We thank Cassandra Bryant for performing the IIF experiment and Carol Buchner for her expert technical review.

1. Sample Preparation and Substrate Selection
<ol>
	<li>Remove reagents from packaging and allow each item to come to room temperature. Prepare reagents and dilute patient sera according to the direction insert. Note: NOVA Lite slides are barcoded and can be easily integrated into automated systems in conjunction with the Laboratory Information System LIS. This procedure illustrates manual slide processing; high throughput laboratories, however, may opt for automated slide processing equipment.</li>
</ol>
2. Addition of Controls and Samples
<ol>
	<li>Dispense 1 drop of positive control and 1 drop of negative control to the appropriate slide wells.&#160;Pipette 20-25 &#956;l of diluted patient serum to the remaining wells. Process one slide at a time.</li>
	<li>Place the slide(s) in a staining container with a damp paper towel on the bottom.&#160;Cover the container and incubate the slide(s) for 30 min. Note: The humid conditions will prevent the substrate from drying out. Drying of the wells could result in artifactual staining. During this incubation period, the anti-nuclear antibodies in the patient&#8217;s serum will bind to antigens of the cells that are fixed onto each well.</li>
	<li>After the incubation period, rinse off the serum using a gentle stream of wash buffer.&#160;In order to avoid damaging the substrate and prevent cross-over of samples between wells, angle the slide slightly to avoid directing the stream directly onto the wells. Tap off excess wash buffer and place the slide into a Coplin jar containing wash buffer for approximately 5 min.</li>
</ol>
3. Addition of Fluorescent Conjugate
<ol>
	<li>One by one, remove the slides from the wash buffer and gently tap to remove the excess wash buffer. Apply 1 drop of fluorescent conjugate (FITC labeled anti-human IgG) onto each well. Incubate the slides for 30 min in the humidified container, and be sure to replace the staining container cover. Note: For ANA testing, the use of an IgG Fc specific conjugate is recommended. The conjugate is light sensitive, and the cover will protect the slides from exposure to light in addition to maintaining the humidified environment. During this incubation period, the conjugate will bind to the patient&#8217;s anti-nuclear antibodies that have bound to the cell antigens. This conjugate binding results in the presence of fluorescence in the wells.</li>
	<li>Rinse and wash the slide as described above.</li>
	<li>Place a coverslip on a paper towel and apply mounting medium in a continuous line to the bottom edge of the coverslip.</li>
	<li>Remove each slide from the wash buffer and tap the slide gently to remove the excess wash buffer. Touch the lower edge of the slide to the edge of the coverslip.</li>
	<li>Gently lower the slide onto the coverslip in such a way that the mounting medium on the coverslip flows to the top edge of the slide without air bubble formation. Note: Coverslipping, including using the optimal amount of mounting medium, is a technique that takes practice to perfect.</li>
</ol>
4. Identification of Positive and Negative Results
Manual Interpretation
<ol>
	<li>View slides with a fluorescent microscope, located in a dark room. Perform scanning of the entire well with a 20X or 25X objective to assess cell distribution and uniformity of fluorescence</li>
	<li>Switch to a 40X objective to make the final interpretation regarding positivity and pattern.</li>
	<li>Look at the positive and negative controls. Grade positivity using a reactivity grading scale from 1+ to 4+. Note: The negative control may not appear completely dark, but will often display low level nonspecific fluorescence. The positive control will display bright apple green fluorescence in the nucleus (Figure 1).</li>
</ol>
Automated Interpretation
Note: In addition to manual interpretation, load and scan slides by NOVA View Automated Fluorescence Microscope or other automated digital imaging instrument; no darkroom is necessary. After creating a project by selecting the appropriate slide type, the instrument acquires and stores high resolution digital images of cells in each well. Additionally, NOVA View measures fluorescent light intensity, and categorizes results as positive or negative, and provides pattern recognition for positive samples. Images are viewed by the operator on a high resolution computer monitor, allowing for final interpretation, revision and confirmation of NOVA View result. Reports can be generated on confirmed results. Digital microscopy should be used in conjunction with an experienced laboratory technician as it is intended to aid in interpretation of results.

<ol>
	<li>Meroni, P. L., Schur, P. H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=ANA+screening:+an+old+test+with+new+recommendations.">ANA screening: an old test with new recommendations.</a> Ann Rheum Dis. 69 (8), 1420-1422 (2010).</li><li>Tan, E. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Autoantibodies+to+nuclear+antigens+(ANA):+Their+immunobiology+and+medicine.">Autoantibodies to nuclear antigens (ANA): Their immunobiology and medicine.</a> Advances in immunology. 33, 167-240 (1982).</li><li>Sack, U., 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=Autoantibody+detection+using+indirect+immunofluorescence+on+HEp-2+cells.">Autoantibody detection using indirect immunofluorescence on HEp-2 cells.</a> Ann NY Acad Sci. 1173, 166-173 (2009).</li><li>Watanabe, A., 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=Anti-DFS70+antibodies+in+597+healthy+hospital+workers.">Anti-DFS70 antibodies in 597 healthy hospital workers.</a> Arthritis Rheum. 50 (3), 892-900 (2004).</li><li>Mahler, M., 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=Importance+of+the+dense+fine+speckled+pattern+on+HEp-2+cells+and+anti-DFS70+antibodies+for+the+diagnosis+of+systemic+autoimmune+diseases.">Importance of the dense fine speckled pattern on HEp-2 cells and anti-DFS70 antibodies for the diagnosis of systemic autoimmune diseases.</a> Autoimmun Revi. 11 (9), 642-645 (2012).</li><li>Mahler, M., Fritzler, M. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+clinical+significance+of+the+dense+fine+speckled+immunofluorescence+pattern+on+HEp-2+cells+for+the+diagnosis+of+systemic+autoimmune+diseases.">The clinical significance of the dense fine speckled immunofluorescence pattern on HEp-2 cells for the diagnosis of systemic autoimmune diseases.</a> Clin Dev Immunol. , (2012).</li><li>Miyara, M., 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=Clinical+phenotypes+of+patients+with+anti-DFS70/LEDGF+antibodies+in+a+routine+ANA+referral+cohort.">Clinical phenotypes of patients with anti-DFS70/LEDGF antibodies in a routine ANA referral cohort.</a> Clin Dev Immunol. , (2013).</li><li>Mariz, 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=Pattern+on+the+antinuclear+antibody-HEp-2+test+is+a+critical+parameter+for+discriminating+antinuclear+antibody+positive+healthy+individuals+and+patients+with+autoimmune+rheumatic+diseases.">Pattern on the antinuclear antibody-HEp-2 test is a critical parameter for discriminating antinuclear antibody positive healthy individuals and patients with autoimmune rheumatic diseases.</a> Arthritis Rheum. 63 (1), 191-200 (2011).</li><li>Muro, Y., 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=High+concomitance+of+disease+marker+autoantibodies+in+anti-DFS70/LEDGF+autoantibody-positive+patients+with+autoimmune+rheumatic+disease.">High concomitance of disease marker autoantibodies in anti-DFS70/LEDGF autoantibody-positive patients with autoimmune rheumatic disease.</a> Lupus. 17 (3), 171-176 (2008).</li><li>Agmon-Levin, N., 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=International+recommendations+for+the+assessment+of+autoantibodies+to+cellular+antigens+referred+to+as+anti-nuclear+antibodies.">International recommendations for the assessment of autoantibodies to cellular antigens referred to as anti-nuclear antibodies.</a> Ann Rheum Dis. 73 (1), 17-23 (2014).</li><li>Craft, 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=The+U2+small+nuclear+ribonucleoprotein+particle+as+an+autoantigen.">The U2 small nuclear ribonucleoprotein particle as an autoantigen.</a> J Clin Invest. 81 (6), 1716-1724 (1998).</li><li>Salomonsson, S., 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=A+serologic+marker+for+fetal+risk+of+congenital+heart+block.">A serologic marker for fetal risk of congenital heart block.</a> Arthritis Rheum. 46 (5), 1233-1241 (2002).</li><li>Miyawaki, S., 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=Clinical+and+serological+heterogeneity+in+patients+with+anticentromere+antibodies.">Clinical and serological heterogeneity in patients with anticentromere antibodies.</a> J Rheumatology. 32 (8), 1488-1494 (2005).</li><li>Raijamkers, R., 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=PM-Scl-75+is+the+main+autoantigen+in+patients+with+the+polymyositis/scleroderma+overlap+syndrome.">PM-Scl-75 is the main autoantigen in patients with the polymyositis/scleroderma overlap syndrome.</a> Arthritis Rheum. 50 (2), 565-569 (2004).</li><li>Yang, J. M., 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=Human+scleroderma+sera+contain+autoantibodies+to+protein+components+specific+to+the+UC+small+nucleolar+RNP+complex.">Human scleroderma sera contain autoantibodies to protein components specific to the UC small nucleolar RNP complex.</a> Arthritis Rheum. 48 (1), 210-217 (2003).</li><li>Granito, A., 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=Antinuclear+antibodies+as+ancillary+markers+in+primary+biliary+cirrhosis.">Antinuclear antibodies as ancillary markers in primary biliary cirrhosis.</a> Expert Rev Mol Diagn. 12 (1), 65-74 (2012).</li></ol>

The authors Gabriella Lakos, Cassandra Bryant, Carol Buchner, and Anna Eslami are employees of INOVA Diagnostics.

Screening by HEp-2 cells is a critical first step in the diagnosis of patients with SARD. However, IIF methods lack harmonization. Sources of variability include preparation of slides, conjugate specificity, and efficiency of the fluorescent microscope and experience of the reader. Despite these concerns, IIF remains the &#8220;gold standard&#8221; for ANA testing. HEp-2 cells contain a large variety of autoantigens, and provide the ideal substrate for the detection of these autoantibodies. In some laboratories, IIF has been replaced with solid phase screening methods such as multiplex assay or ELISA. The shortcoming of such tests is that they do not display the full range of antigens to be sufficiently sensitive. As a consequence, true positive patients may be missed which can have deleterious consequences In addition to the issues of treatment delay and wrong diagnosis, additional healthcare costs may occur due to the repetition of confirmatory tests or unnecessary diagnostic investigations. Given the inherent challenges to IIF, it is paramount to perform this technique properly to avoid subjectivity in results.
To ensure accurate interpretation and reporting of results for ANA screening, it is vital to use the highest quality substrate. When selecting a HEp-2 substrate, it is critical that the cells be optimized to express clinically relevant epitopes in their native protein state. Transfected or otherwise modified HEp-2 cell lines may not allow proper antibody-antigen binding. In addition, when several different autoantibodies are present simultaneously, recombinant cells may mask one or more patterns. High number of mitotic cells should also be present in the substrate. Adequate number of mitotic cells allows quick and accurate identification of patterns. 
In addition to the attributes of the substrate, the objective of this video protocol is to describe the IIF technique by showing critical steps such as the addition of sample, slide washing, addition of conjugate, cover slipping, and determination of positive and negative results. Results can be compromised if proper technique is not used for each of these steps. Proper washing is important to remove all unbound antibody. Some patients display very high amounts of autoantibodies and in these cases it is important to wash the serum from the wells such that it does not contaminate other wells. 
Although IIF has traditionally been a very labor intensive and subjective laboratory method, new technologies such as slide processors, barcoded slides and automated digital microscopy can greatly simplify the workflow, increase the consistency and reduce the sources of variability of interpretation.

The term antinuclear antibody (ANA) describes a variety of autoantibodies that react with constituents of cell nuclei including DNA, proteins and ribonucleoproteins1,2. The HEp-2 cell, a native protein array with hundreds of antigens, provides an ideal substrate for the detection of ANA1. The detection of ANA in human serum is an important screening tool for connective tissue diseases, and IIF is the reference method for ANA testing1. Recently, IIF on HEp-2 cells has been replaced in some laboratories with antigen-specific immunoassays and multiplex methods. Due to concerns over false negative results and the lack of transparency to clinicians, the American College of Rheumatology formed a Task Force that concluded that IIF using HEp-2 cells should be the &#8220;gold standard&#8221; for ANA screening1.
Due to the subjective nature of ANA screening, the quality of HEp-2 cells is integral to accurate and confident reporting of results. The presence of a high number of mitotic cells, optimal cell morphology, sufficient confluency, and expression of relevant antigens are particularly important. IIF pattern recognition serves as an important tool to aid in patient diagnosis. Understanding the significance of various patterns enables the clinicians and laboratory personnel to perform the appropriate follow-up testing to confirm diagnosis. For example, homogeneous ANA pattern can occur in the presence of anti-dsDNA or chromatin antibodies, and may be associated with systemic lupus erythematosus (SLE)3. From the other side, it has recently been described that the so called dense fine speckled pattern (DFS) that is commonly seen in up to 12% of routine samples, has mostly been associated with anti-DFS70 antibodies. These autoantibodies, when found in isolation (without other disease-specific ANA) are not associated with systemic autoimmune rheumatic diseases4-9. Thereby confirmatory testing for anti-DFS70 antibodies can help reduce unnecessary reflex testing, offer considerable cost savings, and ease patient anxiety.
Given that IIF is the first line screening methodology to detect autoantibodies, it is paramount that the user understands how the selection of reagents and tissue substrates can affect results. Since the IIF technique is inherently subjective, it is important that the reagents used provide the highest quality results.
This goal of this video protocol is to familiarize the user with the correct steps needed to perform the IIF method, the common patterns associated with ANA, and to introduce new advancements which can streamline the laboratory workflow and standardize results.

<table border="0" cellpadding="0" cellspacing="0" width="753">
	<tbody>
		<tr height="20">
			<td height="20" style="height:20px;width:252px;">NOVA Lite HEp-2 IgG (DAPI conjugate)</td>
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</table>

anti-nuclear antibody screening using hep-2 cells

The American College of Rheumatology position statement on ANA testing stipulates the use of IIF as the gold standard method for ANA screening1. Although IIF is an excellent screening test in expert hands, the technical difficulties of processing and reading IIF slides &#8211; such as the labor intensive slide processing, manual reading, the need for experienced, trained technologists and the use of dark room &#8211; make the IIF method difficult to fit in the workflow of modern, automated laboratories.
The first and crucial step towards high quality ANA screening is careful slide processing. This procedure is labor intensive, and requires full understanding of the process, as well as attention to details and experience.
Slide reading is performed by fluorescent microscopy in dark rooms, and is done by trained technologists who are familiar with the various patterns, in the context of cell cycle and the morphology of interphase and dividing cells. Provided that IIF is the first line screening tool for SARD, understanding the steps to correctly perform this technique is critical.
Recently, digital imaging systems have been developed for the automated reading of IIF slides. These systems, such as the NOVA View Automated Fluorescent Microscope, are designed to streamline the routine IIF workflow. NOVA View acquires and stores high resolution digital images of the wells, thereby separating image acquisition from interpretation; images are viewed an interpreted on high resolution computer monitors. It stores images for future reference and supports the operator&#8217;s interpretation by providing fluorescent light intensity data on the images. It also preliminarily categorizes results as positive or negative, and provides pattern recognition for positive samples. In summary, it eliminates the need for darkroom, and automates and streamlines the IIF reading/interpretation workflow. Most importantly, it increases consistency between readers and readings. Moreover, with the use of barcoded slides, transcription errors are eliminated by providing sample traceability and positive patient identification. This results in increased patient data integrity and safety.
The overall goal of this video is to demonstrate the IIF procedure, including slide processing, identification of common IIF patterns, and the introduction of new advancements to simplify and harmonize this technique.

When evaluating cell staining results for HEp-2, five major nuclear patterns are most commonly reported: homogenous, speckled, centromere, nucleolar, and nuclear dots. These patterns are the result of autoantibody binding to specific constituents of the nucleus. Although ANA testing is specific to nuclear structures, cytoplasmic patterns associated with autoantibodies against cytoplasmic structures may also be observed. In some cases, several autoantibodies may be present in a sample, and the image may appear as a mixed pattern.
There are other, less frequently observed, and often cell cycle specific patterns that can be detected by the IIF method; most recently, a so called dense fine speckled pattern with special clinical significance has been described in some ANA positive sera.
Homogeneous Pattern
To identify a homogeneous pattern, scan the well and identify mitotic or dividing cells. The condensed chromatin of the mitotic cells (Figure 2, orange arrow) exhibits solid, uniform fluorescence which is often more pronounced than in the resting cell nuclei.In the homogeneous pattern, the resting cells exhibit uniform, diffuse fluorescence of the entire nucleus (Figure 2, white arrow). This characteristic pattern is often the result of anti-dsDNA antibodies10.
Speckled Pattern
In the coarse speckled pattern, the mitotic cells show no staining of the condensed chromosomal regions (Figure 3, orange arrow). The resting cells exhibit granular fluorescence throughout the entire nucleus. The nuclear speckling can be defined as coarse or fine. The Coarse speckling pattern is often the result of anti-Sm and anti-RNP11.
In the fine speckled pattern, the resting cells show fine or diffuse speckling throughout the nuclei, typically in uniform distribution (Figure 4, white arrow). The fine speckled pattern is often the result of anti-SSAand anti-SSB12.
Dense Fine Speckled Pattern
It is now recognized that the dense fine speckled pattern (DFS) is common in routine testing, and as much as 12% of samples are positive for anti-DFS70 autoantibodies. However, these autoantibodies, when found in isolation, are not associated with systemic autoimmune rheumatic diseases4-6. These antibodies are prevalent in healthy individuals and patients bearing diseases unrelated to SARD6. Confirmatory testing for anti-DFS70 antibodies can help reduce unnecessary reflex testing, offer considerable cost savings, and ease patient anxiety.
Since the DFS pattern is difficult to identify and ANA positivity can cause anxiety to both patients and physicians, it is highly recommended to perform a confirmatory test after identifying a pattern suggestive of anti-DFS70 antibodies to clarify the clinical significance of ANA positivty5,6.
In this pattern, mitotic cells (Figure 5, orange arrow) show positive speckled staining of the metaphase chromatin, while resting cell nuclei (Figure 5, white arrow) exhibit uniformly distributed fine speckles throughout the nucleus.

Centromere Pattern
To identify the centromere pattern, scan the wells and identify mitotic or dividing cells. In mitotic cells (Figure 6, orange arrow), these discrete speckles become closely associated in what is often described as a &#8220;metaphase bar&#8221;. In the centromere pattern, resting cells (Figure 6, white arrow) show approximately 40-60 discrete speckles distributed throughout the nuclei. The centromere pattern is the result of anti-CENP A,B,C antibodies13.
Nucleolar Pattern
Some nucleolar patterns are associated with diffuse cytoplasmic staining in mitotic cells (Figure 7, orange arrow) and negative chromosomal region, while other nucleolear patterns display positive staining of the chromosomal region. The nucleolar pattern is associated with homogenous or speckled staining of the nucleoli (Figure 7, white arrow), along with weak speckled or homogenous staining of the nucleoplasm. These patterns are associated with anti-RNA polymerase III, anti-fibrillarin, anti-Th/To and anti-PM/Scl antibodies14,15.
Nuclear Dot Pattern
The nuclear dot pattern is associated with negative metaphase mitotic cells (Figure 8, orange arrow)and with few discrete speckles in the resting cell nuclei (Figure 8, white arrow). This characteristic pattern is often the result of sp-100, PML, or p80 colin autoantibodies. These antibodies are associated with primary biliary cirrhosis and autoimmune hepatitis16.
<img alt="Figure 1" fo:content-width="5in" src="/files/ftp_upload/51211/51211fig1highres.jpg" width="500" /> 
Figure 1. Negative control (left): Cells display low level non-specific fluorescence, but no specific nuclear staining. Positive control (right): Cells display apple green nuclear fluorescence.
<img alt="Figure 2" fo:content-width="5in" src="/files/ftp_upload/51211/51211fig2highres.jpg" width="500" /> 
Figure 2. Homogenous pattern. Mitotic cells (orangearrow) show solid fluorescence. Resting cells show even, diffuse staining (whitearrow).
<img alt="Figure 3" fo:content-width="5in" src="/files/ftp_upload/51211/51211fig3highres.jpg" width="500" /> 
Figure 3. Coarse speckled pattern. Mitotic cells (orange arrow) show negative staining. Resting cells show a distinct speckled stain (white arrow).
<img alt="Figure 4" fo:content-width="5in" src="/files/ftp_upload/51211/51211fig4highres.jpg" width="500" /> 
Figure 4. Fine speckled pattern. Mitotic cells (orange arrow) show negative staining. Resting cells show a distinct fine speckled staining (white arrow).
<img alt="Figure 5" fo:content-width="5in" src="/files/ftp_upload/51211/51211fig5highres.jpg" width="500" /> 
Figure 5. Dense fine speckled pattern. Mitotic cells (orange arrow) show a fine granular solid staining. Resting cells show a very fine, diffuse speckled stain (whitearrow).
<img alt="Figure 6" fo:content-width="5in" src="/files/ftp_upload/51211/51211fig6highres.jpg" width="500" /> 
Figure 6. Centromere pattern. Mitotic cells (orangearrow) show uniform, discrete speckles. Resting cells (whitearrow) shows 40-60 discrete speckles per cell nucleus.
<img alt="Figure 7" fo:content-width="5in" src="/files/ftp_upload/51211/51211fig7highres.jpg" width="500" /> 
Figure 7. Nucleolar pattern. Mitotic cells (orangearrow) appear as large clusters of granular staining. Resting cell nucleishows fluorescence in the nucleoli(whitearrow).
<img alt="Figure 8" fo:content-width="5in" src="/files/ftp_upload/51211/51211fig8highres.jpg" width="500" /> 
Figure 8. Nuclear dot pattern. Mitotic cells (orangearrow) appear negative. Resting cells show a few discrete speckles in the nucleus (whitearrow).Additionally, the nucelar dot pattern can coexist with cytoplasmic staining associated with autoantibodies to mitochondrial antigens (red arrow).

Watch this Scientific Journal Video about Anti-Nuclear Antibody Screening Using HEp-2 Cells at JoVE.com

Anti-Nuclear Antibody Screening Using HEp-2 Cells

Indirect immunofluorescent (IIF) assays have traditionally been used for the detection of antinuclear antibodies (ANA) in human serum. The presence of these antibodies can aid in the diagnosis of systemic autoimmune rheumatic diseases (SARD). This protocol demonstrates how to effectively perform the IIF technique to accurately detect these autoantibodies.

The American College of Rheumatology position statement on ANA testing stipulates the use of IIF as the gold standard method for ANA screening1. Although ...

anti-nuclear-antibody-screening-using-hep-2-cells

Research

JoVE Journal

Biology

133.7K Views.  INOVA Diagnostics, Inc.. Indirect immunofluorescent (IIF) assays have traditionally been used for the detection of antinuclear antibodies (ANA) in human serum. The presence of these antibodies can aid in the diagnosis of systemic autoimmune rheumatic diseases (SARD). This protocol demonstrates how to effectively perform the IIF technique to accurately detect these autoantibodies.

Video: Anti-Nuclear Antibody Screening Using HEp-2 Cells

Live Dissection of Drosophila Embryos: Streamlined Methods for Screening Mutant Collections by Antibody Staining

Drosophila embryos between stages 14 and 17 of embryonic development can be readily dissected to generate "fillet" preparations. In these preparations, the central nervous system runs down the middle, and is flanked by the body walls. Many different phenotypes have been examined using such preparations. In most cases, the fillets were generated by dissection of antibody-stained fixed whole-mount embryos. These "fixed dissections" have some disadvantages, however. They are time-consuming to execute, and it is difficult to sort mutant (GFP-negative) embryos from stocks in which mutations are maintained over GFP balancer chromosomes. Since 2002, our group has been conducting deficiency and ectopic expression screens to identify ligands for orphan receptors. In order to do this, we developed streamlined protocols for live embryo dissection and antibody staining of collections containing hundreds of balanced lines. We have concluded that it is considerably more efficient to examine phenotypes in large collections of stocks by live dissection than by fixed dissection. Using the protocol described here, a single trained individual can screen up to 10 lines per day for phenotypes, examining 4-7 mutant embryos from each line under a compound microscope. This allows the identification of mutations conferring subtle, low-penetrance phenotypes, since up to 70 hemisegments per line are scored at high magnification with a 40X water-immersion lens.

Live Dissection of Drosophila Embryos: Streamlined Methods for Screening Mutant Collections by Antibody Staining

We describe a streamlined protocol for generating "fillet" preparations of Drosophila embryos of specific genotypes. This protocol allows efficient execution of a variety of genetic screens. It also allows excellent visualization of structures in the late embryo.

Drosophila embryos between stages 14 and 17 of embryonic development can be readily dissected to generate "fillet" preparations.  In these preparations, ...

MISSION esiRNA for RNAi Screening in Mammalian Cells

RNA interference (RNAi) is a basic cellular mechanism for the control of gene expression. RNAi is induced by short double-stranded RNAs also known as small interfering RNAs (siRNAs). The short double-stranded RNAs originate from longer double stranded precursors by the activity of Dicer, a protein of the RNase III family of endonucleases. The resulting fragments are components of the RNA-induced silencing complex (RISC), directing it to the cognate target mRNA. RISC cleaves the target mRNA thereby reducing the expression of the encoded protein1,2,3. RNAi has become a powerful and widely used experimental method for loss of gene function studies in mammalian cells utilizing small interfering RNAs.
Currently two main methods are available for the production of small interfering RNAs. One method involves chemical synthesis, whereas an alternative method employs endonucleolytic cleavage of target specific long double-stranded RNAs by RNase III in vitro. Thereby, a diverse pool of siRNA-like oligonucleotides is produced which is also known as endoribonuclease-prepared siRNA or esiRNA. A comparison of efficacy of chemically derived siRNAs and esiRNAs shows that both triggers are potent in target-gene silencing. Differences can, however, be seen when comparing specificity. Many single chemically synthesized siRNAs produce prominent off-target effects, whereas the complex mixture inherent in esiRNAs leads to a more specific knockdown10.
In this study, we present the design of genome-scale MISSION esiRNA libraries and its utilization for RNAi screening exemplified by a DNA-content screen for the identification of genes involved in cell cycle progression. We show how to optimize the transfection protocol and the assay for screening in high throughput. We also demonstrate how large data-sets can be evaluated statistically and present methods to validate primary hits. Finally, we give potential starting points for further functional characterizations of validated hits.

Here we use a human esiRNA library in a high-throughput screen for genes involved in cell division. We demonstrate how to set up and conduct an esiRNA screens, as well as how to analyze and validate the results.

RNA interference (RNAi) is a basic cellular mechanism for the control of gene expression. RNAi is induced by short double-stranded RNAs also known as ...

MISSION LentiPlex Pooled shRNA Library Screening in Mammalian Cells

RNA interference (RNAi) is an intrinsic cellular mechanism for the regulation of gene expression. Harnessing the innate power of this system enables us to knockdown gene expression levels in loss of gene function studies.
There are two main methods for performing RNAi. The first is the use of small interfering RNAs (siRNAs) that are chemically synthesized, and the second utilizes short-hairpin RNAs (shRNAs) encoded within plasmids 1. The latter can be transfected into cells directly or packaged into replication incompetent lentiviral particles. The main advantages of using lentiviral shRNAs is the ease of introduction into a wide variety of cell types, their ability to stably integrate into the genome for long term gene knockdown and selection, and their efficacy in conducting high-throughput loss of function screens. To facilitate this we have created the LentiPlex pooled shRNA library.
The MISSION LentiPlex Human shRNA Pooled Library is a genome-wide lentiviral pool produced using a proprietary process. The library consists of over 75,000 shRNA constructs from the TRC collection targeting 15,000+ human genes 2. Each library is tested for shRNA representation before product release to ensure robust library coverage. The library is provided in a ready-to-use lentiviral format at titers of at least 5 x 108 TU/ml via p24 assay and is pre-divided into ten subpools of approximately 8,000 shRNA constructs each. Amplification and sequencing primers are also provided for downstream target identification.
Previous studies established a synergistic antitumor activity of TRAIL when combined with Paclitaxel in A549 cells, a human lung carcinoma cell line 3, 4. In this study we demonstrate the application of a pooled LentiPlex shRNA library to rapidly conduct a positive selection screen for genes involved in the cytotoxicity of A549 cells when exposed to TRAIL and Paclitaxel. One barrier often encountered with high-throughput screens is the cost and difficulty in deconvolution; we also detail a cost-effective polyclonal approach utilizing traditional sequencing.

Here we use a human LentiPlex pooled library and traditional sequencing methods to identify gene targets promoting cell survival. We demonstrate how to set up and deconvolute a LentiPlex screen and validate the results.

RNA interference (RNAi) is an intrinsic cellular mechanism for the regulation of gene expression. Harnessing the innate power of this system enables us to ...

Conversion of a Capture ELISA to a Luminex xMAP Assay using a Multiplex Antibody Screening Method

The enzyme-linked immunosorbent assay (ELISA) has long been the primary tool for detection of analytes of interest in biological samples for both life science research and clinical diagnostics. However, ELISA has limitations. It is typically performed in a 96-well microplate, and the wells are coated with capture antibody, requiring a relatively large amount of sample to capture an antigen of interest . The large surface area of the wells and the hydrophobic binding of capture antibody can also lead to non-specific binding and increased background. Additionally, most ELISAs rely upon enzyme-mediated amplification of signal in order to achieve reasonable sensitivity. Such amplification is not always linear and can thus skew results.
In the past 15 years, a new technology has emerged that offers the benefits of the ELISA, but also enables higher throughput, increased flexibility, reduced sample volume, and lower cost, with a similar workflow 1, 2. Luminex xMAP Technology is a microsphere (bead) array platform enabling both monoplex and multiplex assays that can be applied to both protein and nucleic acid applications 3-5. The beads have the capture antibody covalently immobilized on a smaller surface area, requiring less capture antibody and smaller sample volumes, compared to ELISA, and non-specific binding is significantly reduced. Smaller sample volumes are important when working with limiting samples such as cerebrospinal fluid, synovial fluid, etc. 6. Multiplexing the assay further reduces sample volume requirements, enabling multiple results from a single sample.
Recent improvements by Luminex include: the new MAGPIX system, a smaller, less expensive, easier-to-use analyzer; Low-Concentration Magnetic MagPlex Microspheres which eliminate the need for expensive filter plates and come in a working concentration better suited for assay development and low-throughput applications; and the xMAP Antibody Coupling (AbC) Kit, which includes a protocol, reagents, and consumables necessary for coupling beads to the capture antibody of interest. (See Materials section for a detailed list of kit contents.)
In this experiment, we convert a pre-optimized ELISA assay for TNF-alpha cytokine to the xMAP platform and compare the performance of the two methods 7-11. TNF-alpha is a biomarker used in the measurement of inflammatory responses in patients with autoimmune disorders.
We begin by coupling four candidate capture antibodies to four different microsphere sets or regions. When mixed together, these four sets allow for the simultaneous testing of all four candidates with four separate detection antibodies to determine the best antibody pair, saving reagents, sample and time. Two xMAP assays are then constructed with the two most optimal antibody pairs and their performance is compared to that of the original ELISA assay in regards to signal strength, dynamic range, and sensitivity.

An ELISA can be easily converted to a Luminex xMAP assay and, through the benefits of multiplexing, several antibodies can be screened simultaneously to identify an optimum antibody pair, resulting in increased sensitivity and dynamic range, while reducing assay cost.

The enzyme-linked immunosorbent assay (ELISA) has long been the primary tool for detection of analytes of interest in biological samples for both life ...

High-throughput Functional Screening using a Homemade Dual-glow Luciferase Assay

We present a rapid and inexpensive high-throughput screening protocol to identify transcriptional regulators of alpha-synuclein, a gene associated with Parkinson&#39;s disease. 293T cells are transiently transfected with plasmids from an arrayed ORF expression library, together with luciferase reporter plasmids, in a one-gene-per-well microplate format. Firefly luciferase activity is assayed after 48 hr to determine the effects of each library gene upon alpha-synuclein transcription, normalized to expression from an internal control construct (a hCMV promoter directing Renilla luciferase). This protocol is facilitated by a bench-top robot enclosed in a biosafety cabinet, which performs aseptic liquid handling in 96-well format. Our automated transfection protocol is readily adaptable to high-throughput lentiviral library production or other functional screening protocols requiring triple-transfections of large numbers of unique library plasmids in conjunction with a common set of helper plasmids. We also present an inexpensive and validated alternative to commercially-available, dual luciferase reagents which employs PTC124, EDTA, and pyrophosphate to suppress firefly luciferase activity prior to measurement of Renilla luciferase. Using these methods, we screened 7,670 human genes and identified 68 regulators of alpha-synuclein. This protocol is easily modifiable to target other genes of interest.

We present a rapid and inexpensive screening method for identifying transcriptional regulators using high-throughput robotic transfections and a homemade dual-glow luciferase assay. This protocol rapidly generates direct side-by-side functional data for thousands of genes and is easily modifiable to target any gene of interest.

We present a rapid and inexpensive high-throughput screening protocol to identify transcriptional regulators of alpha-synuclein, a gene associated with ...

Induction and Analysis of Epithelial to Mesenchymal Transition

Epithelial to mesenchymal transition (EMT) is essential for proper morphogenesis during development. Misregulation of this process has been implicated as a key event in fibrosis and the progression of carcinomas to a metastatic state. Understanding the processes that underlie EMT is imperative for the early diagnosis and clinical control of these disease states. Reliable induction of EMT in vitro is a useful tool for drug discovery as well as to identify common gene expression signatures for diagnostic purposes. Here we demonstrate a straightforward method for the induction of EMT in a variety of cell types. Methods for the analysis of cells pre- and post-EMT induction by immunocytochemistry are also included. Additionally, we demonstrate the effectiveness of this method through antibody-based array analysis and migration/invasion assays.

A straightforward method is described for the induction of epithelial to mesenchymal transition (EMT) in a variety of cell types. Methods for the analysis of cells in EMT states by immunocytochemistry are included.

Epithelial  to mesenchymal transition (EMT) is essential for proper morphogenesis during  development. Misregulation of this  process has been implicated ...

Antibody Staining in C. Elegans Using &quot;Freeze-Cracking&quot;

To stain C. elegans with antibodies, the relatively impermeable cuticle must be bypassed by chemical or mechanical methods. "Freeze-cracking" is one method used to physically pull the cuticle from nematodes by compressing nematodes between two adherent slides, freezing them, and pulling the slides apart. Freeze-cracking provides a simple and rapid way to gain access to the tissues without chemical treatment and can be used with a variety of fixatives. However, it leads to the loss of many of the specimens and the required compression mechanically distorts the sample. Practice is required to maximize recovery of samples with good morphology. Freeze-cracking can be optimized for specific fixation conditions, recovery of samples, or low non-specific staining, but not for all parameters at once. For antibodies that require very hard fixation conditions and tolerate the chemical treatments needed to chemically permeabilize the cuticle, treatment of intact nematodes in solution may be preferred. If the antibody requires a lighter fix or if the optimum fixation conditions are unknown, freeze-cracking provides a very useful way to rapidly assay the antibody and can yield specific subcellular and cellular localization information for the antigen of interest.

Antibody Staining in C. Elegans Using &quot;Freeze-Cracking&quot;

"Freeze-cracking," a method for exposing the inner tissues of the nematode C. elegans to antibodies for protein localization, is demonstrated.

To stain C.  elegans with antibodies, the relatively impermeable cuticle must be  bypassed by chemical or mechanical methods.  "Freeze-cracking" is one ...

High-throughput Screening for Chemical Modulators of Post-transcriptionally Regulated Genes

Both transcriptional and post-transcriptional regulation have a profound impact on genes expression. However, commonly adopted cell-based screening assays focus on transcriptional regulation, being essentially aimed at the identification of promoter-targeting molecules. As a result, post-transcriptional mechanisms are largely uncovered by gene expression targeted drug development. Here we describe a cell-based assay aimed at investigating the role of the 3&#39; untranslated region (3&#8217; UTR) in the modulation of the fate of its mRNA, and at identifying compounds able to modify it. The assay is based on the use of a luciferase reporter construct containing the 3&#8217; UTR of a gene of interest stably integrated into a disease-relevant cell line. The protocol is divided into two parts, with the initial focus on the primary screening aimed at the identification of molecules affecting luciferase activity after 24 hr of treatment. The second part of the protocol describes the counter-screening necessary to discriminate compounds modulating luciferase activity specifically through the 3&#8217; UTR. In addition to the detailed protocol and representative results, we provide important considerations about the assay development and the validation of the hit(s) on the endogenous target. The described cell-based reporter gene assay will allow scientists to identify molecules modulating protein levels via post-transcriptional mechanisms dependent on a 3&#8217; UTR.

Here we describe a cell-based reporter gene assay as a valuable tool to screen chemical libraries for compounds modulating post-transcriptional control mechanisms exerted through 3&#8217; UTR.

Both transcriptional and post-transcriptional regulation have a profound impact on genes expression. However, commonly adopted cell-based screening assays ...

Identification of Kinase-substrate Pairs Using High Throughput Screening

We have developed a screening platform to identify dedicated human protein kinases for phosphorylated substrates which can be used to elucidate novel signal transduction pathways. Our approach features the use of a library of purified GST-tagged human protein kinases and a recombinant protein substrate of interest. We have used this technology to identify MAP/microtubule affinity-regulating kinase 2 (MARK2) as the kinase for a glucose-regulated site on CREB-Regulated Transcriptional Coactivator 2 (CRTC2), a protein required for beta cell proliferation, as well as the Axl family of tyrosine kinases as regulators of cell metastasis by phosphorylation of the adaptor protein ELMO. We describe this technology and discuss how it can help to establish a comprehensive map of how cells respond to environmental stimuli.

Protein phosphorylation is a central feature of how cells interpret and respond to information in their extracellular milieu. Here, we present a high throughput screening protocol using kinases purified from mammalian cells to rapidly identify kinases that phosphorylate a substrate(s) of interest.


We have developed a screening platform to identify dedicated human protein kinases for phosphorylated substrates which can be used to elucidate novel ...

Multi-enzyme Screening Using a High-throughput Genetic Enzyme Screening System

The recent development of a high-throughput single-cell assay technique enables the screening of novel enzymes based on functional activities from a large-scale metagenomic library1. We previously proposed a genetic enzyme screening system (GESS) that uses dimethylphenol regulator activated by phenol or p-nitrophenol. Since a vast amount of natural enzymatic reactions produce these phenolic compounds from phenol deriving substrates, this single genetic screening system can be theoretically applied to screen over 200 different enzymes in the BRENDA database. Despite the general applicability of GESS, applying the screening process requires a specific procedure to reach the maximum flow cytometry signals. Here, we detail the developed screening process, which includes metagenome preprocessing with GESS and the operation of a flow cytometry sorter. Three different phenolic substrates (p-nitrophenyl acetate, p-nitrophenyl-&#946;-D-cellobioside, and phenyl phosphate) with GESS were used to screen and to identify three different enzymes (lipase, cellulase, and alkaline phosphatase), respectively. The selected metagenomic enzyme activities were confirmed only with the flow cytometry but DNA sequencing and diverse in vitro analysis can be used for further gene identification.

This work presents a method of high-throughput screening using a universal genetic enzyme screening system that can be theoretically applied to over 200 enzymes. Here, the single screening system identifies three different enzymes (lipase, cellulase, and alkaline phosphatase) by simply changing the substrate used (p-nitrophenyl acetate, p-nitrophenyl-&#946;-D-cellobioside, and phenyl phosphate).

The recent development of a high-throughput single-cell assay technique enables the screening of novel enzymes based on functional activities from a ...