Development of Specific Fluorogenic Substrates for Human ß-N-Acetyl-D-hexosaminidase A for Cell-Based Assays.

Inhibitors of human ß-N-acetyl-D-hexosaminidase (hHEX) A and human O-GlcNAcase (hOGA) reportedly play roles in multiple diseases, suggesting their potential for pharmacological chaperone (PC) therapy of Sandhoff disease (SD) and Tay-Sachs disease (TSD), as lysosomal storage diseases, and Alzheimer's disease and progressive supranuclear palsy, respectively. In particular, hHEXA inhibitors as PCs have been shown to successfully enhance hHEXA levels, leading to the chronic form of SD and TSD. In the diagnosis of enzyme deficiencies in SD and TSD, artificial hHEXA substrates based on 4-methylumbelliferone as a fluorophore are available and generally used; however, they do not have sufficient performance to screen for potential inhibitors for a PC therapy from compound libraries. Further, there are currently few fluorogenic substrates for hHEXA suitable for such requirements and there are no substrates ideal for cell-based inhibitor screening. Here, we clarified the difference in enzyme active site structure between hHEXA and hOGA from their tertiary structures. To develop lysosome-localized hHEXA-specific fluorogenic substrates based on the difference in their active site structures, our developed quinone methide cleavage substrate design platform was applied for the molecular design of substrates. Thereafter, we synthesized via the shortest route and evaluated novel three-color fluorogenic substrates for hHEXA that exhibited excellent specificity and sensitivity in three human cell lines. The designed substrates represent the first-in-a class of new substrates that can be utilized to screen hHEXA inhibitors in adherent human cultured cells.

Mast cell activation markers for in vitro study.

Mast cells (MCs) are well known for their role in allergic conditions. This cell can be activated by various types of secretagogues, ranging from a small chemical to a huge protein. Mast cell activation by secretagogues triggers the increase in intracellular calcium (iCa2+) concentration, granule trafficking, and exocytosis. Activated mast cells release their intra-granular pre-stored mediator or the newly synthesized mediator in the exocytosis process, in the form of degranulation or secretion. There are at least three types of exocytosis in mast cells, which are suggested to contribute to the release of different mediators, i.e.,, piecemeal, kiss-and-run, and compound exocytosis. The status of mast cells, i.e., activated or resting, is often determined by measuring the concentration of the released mediator such as histamine or ß-hexosaminidase. This review summarizes several mast cell components that have been and are generally used as mast cell activation indicator, from the classical histamine and ß-hexosaminidase measurement, to eicosanoid and granule trafficking observation. Basic principle of the component determination is also explained with their specified research application and purpose. The information will help to predict the experiment results with a certain study design.

Detection and identification of O-GlcNAc-modified proteins using 6-azido-6-deoxy-N-acetyl-galactosamine.

An unnatural monosaccharide with a C6-azide, Ac36AzGalNAc, has been developed as a potent and selective probe for O-GlcNAc-modified proteins. Combined with click chemistry, we demonstrate that Ac36AzGalNAc can robustly label O-GlcNAc glycosylation in a wide range of cell lines. Meanwhile, cell imaging and LC-MS/MS proteomics verify its selective activity on O-GlcNAc. More importantly, the protocol presented here provides a general methodology for tracking, capturing and identifying unnatural monosaccharide modified proteins in cells or cell lysates.

Accurate quantification of ß-hexosaminidase released from laboratory of allergic diseases 2 cells via liquid chromatography tandem mass spectrometry method.

ß-Hexosaminidase is one of the enzymes that is secreted from mast cells via antigen-induced degranulation and has frequently been used as an indicator of anaphylactic reactions. The main method for determining ß-hexosaminidase is indirect, "substrate-based" and shows limitations. Hence, development of an accurate detecting method is particularly important and urgently needed. In this study we developed a liquid chromatography tandem mass spectrometry (LC-MS/MS) method for measuring ß-hexosaminidase. Laboratory of allergic diseases 2 (LAD2) cells were stimulated with compound 48/80 (C48/80), the supernatant was collected and subjected to in-solution protein digestion; the obtained peptides were desalted, concentrated, separated and analyzed with an LC-tandem MS instrument. A peptide with the sequence "LAPGTIVEVWK" was selected for quantitative analysis, and four other peptides for qualitative research. The time-effect relationship curve was studied, and the results of the LC-MS/MS method were found to be almost consistent with those obtained via the conventional method. The method was then employed to measure ß-hexosaminidase released from LAD2 cells stimulated with potential allergens, and the results showed that it can be applied to determine the potential allergenicity of drugs. This new method showed good specificity, high sensitivity and a wide application range. It could be used to evaluate allergic reactions, providing a guide for medication safety during clinical testing.

Fermentation-Mediated Enhancement of Ginseng's Anti-Allergic Activity against IgE-Mediated Passive Cutaneous Anaphylaxis In Vivo and In Vitro.

Ginseng (the root of Panax ginseng Meyer) fermented by Lactobacillus plantarum has been found to attenuate allergic responses in in vitro and in vivo experimental models. Ginseng has been reported to also possess various biological functions including anti-inflammatory activity. The present study was aimed at comparing the anti-allergic effect of ginseng and fermented ginseng extracts on IgE-mediated passive cutaneous anaphylaxis in vitro in a murine cell line and in vivo in mice. Fermented ginseng extract (FPG) showed higher inhibitory effect against in vitro and in vivo allergic responses when compared with ginseng extract (PG). The secretion of ß-hexosaminidase and interleukin (IL)-4 from the IgE-DNP-stimulated RBH-2H3 mast cells were significantly (p < 0.05) inhibited by FPG treatment, and this effect was concentration-dependent. Further, MKK4 activation and subsequent JNK phosphorylation were attenuated by FPG treatment. The inhibitory effect of FPG on the in vitro allergic response was verified in vivo against IgE-DNP-induced passive cutaneous anaphylaxis in a mouse model. These data indicated that the fermentation of ginseng with L. plantarum enhanced its anti-allergic effects both in vitro and in vivo. We predict that compositional changes in the ginsenosides caused by the fermentation may contribute to the change in the anti-allergic effects of ginseng. The results of our study highlight the potential of the use of FPG as a potential anti-allergic agent.

In Vitro Biochemical Assays for O-GlcNAc-Processing Enzymes.

O-GlcNAc transferase (OGT) and O-GlcNAcase (OGA) are the only enzymes that regulate the dynamics of protein O-GlcNAcylation. Protein O-GlcNAcylation is an important post-translational modification (PTM) of nuclear and cytoplasmic proteins with O-linked ß-N-acetyl-glucosamine (O-GlcNAc). O-GlcNAc and its enzymes are involved in a wide variety of cellular processes and are linked to the pathological progression of chronic diseases. Considering their emerging biological significance, systematic and rapid methods to determine the activities of OGT and OGA have become essential, and several chemical/biochemical methods for measuring the activities of these enzymes have been developed. This minireview mainly focuses on the various biochemical assay methods developed to date, while also providing a description of the fundamental principles underlying the monitoring of O-GlcNAc enzyme activities.

The activity of N-acetyl-ß-hexosaminidase in boar seminal plasma is linked with semen quality and its suitability for cryopreservation.

The determination of sperm cryotolerance is an important step in the process of developing optimal techniques for the storage of boar semen. The objective of this study was to determine individual proteome variations in boar seminal plasma and spermatozoa and establish their influence on the cryotolerance of ejaculate. Sodium dodecyl sulfate polyacrylamide gel electrophoresis revealed the presence of protein with estimated molecular weight of 90 kDa in sperm extracts from ejaculates of selected boars. In all cases, dialysis performed at the initial stage of cryopreservation effectively removed the protein from sperm cells. The protein had an affinity for Zn(2+) ions. Mass spectrometry revealed similarities between the discussed protein and the ß subunit of N-acetyl-ß-hexosaminidase (ß-HEX). Seminal plasma ß-HEX was purified 252-fold with approximately 27% recovery and specific activity of 1800 U/mg of protein. Enzyme activity in fresh seminal plasma was correlated with superoxide dismutase activity (r = -0.42, P < 0.05), glutathione peroxidase activity (r = -0.42, P < 0.05), mitochondrial function (r = 0.31, P < 0.05), glutathione content (r = 0.34, P < 0.05), total protein content (r = 0.42, P < 0.05), and total oxidant status of seminal plasma (r = 0.37, P < 0.05). After thawing, ß-HEX activity in seminal plasma was negatively correlated with the total motile sperm count (r = -0.33, P < 0.05), plasma membrane integrity (r = -0.31, P < 0.05), and lipid peroxidation (r = 0.33, P < 0.05). The observed correlations indicate that lower levels of ß-HEX activity in boar seminal plasma are linked with higher quality of sperm after thawing. Based on those observations, the ejaculates were divided into two groups characterized by low (<20,000 U/L) and high (>20,000 U/L) levels of ß-HEX activity in seminal plasma. In plasma with high ß-HEX activity, spermatozoa were characterized by lower plasma membrane integrity (84.7%, P < 0.05). Higher glutathione levels (1250.3 µM), higher total protein content (50 mg/mL), and higher total oxidant status (6.82-µmol H2O2 Equiv/L) were also observed (P < 0.05). After thawing, lower sperm motility (20.4%), lower plasma membrane integrity (41.7%), and higher lipid peroxidation (30.9-nM malondialdehyde/10(8) spermatozoa/h) were reported in ejaculates with high seminal plasma ß-HEX activity. The results of this study indicate that ß-HEX activity in seminal plasma is a useful indicator in preliminary evaluations of boar sperm cryotolerance.

Iopromide in combination with IFN-γ induces the activation of HMC-1 cells via IL-4 and MCP-1 expression.

In this study, we investigated whether IFN-γ has a role in contrast-medium-induced adverse reactions. Iopromide, a nonionic iodinated contrast agent, slightly induced mast cell proliferation and significantly increased the expression of IL-4 and MCP-1 at low doses. The pretreatment of cells with IFN-γ dramatically increased the expression of iopromide-induced IL-4 and MCP-1. An evaluation of mast cell activator secretion revealed that IFN-γ- or IL-4-pretreated HMC-1 cells released dramatically increased levels of ß-hexosaminidase and histamine when stimulated with iopromide. We also found that the migration of EoL-1 and THP-1 cells was significantly increased in culture conditions with iopromide-stimulated IL-4-pretreated HMC-1 cells. Taken together, our findings suggest that measuring IFN-γ or IL-4 levels in serum would be helpful as a potential biomarker of adverse patient reactions and that blocking IFN-γ or IL-4 may be crucial in preventing the delayed allergy-like reaction induced by contrast medium in patients with various diseases.

Nasal allergen deposition leads to conjunctival mast cell degranulation in allergic rhinoconjunctivitis.

BACKGROUND: The naso-ocular interaction in allergic rhinoconjunctivitis is well recognized from epidemiological, clinical, and experimental observations. The precise mechanisms remain incompletely understood. A new mouse model of allergic rhinoconjunctivitis was used to investigate the contribution of mast cells and trigeminal ganglia activation to conjunctival (conj.) inflammation after nasal allergen provocation. METHODS: Sensitized mice were exposed to ovalbumin (OVA) via the nose and/or conjunctiva, and conj. homogenates were analyzed for histamine and substance P (using ELISA) and by eosinophil peroxidase (EPO) and beta-hexosaminidase assays. The conj. effects of nasal allergen deposition were compared with those induced by the mast cell activator C48/80 and with pretreatment of the mast cell stabilizer ketotifen or the transient receptor potential channel receptor (TRP) agonist capsaicin. Protachykinin 1 (TAC1) expression was quantified in the trigeminal ganglia using real time polymerase chain reaction. RESULTS: At 1 hour after nasal application of OVA, increased conj. levels of beta-hexosaminidase (0.68 ± 0.03 nm versus 0.56 ± 0.02 nm; p = 0.02), histamine (751.1 ± 52.17 ng/mL versus 546.3 ± 76.91 ng/mL; p = 0.05), and EPO (0.66 ± 0.09 nm versus 0.37 ± 0.03 nm; p = 0.02) were detected compared with saline. Higher levels of TAC1 expression were found in the trigeminal ganglia at 24 hours after OVA application (1326 ± 255 versus 687.5 ± 90.77 TAC1/beta-actin; p = 0.04). Nasal challenge with C48/80 increased substance P and beta-hexosaminidase levels in the conjunctiva, as well as TAC1 expression. Pretreatment with ketotifen resulted in lower levels of substance P as well as TAC1 expression. Destruction of sensory nerves in the nose by capsaicin reduced the OVA-induced conj. levels of substance P, histamine, and beta-hexosaminidase. CONCLUSION: Nasal allergen deposition in sensitized mice induced trigeminal TAC1 expression and conj. mast cell degranulation. These data represent a significant step forward in understanding the close interaction between nasal and conj. inflammation in allergy.

Fungal exposure and low levels of IL-10 in patients with sarcoidosis.

BACKGROUND AND OBJECTIVES: Sarcoidosis is an inflammatory disease with increased levels of inflammatory cytokines. Previous studies have shown a relation between the degree of granuloma infiltration and serum cytokine levels, except for interleukin- (IL-) 10. The aim of the study was to further investigate the serum levels of IL-10 in patients with sarcoidosis and relate them to fungal exposure in terms of the amount of fungi in the air of their homes and ß-glucan in bronchoalveolar lavage (BAL) fluid. METHODS: Patients with sarcoidosis (n = 71) and healthy controls (n = 27) were enrolled. IL-10 was determined in serum. BAL was performed and the amount of ß-glucan was measured. Domestic exposure to fungi was determined by measuring airborne ß-N-acetylhexosaminidase (NAHA) in the bedrooms. RESULTS: At high levels of fungal exposure (domestic fungal exposure and ß-glucan in BAL), serum IL-10 values were lower than at low and intermediate exposure levels. CONCLUSION: The low serum IL-10 values at high fungal exposure suggest that fungal cell wall agents play a role in granuloma formation in sarcoidosis by inhibiting the secretion of the anti-inflammatory cytokine IL-10.

Allergenicity potential of red kidney bean (Phaseolus vulgaris L.) proteins in orally treated BALB/c mice and passively sensitized RBL-2H3 cells.

Red kidney bean (Phaseolus vulgaris L.) is one the most commonly consumed legumes that requires an in depth understanding of its allergenicity. Therefore, the aim of this study was to explore the allergenicity of red kidney bean proteins following oral exposure in BALB/c mice and elucidate the levels of Th1/Th2 transcription factors induced by red kidney bean proteins in rat basophilic leukemia cells (RBL-2H3 cells) passively sensitized with the sera of red kidney bean sensitized mice. Red kidney bean proteins showed enhanced levels of total and specific IgE, anaphylactic symptoms, thymic stromal lymphopoietin (TSLP) and peritoneal albumin over control. Enhanced release of ß-hexosaminidase along with up regulated expressions of GATA-3, STAT-6, T-bet, c-MAF and NFAT were observed in the RBL-2H3 cells exposed with red kidney bean proteins when compared to that of the controls. Taken together, exposure of red kidney bean proteins may cause allergic symptoms in mice and the ambivalent effect on Th2/Th1 transcription factors in RBL-2H3 cells.

Assessment of dermal safety of Scutellaria baicalensis aqueous extract topical application on skin hypersensitivity.

Scutellaria baicalensis has been used as a traditional herbal medicine for bronchitis, hepatitis, and allergic diseases. The root of Scutellaria baicalensis contains active flavonoid components, including baicalin, baicalein, wogonoside, and wogonin, which have pharmaceutical properties. In the present study, the antiallergic properties of a standardized aqueous extract of S. baicalensis were evaluated, and the skin toxicity of its dermal application was also determined. The in vivo and in vitro assays were performed by using the ß-hexosaminidase assay in rat basophilic leukemia cells (RBL-2H3) and cutaneous skin reaction in BALB/c mice, respectively. In addition, the acute dermal irritation/corrosion test was carried out in New Zealand white rabbits, and the skin sensitization test was conducted by Buhler's method in Hartley guinea pigs to estimate the safety of the standardized aqueous extract of S. baicalensis for topical application. ß-Hexosaminidase release in RBL-2H3 was markedly decreased following treatment with the standardized aqueous extract of S. baicalensis. It also ameliorated antigen-induced ear swelling compared with the control group in BALB/c mice. In the toxicological studies, it did not induce any dermal irritation/corrosion in rabbits or skin sensitization in guinea pigs. Although still limited, these results concerning the toxicological effects of S. baicalensis could be an initial step toward the topical application of S. baicalensis extracts on hypersensitive skin.

Impact of O-GlcNAc on cardioprotection by remote ischaemic preconditioning in non-diabetic and diabetic patients.

AIMS: Post-translational modification of proteins by O-linked ß-N-acetylglucosamine (O-GlcNAc) is cardioprotective but its role in cardioprotection by remote ischaemic preconditioning (rIPC) and the reduced efficacy of rIPC in type 2 diabetes mellitus is unknown. In this study we achieved mechanistic insight into the remote stimulus mediating and the target organ response eliciting the cardioprotective effect by rIPC in non-diabetic and diabetic myocardium and the influence of O-GlcNAcylation. METHODS AND RESULTS: The cardioprotective capacity and the influence on myocardial O-GlcNAc levels of plasma dialysate from eight healthy volunteers and eight type 2 diabetic patients drawn before and after subjection to an rIPC stimulus were tested on human isolated atrial trabeculae subjected to ischaemia/reperfusion injury. Dialysate from healthy volunteers exposed to rIPC improved post-ischaemic haemodynamic recovery (40 ± 6 vs. 16 ± 2%; P < 0.01) and increased myocardial O-GlcNAc levels. Similar observations were made with dialysate from diabetic patients before exposure to rIPC (43 ± 3 vs. 16 ± 2%; P < 0.001) but no additional cardioprotection or further increase in O-GlcNAc levels was achieved by perfusion with dialysate after exposure to rIPC (44 ± 4 and 42 ± 5 vs. 43 ± 3%; P = 0.7). The glutamine:fructose-6-phosphate amidotransferase (GFAT) inhibitor azaserine abolished the cardioprotective effects and the increment in myocardial O-GlcNAc levels afforded by plasma from diabetic patients and healthy volunteers treated with rIPC. CONCLUSIONS: rIPC and diabetes mellitus per se influence myocardial O-GlcNAc levels through circulating humoral factors. O-GlcNAc signalling participates in mediating rIPC-induced cardioprotection and maintaining a state of inherent chronic activation of cardioprotection in diabetic myocardium, restricting it from further protection by rIPC.

Effects of peanut-skin procyanidin A1 on degranulation of RBL-2H3 cells.

Peanut skin contains large amounts of polyphenols having antiallergic effects. We found that a peanut-skin extract (PSE) inhibits the degranulation induced by antigen stimulation of rat basophilic leukemia (RBL-2H3) cells. A low-molecular-weight fraction from PSE, PSEL, also had inhibitory activity against allergic degranulation. A main polyphenol in PSEL was purified by gel chromatography and fractionated by YMC-gel ODS-AQ 120S50 column. Electrospray ionization mass spectrometry (ESI-MS) analysis of the purified polyphenol gave m/z 599 [M+Na]⁺. Based on the results of ¹H-NMR, ¹³C-NMR spectra, and optical rotation analysis, the polyphenol was identified as procyanidin A1. It inhibited the degranulation caused by antigen stimulation at the IC50 of 20.3 µM. Phorbol-12-myristate-13-acetate (PMA) and 2,5,-di(tert-butyl)-1,4-hydroquinone (DTBHQ)-induced processes of degranulation were also inhibited by procyanidin A1. These results indicate that peanut-skin procyanidin A1 inhibits degranulation downstream of protein kinase C activation or Ca²âº influx from an internal store in RBL-2H3 cells.

Identification of biofilm matrix-associated proteins from an acid mine drainage microbial community.

In microbial communities, extracellular polymeric substances (EPS), also called the extracellular matrix, provide the spatial organization and structural stability during biofilm development. One of the major components of EPS is protein, but it is not clear what specific functions these proteins contribute to the extracellular matrix or to microbial physiology. To investigate this in biofilms from an extremely acidic environment, we used shotgun proteomics analyses to identify proteins associated with EPS in biofilms at two developmental stages, designated DS1 and DS2. The proteome composition of the EPS was significantly different from that of the cell fraction, with more than 80% of the cellular proteins underrepresented or undetectable in EPS. In contrast, predicted periplasmic, outer membrane, and extracellular proteins were overrepresented by 3- to 7-fold in EPS. Also, EPS proteins were more basic by ∼2 pH units on average and about half the length. When categorized by predicted function, proteins involved in motility, defense, cell envelope, and unknown functions were enriched in EPS. Chaperones, such as histone-like DNA binding protein and cold shock protein, were overrepresented in EPS. Enzymes, such as protein peptidases, disulfide-isomerases, and those associated with cell wall and polysaccharide metabolism, were also detected. Two of these enzymes, identified as ß-N-acetylhexosaminidase and cellulase, were confirmed in the EPS fraction by enzymatic activity assays. Compared to the differences between EPS and cellular fractions, the relative differences in the EPS proteomes between DS1 and DS2 were smaller and consistent with expected physiological changes during biofilm development.

Influence of FAS on murine mast cell maturation.

BACKGROUND: FAS has been shown to be involved in the regulation of many immune processes by induction of cellular apoptosis. However, accumulated evidence shows that FAS signaling also exhibits nonapoptotic functions, such as induction of cell proliferation and differentiation. FAS is the only death receptor known to be expressed on murine mast cells (MCs). OBJECTIVE: To evaluate the role of FAS on murine MC maturation. METHODS: Mouse bone marrow-derived MCs (BMMCs) or peritoneal MCs were derived from FAS-deficient, FASlpr/lpr, and congenic wild-type strains. The MC degranulation and cytokine release after IgE activation was assessed by measuring ß-hexosaminidase, interleukin 13, and tumor necrosis factor α release. Transmission electron microscopy analysis was performed to evaluate the level of BMMC maturation. The surface markers and intracellular preformed mediators were measured as well. RESULTS: Our data reveal that FAS deficiency has an impact on IgE-dependent activation of BMMCs, resulting in a significant decrease in ß-hexosaminidase, interleukin 13, and tumor necrosis factor α release. The total content of preformed mediators (eg, tryptase and ß-hexosaminidase) was reduced in BMMCs derived from FAS-deficient mice. We also found that the level of FcεRI in peritoneal mast cells from FAS-deficient mice was significantly diminished. FAS deficiency also influenced the kinetics of BMMC maturation as was revealed by transmission electron microscopy analysis. CONCLUSION: Our data show that FAS has an impact on the regulation of mouse MC maturation in vitro.

Gangliosides inhibit bee venom melittin cytotoxicity but not phospholipase A(2)-induced degranulation in mast cells.

Sting accident by honeybee causes severe pain, inflammation and allergic reaction through IgE-mediated anaphylaxis. In addition to this hypersensitivity, an anaphylactoid reaction occurs by toxic effects even in a non-allergic person via cytolysis followed by similar clinical manifestations. Auto-injectable epinephrine might be effective for bee stings, but cannot inhibit mast cell lysis and degranulation by venom toxins. We used connective tissue type canine mast cell line (CM-MC) for finding an effective measure that might inhibit bee venom toxicity. We evaluated degranulation and cytotoxicity by measurement of ß-hexosaminidase release and MTT assay. Melittin and crude bee venom induced the degranulation and cytotoxicity, which were strongly inhibited by mono-sialoganglioside (G(M1)), di-sialoganglioside (G(D1a)) and tri-sialoganglioside (G(T1b)). In contrast, honeybee venom-derived phospholipase A(2) induced the net degranulation directly without cytotoxicity, which was not inhibited by G(M1), G(D1a) and G(T1b). For analysis of distribution of Gα(q) and Gα(i) protein by western blotting, lipid rafts were isolated by using discontinuous sucrose gradient centrifuge. Melittin disrupted the localization of Gα(q) and Gα(i) at lipid raft, but gangliosides stabilized the rafts. As a result from this cell-based study, bee venom-induced anaphylactoid reaction can be explained with melittin cytotoxicity and phospholipase A(2)-induced degranulation. Taken together, gangliosides inhibit the effect of melittin such as degranulation, cytotoxicity and lipid raft disruption but not phospholipase A(2)-induced degranulation in mast cells. Our study shows a potential of gangliosides as a therapeutic tool for anaphylactoid reaction by honeybee sting.

The relative allergenicity of Stachybotrys chartarum compared to house dust mite extracts in a mouse model.

A report by the Institute of Medicine suggested that more research is needed to better understand mold effects on allergic disease, particularly asthma development. The authors compared the ability of the fungus Stachybotrys chartarum (SCE) and house dust mite (HDM) extracts to induce allergic responses in BALB/c mice. The extracts were administered by intratracheal aspiration (IA) at several doses (0, 2.5, 5, 10, 20, 40, and 80 microg) 4 times over a 4-week period. Three days after the last IA exposure, serum and bronchoalveolar lavage fluid (BALF) were collected. The relative allergenicity of the extracts was evaluated based on the lowest dose that induced a significant response compared to control (0 microg) and the linear regression slope analysis across the dose range. SCE induced a more robust response than HDM for BALF some inflammatory cells (macrophage and neutrophils), whereas HDM induced more robust BALF lymphocyte and eosinophil responses. Although SCE induced a more robust serum total immunoglobulin E (IgE) response than did HDM, the induction of a similar response in a functional, antigen-specific IgE assay required approximately twice as much SCE as HDM. Even though SCE demonstrates the ability to induce allergic responses in the mouse model, considering the importance and relevance of eosinophil, lymphocyte, and antigen-specific IgE in allergic airway disease, it is concluded that HDM is more potent than SCE in the induction of allergic responses. These data suggest a threshold dose for SCE allergy induction. Furthermore, in damp water-damaged environments, exposure to S. chartarum might easily exceed the sensitization threshold for a susceptible population.

Cultivation and characterization of canine skin-derived mast cells.

It is essential to develop a technique to culture purified skin-derived mast cells (SMCs) to facilitate immunological research on allergic diseases in dogs. This study was performed to develop an efficient culture system for canine SMCs and to characterize the cells in comparison to canine bone marrow-derived mast cells (BMMCs). Enzymatically digested skin biopsy samples were cultivated in serum-free AIM-V medium supplemented with recombinant canine stem cell factor. Three to five weeks after the initiation of culture, mast cells were collected by a magnetic activated cell separation system using anti-c-Kit antibody. The collected cells were composed of a uniform population showing morphological characteristics of mast cells with a round or oval nucleus and abundant toluidine blue-positive metachromatic granules in the cytoplasm. The results of flow cytometric analysis for the presence of cell membrane c-Kit and Fc epsilon receptor I (FcepsilonRI) indicated that approximately 90% of the cells were mast cells. The cytoplasmic granules were positive for both tryptase and chymase. Apparent dose-dependent degranulation was induced by antibody-mediated cross-linking of immunoglobulin E (IgE) bound to the cells. These cytological and immunological characteristics observed in SMCs were mostly similar to those observed in BMMCs; however, IgE-mediated degranulation was significantly lower in SMCs than BMMCs. The culture system for canine SMCs developed in this study would be useful in understanding the pathophysiology and developing anti-allergic therapeutics in canine allergic dermatitis.