Quantity and Quality of Basophil RNA Depend on the RNA Extraction Technique.

Basophils have been suggested to express low quantities of RNA, challenging the study of gene expression within these cells. However, the purification technique employed might have an impact on the quantity and quality of RNA purified from basophils. This chapter describes a method which gives an optimal RNA output using a TRIzol-based method in contrast to a commercial kit.

Measuring Histamine and Cytokine Release from Basophils and Mast Cells.

Basophils and mast cells are known for their capability to release both preformed and newly synthesized inflammatory mediators. In this chapter, we describe how to stimulate and detect histamine released from basophils in whole blood, purified basophils, in vitro cultured mast cells, and in situ skin mast cells (the latter by microdialysis), using either a solid phase assay or flow cytometry. We also give an example of an activation protocol for basophil and mast cell cytokine release and discuss approaches for cytokine detection.

Detection of Mast Cells and Basophils by Immunohistochemistry.

Staining cells or tissues with basic dyes was the mainstay of mast cell and basophil detection methods for more than a century following the first identification of these cell types using such methods. These techniques have now been largely supplanted by immunohistochemical procedures with monoclonal antibodies directed against unique constituents of these cell types. Immunohistochemistry with antibodies specific for the granule protease tryptase provides a more sensitive and discriminating means for detecting mast cells than using the classical histochemical procedures, and using antibodies specific for products of basophils (2D7 antigen and basogranulin) has allowed detection of basophils that infiltrate into tissues. The application of immunohistochemistry to detect more than one marker in the same cell has underpinned concepts of mast cell heterogeneity based on differential expression of chymase and other proteases. The double labeling procedures employed have also provided a means for investigating the expression of cytokines and a range of other products. Protocols are here set out that have been used for immunohistochemical detection of mast cells and basophils and their subpopulations in human tissues. Consideration is given to pitfalls to avoid and to a range of alternative approaches.

Gene Silencing Approaches in Mast Cells and Primary Human Basophils.

The ability to silence gene expression is an invaluable tool for elucidating the importance of intracellular signaling proteins which contribute to the effector functions of mast cells and basophils. However, primary mast cells and their terminally differentiated blood counterpart, basophils, pose a difficult challenge for gene silencing approaches given not only their state of maturation and difficulty to transfect but also because their functions are readily altered by cell handling conditions. Here, we describe a method using lipofection which has been successfully employed to silence gene expression using siRNA in human LAD2 mast cells as well as primary human basophils.

Identification of Murine Basophils by Flow Cytometry and Histology.

Here, we describe how murine basophils can be detected in vivo by flow cytometry and immunofluorescence staining. Basophils constitute a homogeneous population of CD4-CD19-CD49b+IgE+ cells in flow cytometric analysis. When IgE levels are low, one can also use anti-FcεRI or anti-CD200R3 antibodies instead of anti-IgE. For immunofluorescence staining, we use an anti-Mcpt8 antibody since Mcpt8 is a specific marker for murine basophils. We describe how to prepare the tissue to cut cryo-sections and how to perform the staining using a tyramide-based amplification kit.

Biomarkers of severity and threshold of allergic reactions during oral peanut challenges.

BACKGROUND: Oral food challenge (OFC) is the criterion standard to assess peanut allergy (PA), but it involves a risk of allergic reactions of unpredictable severity. OBJECTIVE: Our aim was to identify biomarkers for risk of severe reactions or low dose threshold during OFC to peanut. METHODS: We assessed Learning Early about Peanut Allergy study, Persistance of Oral Tolerance to Peanut study, and Peanut Allergy Sensitization study participants by administering the basophil activation test (BAT) and the skin prick test (SPT) and measuring the levels of peanut-specific IgE, Arachis hypogaea 2-specific IgE, and peanut-specific IgG4, and we analyzed the utility of the different biomarkers in relation to PA status, severity, and threshold dose of allergic reactions to peanut during OFC. RESULTS: When a previously defined optimal cutoff was used, the BAT diagnosed PA with 98% specificity and 75% sensitivity. The BAT identified severe reactions with 97% specificity and 100% sensitivity. The SPT, level of Arachis hypogaea 2-specific IgE, level of peanut-specific IgE, and IgG4/IgE ratio also had 100% sensitivity but slightly lower specificity (92%, 93%, 90%, and 88%, respectively) to predict severity. Participants with lower thresholds of reactivity had higher basophil activation to peanut in vitro. The SPT and the BAT were the best individual predictors of threshold. Multivariate models were superior to individual biomarkers and were used to generate nomograms to calculate the probability of serious adverse events during OFC for individual patients. CONCLUSIONS: The BAT diagnosed PA with high specificity and identified severe reactors and low threshold with high specificity and high sensitivity. The BAT was the best biomarker for severity, surpassed only by the SPT in predicting threshold. Nomograms can help estimate the likelihood of severe reactions and reactions to a low dose of allergen in individual patients with PA.

Acid Stripping of Surface IgE Antibodies Bound to FcεRI is Unsuitable for the Functional Assays that Require Long-Term Culture of Basophils and Entire Removal of Surface IgE.

Basophils are rare granulocytes and dysregulated functions of these cells are associated with several atopic and non-atopic allergic diseases of skin, respiratory system and gastrointestinal tract. Both cytokines and immunoglobulin E (IgE) are implicated in mediating the basophil activation and pathogenesis of these disorders. Several reports have shown that healthy individuals, and patients with allergic disorders display IgG autoantibodies to IgE and hence functional characterization of these anti-IgE IgG autoantibodies is critical. In general, anti-IgE IgG autoantibodies modulate basophil activation irrespective of allergen specificity by interacting with constant domains of IgE. Therefore, an ideal solution to prove the functions of such anti-IgE IgG autoantibodies would be to completely eliminate type I high affinity immunoglobulin E receptor (FcɛRI)-bound IgE from the surface of basophils and to demonstrate in an unequivocal manner the role of anti-IgE IgG autoantibodies. In line with previous reports, our data show that FcɛRI on peripheral blood basophils are almost saturated with IgE. Further, acetic acid buffer (pH 4) efficiently removes these FcɛRI-bound IgE. Although immediately following acetic acid-elution of IgE had no repercussion on the viability of basophils, following 24 hours culture with interleukin-3 (IL-3), the viability and yield of basophils were drastically reduced in acid-treated cells and had repercussion on the induction of activation markers. Lactic acid treatment on the other hand though had no adverse effects on the viability of basophils and IL-3-induced activation, it removed only a small fraction of the cell surface bound IgE. Thus, our results show that acid buffers could be used for the elution of FcɛRI-bound IgE on the basophil surface for the biochemical characterization of IgE antibodies or for the immediate use of basophils to determine their sensitivity to undergo degranulation by specific allergens. However, these methods are not utile for the functional assays of basophils that require longer duration of culture and entire removal of surface IgE to validate the role of anti-IgE IgG autoantibodies that interact with FcɛRI-bound IgE irrespective of allergen specificity.

Giant Plasma Membrane Vesicles: An Experimental Tool for Probing the Effects of Drugs and Other Conditions on Membrane Domain Stability.

Giant plasma membrane vesicles (GPMVs) are isolated directly from living cells and provide an alternative to vesicles constructed of synthetic or purified lipids as an experimental model system for use in a wide range of assays. GPMVs capture much of the compositional protein and lipid complexity of intact cell plasma membranes, are filled with cytoplasm, and are free from contamination with membranes from internal organelles. GPMVs often exhibit a miscibility transition below the growth temperature of their parent cells. GPMVs labeled with a fluorescent protein or lipid analog appear uniform on the micron-scale when imaged above the miscibility transition temperature, and separate into coexisting liquid domains with differing membrane compositions and physical properties below this temperature. The presence of this miscibility transition in isolated GPMVs suggests that a similar phase-like heterogeneity occurs in intact plasma membranes under growth conditions, albeit on smaller length scales. In this context, GPMVs provide a simple and controlled experimental system to explore how drugs and other environmental conditions alter the composition and stability of phase-like domains in intact cell membranes. This chapter describes methods to generate and isolate GPMVs from adherent mammalian cells and to interrogate their miscibility transition temperatures using fluorescence microscopy.

[Determination of a new cow's milk-based formula allergenic capacity in 7 infants]. / Determinación de la capacidad alergénica de una nueva fórmula infantil a base de leche de vaca en 7 lactantes.

BACKGROUND: Cow's milk protein allergy is the main allergic problem during the first year of life, possibly owing to immune and gastrointestinal systems poor maturation. To prevent allergic reactions, the content and type of proteins in infant formulas resemble those of breast milk. We believe that reactions are due rather to the amount than to the type of protein. OBJECTIVE: To design a new formula with cow's milk that provides the infant with the main nutrients at an affordable cost and with lower risk for the development of allergies. METHODS: Three-phase project: product design, industrial production and ex vivo assay to assess for anemia and type I allergic reaction by CD63 expression in basophils. RESULTS: For every 100 calories, the content of protein was 2.0 g, carbohydrates 7.2 g and fat 0.5 g, which is higher than the indicated maximum value (4.5 g). Microbiologically, it was an innocuous food. CD63 expression was low in 57.1% of the babies and high in 42.9%. CONCLUSION: The new formula did not trigger any allergenic responses and can therefore be supplied to non-atopic infants.

Antecedentes: La alergia a las proteínas de la leche de vaca es el principal problema alérgico durante el primer año de vida, debido a la poca maduración de los sistemas inmunológico y gastrointestinal. Para evitar reacciones alérgicas, el contenido y tipo de proteínas de las fórmulas infantiles se asemejan a los de la leche materna. Conforme un principio de alergología, probablemente las reacciones se deben a la cantidad de proteínas más que al tipo. Objetivo: Diseñar una nueva fórmula con leche de vaca que aporte al lactante los principales nutrientes, a un bajo costo y con menor riesgo de padecer alergias. Métodos: Proyecto realizado en 3 fases: diseño del producto, producción industrial y ensayo ex vivo para evaluar mediante la expresión del CD63 en basófilos la presencia de anemia y reacción alérgica tipo I en lactantes. Resultados: Por cada 100 calorías, el contenido de proteínas fue de 2 g, de carbohidratos de 7.2 g y de grasa de 0.5 g, mayor al valor máximo indicado (4.5 g). Microbiológicamente, la fórmula láctea propuesta se trató de un alimento inocuo. La expresión del CD63 fue baja en 57.1 % de los lactantes y alta en 42.9 %. Conclusión: La nueva fórmula no desencadenó respuesta alergénica, por lo tanto, puede suministrarse a lactantes no atópicos.

Morphologic and Cytochemical Characteristics of the Blood Cells of the Yellow-Bellied Slider (Trachemys scripta scripta).

The increasing prevalence of yellow-bellied sliders (Trachemys scripta scripta) as pets in the European Union and also its utilization as animal models for experimental purposes makes crucial an accurate classification of their blood cells. The aim of this work was to provide a morphologic classification based on the cytochemical characteristics of the blood cells of 15 yellow-bellied sliders. Cytochemical stains included benzidine peroxidase, chloroacetate esterase, alpha-naphthyl butyrate esterase (with and without sodium fluoride), acid phosphatase (with and without tartaric acid), Sudan black B, periodic acid-Schiff and toluidine blue. Nuclear and cellular dimensions were also measured based on quick Romanowsky-type stained smears. Besides erythrocytes and thrombocytes, five types of white blood cells were identified: heterophils, eosinophils, basophils, lymphocytes and monocytes. The cytochemical patterns of heterophils, eosinophils and basophils were unique compared to those described for other chelonians. This paper provides a useful guideline for clinical settings and further haematological studies of this species.

Basophil CD63 expression in chronic spontaneous urticaria: correlation with allergic sensitization, serum autoreactivity and basophil reactivity.

BACKGROUND: The underlying causes and factors contributing to the disease severity of chronic spontaneous urticaria (CSU) are unknown. OBJECTIVE: Given the important role of basophils in the pathogenesis of urticaria and that CD63 serves as a useful marker for basophil activation and detecting, CD63 expression of basophils is a reliable tool for diagnosing allergy and hypersensitivity reactions to different allergens; the objective of this study was to investigate whether the level of basophil CD63 expression is correlated with allergen sensitization, serum autoreactivity and basophil reactivity in patients with CSU. METHODS: Basophil-enriched leucocytes were separated from the blood of 64 patients with chronic urticaria (54 CSU patients and 10 symptomatic dermographism patients), 18 healthy control subjects and seven atopic donors without urticaria. Flow cytometry was then used to detect CD63 expression on the cell membrane of basophils from all samples. Analysis was also preformed on basophils incubated with sera from CSU patients with positive or negative autologous serum skin test (ASST). RESULTS: CD63 expression was significantly higher in the basophils from patients with CSU than in those from patients with symptomatic dermographism and the healthy control group. The levels of CD63 expression in CSU patients with ASST+ and/or allergen sensitization were higher than those with ASST- and/or no allergen sensitization patients. Incubation with ASST+ serum resulted in an increased expression of CD63 in the basophils of ASST+ CSU patients, whereas no such response was observed in healthy controls or ASST- CSU patients. CONCLUSION: The increased CD63 expression in basophils from CSU patients may correlate with allergen sensitization, autoreactivity of serum and basophil reactivity. Our results suggest that CD63 may contribute new insight into the pathogenesis of CSU.

Single-step enrichment of basophils from human peripheral blood by a novel method using a Percoll density gradient.

We have developed a novel continuous flow-through cell separation method using a Percoll density gradient. This method can continuously separate a large number of cells into five fractions according to their densities. To apply this method to the separation of basophils, Percoll density gradients were modified to improve basophil enrichment. When a set of Percoll density gradients was prepared (1.071, 1.075, 1.080, 1.084, and 1.090 g/mL) the basophils in a healthy volunteer were enriched by an average of 23.1 and 63.5% at Percoll densities of 1.075 (fraction 3) and 1.080 g/mL (fraction 4), respectively. On average, the yield of basophils was 1.66 × 10(5) cells in fraction 3 and 1.61 × 10(5) cells in fraction 4 from 9 mL of peripheral blood. The expression of CD203c (cluster of differentiation 203c) on separated basophils was upregulated by anti-immunoglobulin E stimulation similar to basophils in whole blood. Histamine release induced by calcium ionophore was also observed in the separated basophils. The present method will be useful for basophil enrichment since it preserves their function without using counterflow elutriation and immunological reagents, and this method will be effective as a preparative separation for cell purification by flow cytometry.

Measuring histamine and cytokine release from basophils and mast cells.

Basophils and mast cells are known for their capability to release both preformed and newly synthesized inflammatory mediators. In this chapter we describe how to stimulate and detect histamine released from basophils in whole blood, purified basophils, in vitro cultured mast cells, and in situ skin mast cells. We also give an example of an activation protocol for basophil and mast cell cytokine release and discuss approaches for cytokine detection.

Expression and function of Angiopoietins and their tie receptors in human basophils and mast cells.

The Angiopoietin/Tie system is a key regulator of vascular remodeling, maturation, angiogenesis and lymphangiogenesis. In humans there are three angiopoietins: Angiopoietin-1 (Ang1), Angiopoietin-2 (Ang2), and Angiopoietin-4 (Ang4). Ang1 and Ang2 are the best characterized angiopoietins. The angiopoietin receptor system consists of two type I tyrosine kinase receptors (Tie1 and Tie2). Tie2 binds all known angiopoietins. We sought to characterize Ang1, Ang2, Tie1 and Tie2 expression and functions in human basophils and mast cells. Basophils, LAD-2 cells and Human Lung Mast Cells (HLMCs) constitutively express Ang1 and Ang2 mRNA. Intracellular staining for Ang1 and Ang2 was stronger in basophils than in mast cells. Immunoelectron microscopy demonstrated Ang1 in cytoplasmic vesicles of basophils. The protein kinase C activators phorbol diester (PMA) and bryostatin 1 (Bryo1) stimulated basophils to rapidly release a large amount of Ang1. PMA-induced Ang1 release was inhibited by brefeldin A. Tie1 and Tie2 mRNAs were expressed in basophils, LAD-2 and HLMCs. Basophils, LAD-2 and HLMCs expressed Tie1 on the cell surface. HLMCs and LAD-2 expressed Tie2 on the cell surface, whereas basophils did not. Ang1, but not Ang2, induced migration of mast cells through the engagement of Tie2. Neither Ang1 nor Ang2 induced basophil chemotaxis. We have identified a novel mechanism of cross-talk between human basophils and mast cells mediated by the Ang1/Tie2 system that might be relevant in the orchestration of inflammatory and neoplastic angiogenesis.

Age and gender related changes in hematological parameters of thoroughbred foals.

Hematological and biochemical profiles commonly are required in equine medicine. We studied hematological parameters including red blood cells (RBC), white blood cells (WBC), hemoglobin (Hb), hematocrit (PCV), differential leukocyte counts, mean cell volume (MCV), mean corpuscular hemoglobin (MCH), and mean corpuscular hemoglobin concentration (MCHC) in thoroughbred foals at different ages and for both sexes. Sixty healthy thoroughbred foals, 1 day, 3 days and 1 year old were used. Each age group consisted of 10 male and 10 female animals. We found significant differences related to age in RBC values of females, PCV, MCV values of males, WBC, neutrophil percentages, lymphocyte percentages, monocyte percentages of females, and eosinophil percentages and basophil percentages. Significant differences related to gender were found only with regard to PCV at 1 year and WBC at 1 day. The hematological parameters of thoroughbred foals up to one year old may be useful for evaluating and monitoring the health of these animals.

Evaluation of peripheral blood basophil activation by means of surface plasmon resonance imaging.

Basophil activation in response to antigen may represent specificities of type I allergy of individuals and their reactions in the body. We previously demonstrated that surface plasmon resonance (SPR) sensor could detect the activation of human basophils in response to antigens. In this study, we further developed a technique based on SPR imaging (SPRI) system to detect reactions of individual basophils isolated from human blood, and investigated the potential of this sensor as a tool for diagnosis of type I allergy. To detect the change of refractive index (RI) in individual basophils, human basophils were isolated by negative selection with antibodies conjugated with magnetic beads, fixed on a gold film with anti-basophil antibody and stimulated with various antigens under the measurement of SPRI. The sensor could detect the reactions of individual basophils in response to specific antigens as well as non-specific activators. Moreover, the sensor well allocated two spots of basophils on a sensor chip and detected individual reactions to antigen. Thus, the technique developed in this study can visualize the effect of various stimuli or inhibitors on basophils as change of intracellular RI distribution at the single cell level. In combination with a device to rapidly isolate basophils from peripheral blood, this technique may be a useful tool as a high throughput screening system in clinical diagnosis for type I allergy.

The history of the controversial relationship between mast cells and basophils.

Work on mast cells and basophils began with their identification by Paul Ehrlich at the end of the 19th century. Mast cells and basophils were immediately perceived as closely linked cells and early nomenclature formulated by Ehrlich himself, i.e., tissue "Mastzellen" and blood "Mastzellen", reflected this unifying viewpoint. With time, important functional affinities but also substantial diversities were recognized. This review article focuses on the historical development of the concept of mast cell/basophil specificity, from the initial identification of these cells to current studies.

A comparison study of detecting gold nanorods in living cells with confocal reflectance microscopy and two-photon fluorescence microscopy.

Two-photon fluorescence microscopy and confocal reflectance microscopy were compared to detect intracellular gold nanorods in rat basophilic leukaemia cells. The two-photon photoluminescence images of gold nanorods were acquired by an 800 nm fs laser with the power of milliwatts. The advantages of the obtained two-photon photoluminescence images are high spatial resolution and reduced background. However, a remarkable photothermal effect on cells was seen after 30 times continuous scanning of the femto-second laser, potentially affecting the subcellular localization pattern of the nanorods. In the case of confocal reflectance microscopy the images of gold nanorods can be obtained with the power of light source as low as microwatts, thus avoiding the photothermal effect, but the resolution of such images is reduced. We have noted that confocal reflectance images of cellular gold nanorods achieved with 50 microW 800 nm fs have a relatively poor resolution, whereas the 50 microW 488 nm CW laser can acquire reasonably satisfactory 3D reflectance images with improved resolution because of its shorter wavelength. Therefore, confocal reflectance microscopy may also be a suitable means to image intracellular gold nanorods with the advantage of reduced photothermal effect.

Combined analysis of intracellular signalling and immunophenotype of human peripheral blood basophils by flow cytometry: a proof of concept.

BACKGROUND: The signal transduction pathways and control mechanisms involved in IgE-mediated basophil activation remain incompletely understood. OBJECTIVES: To investigate whether basophilic intracellular signal transduction and immunophenotype can be analysed simultaneously by flow cytometry. METHODS: Basophils in whole blood were stimulated with anti-IgE and latex antigen at various concentrations and during different time courses. Phosphorylation of p38 mitogen-activated protein kinase (MAPK) as a representative of the intracellular signal transduction pathway and surface expression of CD63 was assessed simultaneously flow cytometrically. The effect of pre-incubation with IL-3 was assessed. RESULTS: Stimulation of the basophils with anti-IgE and allergen induces a rapid phosphorylation of p38 MAPK that peaks between 1 and 5 min and returns to baseline levels after 60 min. In contrast, CD63 up-regulation demonstrates a maximal but more continuous expression that peaks approximately 5 min later than phosphorylation of p38 MAPK. Specific inhibition of p38 MAPK reduced or almost completely abrogated up-regulation of CD63. Pre-incubation of the basophils with IL-3 produces a rapid p38 MAPK phosphorylation over basal levels, but this was weaker and shorter than for anti-IgE stimulation. Pre-incubation of the basophils with IL-3 did not potentiate anti-IgE-induced phosphorylation of p38 MAPK and did affect spontaneous or IgE-mediated CD63 up-regulation. CONCLUSIONS: This study provides the proof that the flow cytometer allows an integrated analysis of basophilic intracellular signalling and immunophenotyping. Owing to its technical simplicity, the low number of cells required and rapid analysis, the technique seems promising for use in the clinic as a diagnostic tool or to monitor therapy. CAPSULE SUMMARY: This study is the first to provide evidence for a combined analysis of basophilic intracellular signalling and immunophenotyping by flow cytometry. Owing to its technical simplicity, the low number of cells required and rapid analysis, the technique seems promising for use in the clinic as a diagnostic tool or to monitor therapy.