly decreased following therapy in the rapidly healing patients.

CONCLUSION

CVI ulcer healing is associated with a pro-inflammatory environment prior to treatment that reflects metabolically active peri-wound tissue that has the potential to heal. Treatment with compression therapy results in healing that is coupled with reduced pro-inflammatory cytokine levels and higher levels of the anti-inflammatory cytokine IL-1 Ra.

Simple fabrication of a smart microarray of polystyrene microbeads for immunoassay

We describe a simple method to fabricate an array of polystyrene microbeads (PS microbeads) conjugated with an elastin-like polypeptide (ELP) on a glass surface using a removable polymer template (RPT). A thin layer of adhesive was spun-cast on glass and cured by UV radiation. Micropatterns of an RPT were then transferred onto the surface by microcontact printing. The adhesion of PS microbeads on the surface depended on the adhesion performance of the adhesive layer, which could be adjusted by irradiation time. An array of PS microbeads conjugated with ELP was used for a smart immunoassay of prostate-specific antigen (PSA), a cancer marker. By controlling the phase transition of ELP molecules, PSA molecules were selectively adhered or released from the bead surface. The selective and reversible binding of PSA molecules on the bead surface was characterized with fluorescence microscopy.

Fasting exacerbates and feeding diminishes LPS-induced liver injury in the rat

INTRODUCTION

Enteral nutrition improves clinical outcomes. The effects of feeding on LPS induced liver injury are unknown. We hypothesized that feeding would attenuate liver injury from LPS.

METHODS

Fasted or fed rats were given LPS (20 mg/kg i.p.) or saline for 5 h and sacrificed. Serum aminotransferases and cytokines (immunoassay) were measured. Oxidative stress protein (iNOS, COX2, and HO1) assessments (Western immunoblot) were also obtained.

RESULTS

In fasted rats, LPS significantly increased serum aminotransferase levels, enhanced hepatic COX2, iNOS, and HO1 immunoreactivity, and increased serum cytokine levels when compared to controls. While feeding diminished liver enzymes, attenuated expression of COX2 and iNOS, and blunted production of pro-inflammatory cytokines, it did not modulate LPS-induced expression of the anti-inflammatory markers HO1 and IL-10.

CONCLUSION

These data suggest that feeding decreases liver injury by attenuating expression of pro-inflammatory mediators while maintaining expression of anti-inflammatory mediators, both systemically and locally.

Transient cytokine-induced liver injury following administration of the humanized anti-CD3 antibody visilizumab (HuM291) in Crohn's disease

OBJECTIVES

Monoclonal antibodies to CD3 and CD4 T-cell receptors are evolving for Crohn's disease (CD) and ulcerative colitis. Their administration is often associated with a cytokine release syndrome (CRS).

METHODS

We evaluated data from two prospective clinical trials (NCT00267709 and NCT00267722) of visilizumab (HuM291), a novel humanized anti-CD3 antibody, in 34 patients with CD who received 10 microg/kg intravenously on 2 consecutive days. Serum hepatic tests including bilirubin, alkaline phosphatase (AP), gamma-glutamyltransferase (GGT), alanine aminotransferase (ALT) and aspartate aminotransferase (AST), visilizumab concentrations, and a panel of 16 cytokines were measured pre- and postadministration of visilizumab.

RESULTS

Patients experienced CRS symptoms at a median of 45 min postinfusion. The cytokine profile was characterized by interferon-inducible protein-10 (IP-10), interleukin-10 (IL-10), tumor necrosis factor-alpha (TNF-alpha), interferon-gamma, monocyte chemotactic protein 1 (MCP-1), interleukin-8 (IL-8), interleukin-6 (IL-6), interleukin-2 (IL-2), and interleukin 1 receptor antagonist (IL-1Ra), which were elevated between 6 (IL-1Ra) and 870 (IP-10) times their baseline concentrations. TNF-alpha and IL-2 peaked at the first day 1 h post infusion, whereas all others peaked at 6 h post infusion. Eighty-six percent of patients experienced an elevation above the upper limit of normal in hepatic enzymes (GGT 73%, AST 73%, ALT 64%, and AP 42% of patients), but not bilirubin, within 6 h postinfusion.

CONCLUSIONS

Transient elevation of hepatic enzymes occurred frequently in patients with CD treated with visilizumab and was associated with CRS. CD patients could be predisposed due to an aberrant expression of adhesion molecules in the liver that promotes CRS upon engagement of the T-cell receptor and may relate to extraintestinal disease manifestations such as primary sclerosing cholangitis.

SFMAC: a novel method for analyzing multiple parameters on lymphocytes with a single fluorophore in cell-microarray system

The analysis of single cells with multiple parameters in flow cytometry or microscopy requires suitable combinations of fluorophores and optical filters. The growing demands for the multiplex analysis of cells increase the requirements for developing new fluorophores and techniques. We have developed a novel method of analyzing a large number of cells with multiple parameters on a single-cell basis using a single fluorophore. Cells were arrayed onto a microwell array chip with an array of 45,000 microwells, which could capture single cells, stained with a phycoerythrin (PE)-conjugated antibody to a marker, and analyzed with a cell-scanner. After analysis, we photobleached the PE molecules by irradiating the sample with blue light. Because the fluorescence of PE was not recovered after the photobleaching and the analyzed cells remained in the same microwells on the chip, we could repeatedly stain and analyze the same cells with other markers using PE. We applied a method of analyzing lymphocytes from 100 microL of peripheral blood for cytokine secretion and expression of intracellular proteins as well as for multiple cell surface markers. This novel method enables us to analyze multiple markers with a single fluorophore using a simple apparatus. The method may expand the scope of cytometry.

Saccharomyces boulardii inhibits lipopolysaccharide-induced activation of human dendritic cells and T cell proliferation

Saccharomyces boulardii (Sb) is a probiotic yeast preparation that has demonstrated efficacy in inflammatory and infectious disorders of the gastrointestinal tract in controlled clinical trials. Although patients clearly benefit from treatment with Sb, little is known on how Sb unfolds its anti-inflammatory properties in humans. Dendritic cells (DC) balance tolerance and immunity and are involved critically in the control of T cell activation. Thus, they are believed to have a pivotal role in the initiation and perpetuation of chronic inflammatory disorders, not only in the gut. We therefore decided to investigate if Sb modulates DC function. Culture of primary (native, non-monocyte-derived) human myeloid CD1c+CD11c+CD123(-) DC (mDC) in the presence of Sb culture supernatant (active component molecular weight < 3 kDa, as evaluated by membrane partition chromatography) reduced significantly expression of the co-stimulatory molecules CD40 and CD80 (P < 0.01) and the DC mobilization marker CC-chemokine receptor CCR7 (CD197) (P < 0.001) induced by the prototypical microbial antigen lipopolysaccharide (LPS). Moreover, secretion of key proinflammatory cytokines such as tumour necrosis factor-alpha and interleukin (IL)-6 were notably reduced, while the secretion of anti-inflammatory IL-10 increased. Finally, Sb supernatant inhibited the proliferation of naive T cells in a mixed lymphocyte reaction with mDC. In summary, our data suggest that Sb may exhibit part of its anti-inflammatory potential through modulation of DC phenotype, function and migration by inhibition of their immune response to bacterial microbial surrogate antigens such as LPS.

Protein microarrays: effective tools for the study of inflammatory diseases

Inflammation is a defense reaction of an organism against harmful stimuli such as tissue injury or infectious agents. The relationship between the infecting microorganism and the immune, inflammatory, and coagulation responses of the host is intricately intertwined. Due to its complex nature, the molecular mechanisms of inflammation are not yet understood in detail and additional diagnostic tools are required to clarify further aspects. In recent years, protein microarray-based research has moved from being technology-based to application-oriented. Protein microarrays are perfect tools for studying inflammatory diseases. High-density protein arrays enable new classes of autoantibodies, which cause autoimmune diseases, to be discovered. Protein arrays consisting of miniaturized multiplexed sandwich immunoassays allow the simultaneous expression analysis of dozens of signaling molecules such as the cytokines and chemokines involved in the regulation of the immune system. The data enable statements to be made on the status of the disease and its progression as well as support for the clinicians in choosing patient-specific treatment. This chapter reviews the technology and the applications of protein microarrays in diagnosing and monitoring inflammatory diseases.

Validation and comparison of two multiplex technologies, Luminex and Mesoscale Discovery, for human cytokine profiling

Biomarker research has rapidly expanded over recent years aided by the progressive development of research tools, in particular the different multiplex technologies allowing simultaneous measurement of multiple analytes. It is foreseeable that such technology will have an integral role in clinical studies for establishing biomarker profiles of disease status, but validation of the tools is essential to confirm the reliability of their application. More comparable studies between multiplex platforms are required to enable users to determine which of these are best for a particular clinical study, as different platforms will have varying levels of performance for the validation parameters. Comparison of two multiplex platforms, the Luminex and the Mesoscale Discovery, has been performed to determine their performance for the validation parameters of sensitivity, precision and accuracy for the cytokines IL-2, IL-4, IL-8, IL-10, IL-12, IFNgamma and TNFalpha. When measuring high concentrations both platforms show good accuracy (within +/-25% recovery) with all cytokines except IL-12 for the MSD. At low concentrations, +/-25% recovery was seen with all cytokines except IL-2 and IL-8 for the Luminex and IL-2 and IL-12 for the MSD. Although quantitative differences are found, relative differences are comparable, and consequently both platforms have been shown to be suitable for analyzing trends in multiple cytokine profiles, with the Luminex having better precision and the Mesoscale Discovery having greater sensitivity.