The authors thank Professor Mei Jiang for her help in the statistical analysis and Mr. Hammer Tsui in the preparation of the manuscript. This study was supported by the Guangzhou Science and Technology Foundation (201804020043) and the National Natural Science Foundation of China (NSFC 81572063 and NSFC 81802076). The funding groups agreed with the study design, data analysis, manuscript preparation, and decision to publish. No other funding was received for this study.

This study and the use of human serum samples were approved by the Ethics Committee of The First Affiliated Hospital of Guangzhou Medical University (GYYY-2016-73). All participants have given their written consent independently or through their parents (in the case of children).
1. Basic information of the study group
NOTE: The Allergy Information Repository of the State Key Laboratory of Respiratory Disease (AIR-SKLRD) is a large serum bank established inside the Guangzhou Institute of Respiratory Hospital (GIRH). Initiated in the last decade, the AIR-SKLRD has already started to collect and store serum samples from patients with allergic diseases, together with their clinical information (Table 1)4,5. The current study was performed with sera from the AIR-SKLRD.
<ol>
	<li>Search the AIR-SKLRD&#8217;s database for sera collected from January 2015 to June 2018 and select the patients with allergic disease, who were found to be sensitive to the common allergens in the region.</li>
	<li>Ensure that all selected patients have allergic-related diseases, such as allergic rhinitis and or asthma, allergic dermatitis, and/or urticaria, and that the serum of these patients contains multiple serum allergen-specific immunoglobulin E (sIgE) sensitizations of common allergens in this region, detected by the System 1.</li>
	<li>Exclude patients with incomplete medical records, those lost to follow-up, those who refuse to give informed consent regarding the use of their serum samples for scientific purposes, those with an identified immunodeficiency, those currently on immunotherapy or immunomodulatory agents, or those found to have parasitic infections.</li>
	<li>Ensure no treatment or drug prescription was given prior to the serum collection so as to minimize interference to the laboratory findings. All serum samples that do not fulfill the criteria were rejected.</li>
</ol>
2. Study flow and measurements of interest
NOTE: The microfluidic system needs 100 &#181;L of serum for determining 19 allergens. Venous blood (5 mL) was collected from each patient using a vacuum blood vessel containing separating gel. After centrifuging for 10 min at 1,000 x g, the upper layer was collected for testing. Unused serum was stored at -80 &#176;C. Prior to testing, the serum was kept at room temperature for 30 min and was shaken with a vortex mixer. Repeated freeze-and-thaw cycles were avoided.
<ol>
	<li>Primarily test the serum samples for sIgEs to whole allergens of Dermatophagoides pteronyssinus (d1), Dermatophagoides farinae (d2), Blomia tropicalis (d201), cat dander (e1), dog dander (e5), Bermuda grass (g2), timothy grass (g6), cockroaches (i6), Aspergillus fumigatus (m3), Candida albicans (m5), ragweed (w1), egg white (f1), milk (f2), wheat (f4), peanut (f13), soybean (f14), almond (f20), crab (f23), and shrimp (f24). Follow the instructions given in section 3. 
	NOTE: sIgE determination was done with the allergen-specific IgE assay kit (see the Table of Materials) and measured by a chemiluminescence analyzer.</li>
	<li>Randomly select three samples from among the samples with enough serum (at least 900 &#181;L) for a reproducibility study. Keeping all the conditions unchanged, measure the three sera for allergen sIgEs daily for 9 consecutive days (i.e., a total of 100 x 9 = 900 &#181;L of serum).</li>
</ol>
3. Semi-automation test procedure of the microfluidic system
NOTE: The System 2 is the integration of automatic microfluidic technology, protein microarray, cold light analysis, parallel IgE analysis, and image processing technology. The testing protocol is divided into four parts: preparation of the equipment, sample loading, incubation, and measurement.
<ol>
	<li>Preparation of the equipment
	<ol>
		<li>Turn on the PC and the analyzer power. 
		NOTE: The power switch is on the left of the base.</li>
		<li>Start the LabIT program on the PC. If the Dark Frame warning window pops up, click OK to run LEAK Test. Afterward, click the center logo to enter the operation interface. 
		NOTE: The system will remind the user to run LEAK Test if it is idle for more than 24 h.</li>
		<li>Check the Reaction Temp and CCD (charge-coupled device) Temp at the lower right corner of the screen. The Reaction Temp should rise to 37 &#176;C &#177; 1 &#176;C in about 10 min, and the CCD Temp should drop to -15 &#176;C &#177; 1 &#176;C.</li>
		<li>Run the LEAK Test after the CCD Temp has dropped to -15 &#176;C &#177; 1 &#176;C. Before running the LEAK test, make sure there are no other items left inside the instrument and close the door. Click Tools | System Test | LEAK Test. Do not open the door during testing. When the test is finished, the report window will pop up.</li>
	</ol>
	</li>
	<li>Sample loading
	<ol>
		<li>Add 620 &#181;L of wash buffer, 120 &#181;L of blocking buffer, 60 &#181;L of conjugates A and B, 60 &#181;L of substrate A and B, and 100 &#181;L of serum samples to the corresponding reagent tank on the microfluidic cartridge.</li>
	</ol>
	</li>
	<li>Incubation
	<ol>
		<li>Click on Cartridge ID, use the barcode scanner to scan the serial number of the cartridge, enter the sample ID, put the cartridge into the analyzer and close the door, and click Analyzer and Run to start the analysis.</li>
	</ol>
	</li>
	<li>Measurement
	<ol>
		<li>Export the results to statistical software (e.g., Excel) after the measurement. 
		NOTE: After 30 min of incubation, the analyzer automatically performs the measurement and reports the result.</li>
	</ol>
	</li>
	<li>Switching off of the analyzer
	<ol>
		<li>For routine maintenance, after finishing the test, remove the cartridge and wipe the analyzer&#8217;s internal heating iron and electromagnet lightly with 75% alcohol. 
		NOTE: Do not press hard or shake the electromagnet.</li>
		<li>Close the LabIT window. The temperature monitoring window will pop up. It will automatically close when the CCD warms up to the 5 &#176;C protection mode. By then, it will be safe to turn off the power of the analyzer and PC. 
		NOTE: Do not manually close the temperature monitoring window before the CCD Temp has risen to 5 &#176;C, and do not turn off the power of the analyzer nor the PC during the CCD warm-up.</li>
	</ol>
	</li>
</ol>
4. Definition of sIgE reactivity
NOTE: For an undiluted serum specimen, the detection range of the System 2 is 0.21&#8211;100 IU/mL.
<ol>
	<li>Based on the threshold value of 0.35 IU/mL, consider an sIgE level exceeding 0.35 IU/mL to be positive6,7. Rate the reactivity of the sIgE tests as8: class 1 (&#8805;0.35 and &#60;0.70 IU/mL), class 2 (&#8805;0.70 and &#60;3.50 IU/mL), class 3 (&#8805;3.50 and &#60;17.50 IU/mL), class 4 (&#8805;17.50 and &#60;50.00 IU/mL), class 5 (&#8805;50.00 and &#60;100.00 IU/mL), and class 6 (&#8805;100.00 IU/mL).</li>
</ol>
5. Statistical analysis
<ol>
	<li>Use a histogram to show the positive rate of the 19 allergens (Figure 1) and use the Levey-Jennings curve to demonstrate the repeatability of the detection system (Figure 2)9.</li>
	<li>Select the three most common inhalant allergens and food allergens (in total, six allergens) and compare the results to the I System 1 to evaluate its clinical diagnostic performance10,11. Include the concordance rate, sensitivity, specificity, positive and negative predictive values, and the area under the receiver operating characteristic (ROC) curve (AUC) as the evaluation criteria.</li>
	<li>Apply Spearman&#8217;s correlation analysis12 to describe correlations between the two systems and use kappa value for consistency. Categorize the kappa value as almost perfect (0.8&#8211;1.0), substantial (0.6&#8211;0.8), moderate (0.4&#8211;0.6), fair (0.2&#8211;0.4), or poor (&#60;0.2)13. Use SPSS 23.0 and MedCalc 11.0 statistical analysis and define P &#60; 0.05 as statistical significance.</li>
</ol>

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H., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Specific+IgE+measurement+using+AdvanSure(R)+system:+comparison+of+detection+performance+with+ImmunoCAP(R)+system+in+Korean+allergy+patients.">Specific IgE measurement using AdvanSure(R) system: comparison of detection performance with ImmunoCAP(R) system in Korean allergy patients.</a> Clinica Chimica Acta. (9-10), 914-919 (2012).</li><li>Eckels, J., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Quality+control,+analysis+and+secure+sharing+of+Luminex(R)+immunoassay+data+using+the+open+source+LabKey+Server+platform.">Quality control, analysis and secure sharing of Luminex(R) immunoassay data using the open source LabKey Server platform.</a> Bmc Bioinformatics. 14 (1), 145 (2013).</li><li>Bland, J. M., Altman, D. 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A., Segall, N., Ahlstedt, S., Williams, P. B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Accuracy+of+IgE+antibody+laboratory+results.">Accuracy of IgE antibody laboratory results.</a> Annals of Allergy Asthma &amp; Immunology. 100 (2), 288-289 (2008).</li><li>Aberer, W., Kr&#228;nke, B., Hager, A., Wick, G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=In+vitro+allergy+testing+needs+better+standardization--test+results+from+different+laboratories+lack+comparability+mostly+due+to+missing+effective+standards.">In vitro allergy testing needs better standardization--test results from different laboratories lack comparability mostly due to missing effective standards.</a> International Archives of Allergy &amp; Immunology. 108 (1), 82-88 (1995).</li></ol>

The authors have nothing to disclose.

Similar to the results from many other studies15,16,17, the results from the microfluidic system based on sera from 293 allergic patients showed that house dust mites (including D. pteronyssinus, D. farinae, and B. tropicalis) are the main inhalant allergens leading to allergic diseases in southern China, whereas for food, milk, peanut, shrimp, and crab are the commonest allergens that cause allergic s...

The prevalence of allergies has increased steadily in the past decades and is affecting 20%-30% of the global population1. Identification of the causative allergens has important significance in managing the diseases. In China, since registered in vivo skin prick tests are not available in the country, in vitro determination of serum-specific IgE is the most important and commonly used tool for type I allergy diagnoses2. This is similar to practices in the Western world, but although ImmunoCAP system (System 1), a fluorescence enzyme-linked immunosorbent base system, is perceived as the gold standard for in vitro allergy diagnosis3, its usage in China is very limited due to its high equipment and reagent price. Hence a new alternative allergy diagnosis system with a high price-performance ratio is badly needed.
The BioIC System (System 2) is a microfluidic cartridge-based system based on the chemiluminescence principle for multiplexed assays of serum-specific IgE. With a size of 7 cm x 4 cm, the microfluidic cartridge is composed of three layers of injection-molded plastic. The upper part is 3 mm-thick transparent polycarbonate which carries good stability during thermal assembly processes. Together with the 3 mm-thick bottom layer constructed from a copolymer of acrylonitrile, butadiene, and styrene (ABS), it sandwiches the 0.5 mm-thick middle layer made of silicone rubber. Being black in color, the middle layer offers lower background during chemiluminescence detection. On top of the silica gel, a thin layer of nitrocellulose membrane (NC membrane) is sprayed at the position corresponding to the reaction zone, which allows the spotting of different allergenic proteins. The purpose of this study is to evaluate the clinical performance of the microfluidic system for the multiplexed determination of allergen-specific IgE in serum.

<table><tbody><tr><td>Agnitio BioIC Analyzer</td><td>Agnitio Science &amp;amp; Technology(Taiwan, China)</td><td>BA-G2000</td><td></td></tr><tr><td>BioIC Allergen specific-IgE Detection Kit</td><td>Agnitio Science &amp;amp; Technology(Taiwan, China)</td><td>DR17A12</td><td></td></tr><tr><td>BioIC Cartrideg Placement plate</td><td>Agnitio Science &amp;amp; Technology(Taiwan, China)</td><td>T20SET</td><td></td></tr><tr><td>BioIC Reagent Dispenser</td><td>Agnitio Science &amp;amp; Technology(Taiwan, China)</td><td>DS-1</td><td></td></tr><tr><td>Image two-dimensional barcode machine</td><td>Agnitio Science &amp;amp; Technology(Taiwan, China)</td><td>NLS-HR200</td><td></td></tr><tr><td>Software Package, LabIT</td><td>Agnitio Science &amp;amp; Technology(Taiwan, China)</td><td>Version 2.4.12</td><td></td></tr><tr><td>VORTEX-5 Vortex Mixer</td><td>Haimen Kylinbell Lab Lastruments Co., Ltd.</td><td>VORTEX-5</td><td></td></tr></tbody></table>

application of biochip microfluidic technology to detect serum allergen-specific immunoglobulin e (sige)

Allergic disease is common in both adults and children. Identification of the causative allergens is significant in disease management and prevention. However, a specific immunoglobulin E (IgE) measurement system with a high price-performance ratio is lacking in mainland China, especially in the primary care hospitals. This paper describes the principle and operation procedures of using a microfluidic cartridge-based chemiluminescence system to detect allergen-specific IgE in serum. The results were compared with those from ImmunoCAP (System 1), the industrial standard, and the reproducibility of the system to detect patients sensitized to common allergens is evaluated. The results showed that in comparison with ImmunoCAP (System 1), the BioIC System (System 2) has good precision and sensitivity in detecting serum-specific IgE against various inhalant and food allergens but with a significantly lower cost. It can serve as a good alternative to System 1 in primary care hospitals in mainland China who have lower financial affordability.

Positive rates for 19 common allergens 
The results on 293 sera are shown in Figure 3. Among all the inhalant allergens, D. farinae had the highest positive rate (80.89%, 273/293), followed by D. pteronyssinus (78.84%, 231/293). Among the food allergens, crab has the highest positive rate (20.48%, 60/293), followed by 13.65% (40/293) for shrimp. The total positive rate for inhalant allergens was higher than tha...

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Application of Biochip Microfluidic Technology to Detect Serum Allergen-specific Immunoglobulin E sIgE

This paper presents a protocol for detecting serum-specific immunoglobulin E with a microfluidic cartridge-based chemiluminescence system and the evaluation of its usefulness in allergy diagnoses.

Application of Biochip Microfluidic Technology to Detect Serum Allergen-specific Immunoglobulin E (sIgE)

Allergic disease is common in both adults and children. Identification of the causative allergens is significant in disease management and prevention. ...

application-biochip-microfluidic-technology-to-detect-serum-allergen

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Medicine

16.3K Views.  First Affiliated Hospital of Guangzhou Medical University, Guangzhou Medical University. This paper presents a protocol for detecting serum-specific immunoglobulin E with a microfluidic cartridge-based chemiluminescence system and the evaluation of its usefulness in allergy diagnoses.

Video: Application of Biochip Microfluidic Technology to Detect Serum Allergen-specific Immunoglobulin E sIgE

A Microfluidic Chip for the Versatile Chemical Analysis of Single Cells

We present a microfluidic device that enables the quantitative determination of intracellular biomolecules in multiple single cells in parallel. For this purpose, the cells are passively trapped in the middle of a microchamber. Upon activation of the control layer, the cell is isolated from the surrounding volume in a small chamber. The surrounding volume can then be exchanged without affecting the isolated cell. However, upon short opening and closing of the chamber, the solution in the chamber can be replaced within a few hundred milliseconds. Due to the reversibility of the chambers, the cells can be exposed to different solutions sequentially in a highly controllable fashion, e.g. for incubation, washing, and finally, cell lysis. The tightly sealed microchambers enable the retention of the lysate, minimize and control the dilution after cell lysis. Since lysis and analysis occur at the same location, high sensitivity is retained because no further dilution or loss of the analytes occurs during transport. The microchamber design therefore enables the reliable and reproducible analysis of very small copy numbers of intracellular molecules (attomoles, zeptomoles) released from individual cells. Furthermore, many microchambers can be arranged in an array format, allowing the analysis of many cells at once, given that suitable optical instruments are used for monitoring. We have already used the platform for proof-of-concept studies to analyze intracellular proteins, enzymes, cofactors and second messengers in either relative or absolute quantifiable manner.

In this article we present a microfluidic chip for single cell analysis. It allows the quantification of intracellular proteins, enzymes, cofactors, and second messengers by means of fluorescent assays or immunoassays.&#160;

We present a microfluidic device that enables the quantitative determination of intracellular biomolecules in multiple single cells in parallel. For this ...

Bioengineering

Profiling Anti-Neu5Gc IgG in Human Sera with a Sialoglycan Microarray Assay

Cells are covered with a cloak of carbohydrate chains (glycans) that is commonly altered in cancer and that includes variations in sialic acid (Sia) expression. These are acidic sugars that have a 9-carbon backbone and that cap vertebrate glycans on cell surfaces. Two of the major Sia forms in mammals are N-acetylneuraminic acid (Neu5Ac) and its hydroxylated form, N-glycolylneuraminic acid (Neu5Gc). Humans cannot produce endogenous Neu5Gc due to the inactivation of the gene encoding cytidine 5&#39;monophosphate-Neu5Ac (CMP-Neu5Ac) hydroxylase (CMAH). Foreign Neu5Gc is acquired by human cells through the dietary consumption of red meat and dairy and subsequently appears on diverse glycans on the cell surface, accumulating mostly on carcinomas. Consequently, humans have circulating anti-Neu5Gc antibodies that play diverse roles in cancer and other chronic inflammation-mediated diseases and that are becoming potential diagnostic and therapeutic targets. Here, we describe a high-throughput sialoglycan microarray assay to assess such anti-Neu5Gc antibodies in the human sera. Neu5Gc-containing glycans and their matched pairs of controls (Neu5Ac-containing glycans), each with a core primary amine, are covalently linked to epoxy-coated glass slides. We exemplify the printing of 56 slides in a 16-well format using a specific nano-printer capable of generating up to 896 arrays per print. Each slide can be used to screen 16 different human sera samples for the evaluation of anti-Neu5Gc antibody specificity, intensity, and diversity. The protocol describes the complexity of this robust tool and provides a basic guideline for those aiming to investigate the response to Neu5Gc dietary carbohydrate antigen in diverse clinical samples in an array format.

A sialoglycan microarray assay can be used to evaluate anti-Neu5Gc antibodies in human sera, making it a potential high-throughput diagnostic assay for cancer and other chronic inflammation-mediated human diseases.

Cells are covered with a cloak of carbohydrate chains (glycans) that is commonly altered in cancer and that includes variations in sialic acid (Sia) ...

Behavior

A Microfluidic-based Electrochemical Biochip for Label-free DNA Hybridization Analysis

Miniaturization of analytical benchtop procedures into the micro-scale provides significant advantages in regards to reaction time, cost, and integration of pre-processing steps. Utilizing these devices towards the analysis of DNA hybridization events is important because it offers a technology for real time assessment of biomarkers at the point-of-care for various diseases. However, when the device footprint decreases the dominance of various physical phenomena increases. These phenomena influence the fabrication precision and operation reliability of the device. Therefore, there is a great need to accurately fabricate and operate these devices in a reproducible manner in order to improve the overall performance. Here, we describe the protocols and the methods used for the fabrication and the operation of a microfluidic-based electrochemical biochip for accurate analysis of DNA hybridization events. The biochip is composed of two parts: a microfluidic chip with three parallel micro-channels made of polydimethylsiloxane (PDMS), and a 3 x 3 arrayed electrochemical micro-chip. The DNA hybridization events are detected using electrochemical impedance spectroscopy (EIS) analysis. The EIS analysis enables monitoring variations of the properties of the electrochemical system that are dominant at these length scales. With the ability to monitor changes of both charge transfer and diffusional resistance with the biosensor, we demonstrate the selectivity to complementary ssDNA targets, a calculated detection limit of 3.8 nM, and a 13% cross-reactivity with other non-complementary ssDNA following 20 min&#160;of incubation. This methodology can improve the performance of miniaturized devices by elucidating on the behavior of diffusion at the micro-scale regime and by enabling the study of DNA hybridization events.

We present a microfluidic-based electrochemical biochip for DNA hybridization detection. Following ssDNA probe functionalization, the specificity, sensitivity, and detection limit are studied with complementary and non-complementary ssDNA targets. Results illustrate the influence of the DNA hybridization events on the electrochemical system, with a detection limit of 3.8 nM.

Miniaturization of analytical benchtop procedures into the micro-scale provides significant advantages in regards to reaction time, cost, and integration ...

Generation of Two-color Antigen Microarrays for the Simultaneous Detection of IgG and IgM Autoantibodies

Autoantibodies, which are antibodies against self-antigens, are present in many disease states and can serve as markers for disease activity. The levels of autoantibodies to specific antigens are typically detected with the enzyme-linked immunosorbent assay (ELISA) technique. However, screening for multiple autoantibodies with ELISA can be time-consuming and requires a large quantity of patient sample. The antigen microarray technique is an alternative method that can be used to screen for autoantibodies in a multiplex fashion. In this technique, antigens are arrayed onto specially coated microscope slides with a robotic microarrayer. The slides are probed with patient serum samples and subsequently fluorescent-labeled secondary antibodies are added to detect binding of serum autoantibodies to the antigens. The autoantibody reactivities are revealed and quantified by scanning the slides with a scanner that can detect fluorescent signals. Here we describe methods to generate custom antigen microarrays. Our current arrays are printed with 9 solid pins and can include up to 162 antigens spotted in duplicate. The arrays can be easily customized by changing the antigens in the source plate that is used by the microarrayer. We have developed a two-color secondary antibody detection scheme that can distinguish IgG and IgM reactivities on the same slide surface. The detection system has been optimized to study binding of human and murine autoantibodies.

We describe here a method to generate customizable antigen microarrays that can be used for the simultaneous detection of serum IgG and IgM autoantibodies from humans and mice. These arrays allow for high-throughput and quantitative detection of antibodies against any antigens or epitopes of interest.

Autoantibodies, which are antibodies against self-antigens, are present in many disease states and can serve as markers for disease activity. The levels ...

Immunology and Infection

Snap Chip for Cross-reactivity-free and Spotter-free Multiplexed Sandwich Immunoassays

Multiplexed protein analysis has shown superior diagnostic sensitivity and accuracy compared to single proteins. Antibody microarrays allow for thousands of micro-scale immunoassays performed simultaneously on a single chip. Sandwich assay format improves assay specificity by detecting each target with two antibodies, but suffers from cross-reactivity between reagents thus limiting their multiplexing capabilities. Antibody colocalization microarray (ACM) has been developed for cross-reactivity-free multiplexed protein detection, but requires an expensive spotter on-site for microarray fabrication during assays. In this work, we demonstrate a snap chip technology that transfers reagent from microarray-to-microarray by simply snapping two chips together, thus no spotter is needed during the sample incubation and subsequent application of detection antibodies (dAbs) upon storage of pre-spotted slides, dissociating the slide preparation from assay execution. Both single and double transfer methods are presented to achieve accurate alignment between the two microarrays and the slide fabrication for both methods are described. Results show that &#60;40 &#956;m alignment has been achieved with double transfer, reaching an array density of 625 spots/cm2. A 50-plexed immunoassay has been conducted to demonstrate the usability of the snap chip in multiplexed protein analysis. Limits of detection of 35 proteins are in the range of pg/mL.

We demonstrate a snap chip technology for performing cross-reactivity-free multiplexed sandwich immunoassays by simply snapping two slides. A snap apparatus is used for reliably transferring reagents from microarray-to-microarray. The snap chip can be used for any biochemical reactions requiring colocalization of different reagents without cross-contamination.

Multiplexed protein analysis has shown superior diagnostic sensitivity and accuracy compared to single proteins. Antibody microarrays allow for thousands ...

Printed Glycan Array: A Sensitive Technique for the Analysis of the Repertoire of Circulating Anti-carbohydrate Antibodies in Small Animals

The repertoire of circulating anti-carbohydrate antibodies of a given individual is often associated with its immunological status. Not only the individual immune condition determines the success in combating internal and external potential threat signals, but also the existence of a particular pattern of circulating anti-glycan antibodies (and their serological level variation) could be a significant marker of the onset and progression of certain pathological conditions. Here, we describe a Printed Glycan Array (PGA)-based methodology that offers the opportunity to measure hundreds of glycan targets with very high sensitivity; using a minimal amount of sample, which is a common restriction present when small animals (rats, mice, hamster, etc.) are used as models to address aspects of human diseases. As a representative example of this approach, we show the results obtained from the analysis of the repertoire of natural anti-glycan antibodies in BALB/c mice. We demonstrate that each BALB/c mouse involved in the study, despite being genetically identical and maintained under the same conditions, develops a particular pattern of natural anti-carbohydrate antibodies. This work claims to expand the use of PGA technology to investigate repertoire (specificities) and the levels of circulating anti-carbohydrates antibodies, both in health and during any pathological condition.

This work shows the potential of printed glycan array (PGA) technology for the analysis of circulating anti-carbohydrate antibodies in small animals.

The repertoire of circulating anti-carbohydrate antibodies of a given individual is often associated with its immunological status. Not only the ...

Characterization of Thymus-dependent and Thymus-independent Immunoglobulin Isotype Responses in Mice Using Enzyme-linked Immunosorbent Assay

Antibodies, also termed as immunoglobulins (Ig), secreted by differentiated B lymphocytes, plasmablasts/plasma cells, in humoral immunity provide a formidable defense against invading pathogens via diverse mechanisms. One major goal of vaccination is to induce protective antigen-specific antibodies to prevent life-threatening infections. Both thymus-dependent (TD) and thymus-independent (TI) antigens can elicit robust antigen-specific IgM responses and can also induce the production of isotype-switched antibodies (IgG, IgA and IgE) as well as the generation of memory B cells with the help provided by antigen presenting cells (APCs). Here, we describe a protocol to characterize TD and TI Ig isotype responses in mice using enzyme-linked immunosorbent assay (ELISA). In this protocol, TD and TI Ig responses are elicited in mice by intraperitoneal (i.p.) immunization with hapten-conjugated model antigens TNP-KLH (in alum) and TNP-polysaccharide (in PBS), respectively. To induce TD memory response, a booster immunization of TNP-KLH in alum is given at 3 weeks after the first immunization with the same antigen/adjuvant. Mouse sera are harvested at different time points before and after immunization. Total serum Ig levels and TNP-specific antibodies are subsequently quantified using Ig isotype-specific Sandwich and indirect ELISA, respectively. In order to correctly quantify the serum concentration of each Ig isotype, the samples need to be appropriately diluted to fit within the linear range of the standard curves. Using this protocol, we have consistently obtained reliable results with high specificity and sensitivity. When used in combination with other complementary methods such as flow cytometry, in vitro culture of splenic B cells and immunohistochemical staining (IHC), this protocol will allow researchers to gain a comprehensive understanding of antibody responses in a given experimental setting.

In this paper, we describe a protocol to characterize T-dependent and T-independent immunoglobulin (Ig) isotype responses in mice using ELISA. This method used alone or in combination with flow cytometry will allow researchers to identify differences in B cell-mediated Ig isotype responses in mice following T-dependent and T-independent antigen immunization.

Antibodies, also termed as immunoglobulins (Ig), secreted by differentiated B lymphocytes, plasmablasts/plasma cells, in humoral immunity provide a ...

Electrowetting-based Digital Microfluidics Platform for Automated Enzyme-linked Immunosorbent Assay

Electrowetting is the effect by which the contact angle of a droplet exposed to a surface charge is modified. Electrowetting-on-dielectric (EWOD) exploits the dielectric properties of thin insulator films to enhance the charge density and hence boost the electrowetting effect. The presence of charges results in an electrically induced spreading of the droplet which permits purposeful manipulation across a hydrophobic surface. Here, we demonstrate EWOD-based protocol for sample processing and detection of four categories of antigens, using an automated surface actuation platform, via two variations of an Enzyme-Linked Immunosorbent Assay (ELISA) methods. The ELISA is performed on magnetic beads with immobilized primary antibodies which can be selected to target a specific antigen. An antibody conjugated to HRP binds to the antigen and is mixed with H2O2/Luminol for quantification of the captured pathogens. Assay completion times of between 6 and 10 min were achieved, whilst minuscule volumes of reagents were utilized.

Electrowetting-based digital microfluidic is a technique that utilizes a voltage-driven change in the apparent contact angle of a microliter-volume droplet to facilitate its manipulation. Combining this with functionalized magnetic beads enables the integration of multiple laboratory unit operations for sample preparation and identification of pathogens using Enzyme-linked Immunosorbent Assay (ELISA).

Electrowetting is the effect by which the contact angle of a droplet exposed to a surface charge is modified. Electrowetting-on-dielectric (EWOD) exploits ...

An Assay to Detect Serum Anti-aquaporin-4 Immunoglobulin G

Source: Liu, C. et al., <a href="https://app.jove.com/v/59014">Human Serum Anti-aquaporin-4 Immunoglobulin G Detection by Cell-based Assay.</a>&#160;J. Vis. Exp.&#160;(2019)
The video demonstrates a cell-based assay for detecting anti-aquaporin-4 immunoglobulin G using a biochip containing untransfected cells and transfected cells expressing aquaporin-4. This method has applications in diagnosing neuromyelitis optica spectrum disorders, confirmed by strong green fluorescence on the biochip.

Test do wykrywania immunoglobuliny G antyakwaporyny-4 w surowicy

All procedures involving human participants have been performed in compliance with the institutional, national, and international guidelines for human ...

JoVE Encyclopedia of Experiments

Immunology

Antibody-Based Technologies

Characterization and Functional Analysis

A Microfluidic Cartridge-Based Detection System for Allergen-Specific Immunoglobulin E

Source: Huang, Z., et al. <a href="https://app.jove.com/v/59100">Application of Biochip Microfluidic Technology to Detect Serum Allergen-specific Immunoglobulin E (sIgE).</a>&#160;J. Vis. Exp.&#160;(2019)
This video demonstrates a protocol for detecting serum-specific immunoglobulin E using a microfluidic cartridge-based chemiluminescence system. Serum IgEs interact with distinct allergens immobilized in the reaction zone of the cartridge, which are subsequently detected with peroxidase-conjugated anti-IgE antibodies and a chemiluminescent substrate, allowing simultaneous detection of multiple allergen-specific IgEs.

Oparty na kartridżu mikroprzepływowym system wykrywania swoistej dla alergenu E immunoglobuliny E

All procedures involving sample collection have been performed in accordance with the institute&#39;s IRB guidelines.
1. Basic information of the study ...