Name: a protein microarray assay for serological determination of antigen-specific antibody responses following clostridium difficile infection
Uploaded: 2018-06-15T14:00:00
Description: Watch this Scientific Journal Video about A Protein Microarray Assay for Serological Determination of Antigen-specific Antibody Responses Following Clostridium difficile Infection at JoVE.com

This research was supported by a Hermes Fellowship to Ola Negm and Tanya Monaghan and through separate funding from the Nottingham Digestive Diseases Centre and the NIHR Nottingham Digestive Diseases Biomedical Research Centre.

1. Preparing a Microarray Plate
<ol>
	<li>Dilute C. difficile antigens with a printing buffer [PBS-Tween-trehalose (50 mM)] at the optimum concentration (which was predefined before running the patient sera): toxin A (200 &#181;g/mL) and toxin B (100 &#181;g/mL), pCDTb (200 &#181;g/mL), and purified native whole SLPs derived from ribotypes 001, 002, and 027 (200 &#181;g/mL). 
	NOTE: Toxin B was obtained from a toxin B-expressing strain CCUG 20309 (90 &#181;g/mL).
	<ol>
		<li>Dilute the positive controls, ...

<ol>
	<li>Negm, O. 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=Profiling+humoral+immune+responses+to+Clostridium+difficile.-specific+antigens+by+protein+microarray+analysis.">Profiling humoral immune responses to Clostridium difficile.-specific antigens by protein microarray analysis.</a> Clinical and Vaccine Immunology. 22 (9), 1033-1039 (2015).</li><li>Monaghan, T. 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=High+prevalence+of+subclass-specific+binding+and+neutralizing+antibodies+against+Clostridium+difficile.+toxins+in+adult+cystic+fibrosis+sera:+possible+mode+of+immunoprotection+against+symptomatic+C.+difficile+infection.">High prevalence of subclass-specific binding and neutralizing antibodies against Clostridium difficile. toxins in adult cystic fibrosis sera: possible mode of immunoprotection against symptomatic C. difficile infection.</a> Clinical and Experimental Gastroenterology. 10, 169-175 (2017).</li><li>Negm, O. 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=Protective+antibodies+against+Clostridium+difficile.+are+present+in+intravenous+immunoglobulin+and+are+retained+in+humans+following+its+administration.">Protective antibodies against Clostridium difficile. are present in intravenous immunoglobulin and are retained in humans following its administration.</a> Clinical &amp; Experimental Immunology. 188 (3), 437-443 (2017).</li><li>Monaghan, T., 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=OC-058+A+protein+microarray+assay+for+predicting+severe+outcomes+in+Clostridium+difficile+infection.">OC-058 A protein microarray assay for predicting severe outcomes in Clostridium difficile infection.</a> Gut. 66, 31 (2017).</li><li>Bacon, A. E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Immunoglobulin+G+directed+against+toxins+A+and+B+of+Clostridium+difficile+in+the+general+population+and+patients+with+antibiotic-associated+diarrhea.">Immunoglobulin G directed against toxins A and B of Clostridium difficile in the general population and patients with antibiotic-associated diarrhea.</a> Diagnostic Microbiology and Infectious Disease. 18 (4), 205-209 (1994).</li><li>Viscidi, 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=Serum+antibody+response+to+toxins+A+and+B+of+Clostridium+difficile.">Serum antibody response to toxins A and B of Clostridium difficile.</a> The Journal of Infectious Diseases. 148 (1), 93-100 (1983).</li><li>Salcedo, 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=Intravenous+immunoglobulin+therapy+for+severe+Clostridium+difficile+colitis.">Intravenous immunoglobulin therapy for severe Clostridium difficile colitis.</a> Gut. 41 (3), 366-370 (1997).</li><li>Abougergi, M. S., Kwon, J. H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Intravenous+immunoglobulin+for+the+treatment+of+Clostridium+difficile+infection:+a+review.">Intravenous immunoglobulin for the treatment of Clostridium difficile infection: a review.</a> Digestive Diseases and Sciences. 56 (1), 19-26 (2011).</li><li>Shah, N., Shaaban, H., Spira, R., Slim, J., Boghossian, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Intravenous+immunoglobulin+in+the+treatment+of+severe+Clostridium+difficile+colitis.">Intravenous immunoglobulin in the treatment of severe Clostridium difficile colitis.</a> Journal of Global Infectious Diseases. 6 (2), 82-85 (2014).</li><li>Kyne, L., Warny, M., Qamar, A., Kelly, C. P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Asymptomatic+carriage+of+Clostridium+difficile+and+serum+levels+of+IgG+antibody+against+toxin+A.">Asymptomatic carriage of Clostridium difficile and serum levels of IgG antibody against toxin A.</a> The New England Journal of Medicine. 342 (6), 390-397 (2000).</li><li>Solomon, K., 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=Mortality+in+patients+with+Clostridium+difficile+infection+correlates+with+host+pro-inflammatory+and+humoral+immune+responses.">Mortality in patients with Clostridium difficile infection correlates with host pro-inflammatory and humoral immune responses.</a> Journal of Medical Microbiology. 62, 1453-1460 (2013).</li><li>Kyne, L., Warny, M., Qamar, A., Kelly, C. P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Association+between+antibody+response+to+toxin+A+and+protection+against+recurrent+Clostridium+difficile+diarrhoea.">Association between antibody response to toxin A and protection against recurrent Clostridium difficile diarrhoea.</a> Lancet. 357 (9251), 189-193 (2001).</li><li>Leav, B. 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=Serum+anti-toxin+B+antibody+correlates+with+protection+from+recurrent+Clostridium+difficile+infection+(CDI).">Serum anti-toxin B antibody correlates with protection from recurrent Clostridium difficile infection (CDI).</a> Vaccine. 28 (4), 965-969 (2010).</li><li>Drudy, D., 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+antibody+response+to+surface+layer+proteins+in+Clostridium+difficile+infection.">Human antibody response to surface layer proteins in Clostridium difficile infection.</a> FEMS Immunology and Medical Microbiology. 41 (3), 237-242 (2004).</li><li>Bauer, M. P., Nibbering, P. H., Poxton, I. R., Kuijper, E. J., van Dissel, J. T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Humoral+immune+response+as+predictor+of+recurrence+in+Clostridium+difficile+infection.">Humoral immune response as predictor of recurrence in Clostridium difficile infection.</a> Clinical Microbiology and Infection. 20 (12), 1323-1328 (2014).</li><li>Wilcox, M. 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=Bezlotoxumab+for+prevention+of+recurrent+Clostridium+difficile+infection.">Bezlotoxumab for prevention of recurrent Clostridium difficile infection.</a> The New England Journal of Medicine. 376 (4), 305-317 (2017).</li><li>Leuzzi, R., Adamo, R., Scarselli, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Vaccines+against+Clostridium+difficile.">Vaccines against Clostridium difficile.</a> Human Vaccines &amp; Immunotherapeutics. 10 (6), 1466-1477 (2014).</li><li>Ghose, C., Kelly, C. P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+prospect+for+vaccines+to+prevent+Clostridium+difficile+infection.">The prospect for vaccines to prevent Clostridium difficile infection.</a> Infectious Disease Clinics of North America. 29 (1), 145-162 (2015).</li><li>Henderson, M., Bragg, A., Fahim, G., Shah, M., Hermes-DeSantis, E. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+review+of+the+safety+and+efficacy+of+vaccines+as+prophylaxis+for+Clostridium+difficile+infections.">A review of the safety and efficacy of vaccines as prophylaxis for Clostridium difficile infections.</a> Vaccines. 5 (3), (2017).</li><li>Zhu, 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=Global+analysis+of+protein+activities+using+proteome+chips.">Global analysis of protein activities using proteome chips.</a> Science. 293 (5537), 2101-2105 (2001).</li><li>Delehanty, J. B., Ligler, F. S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Method+for+printing+functional+protein+microarrays.">Method for printing functional protein microarrays.</a> BioTechniques. 34 (2), 380-385 (2003).</li><li>Sutandy, F. X., Qian, J., Chen, C. S., Zhu, H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Overview+of+protein+microarrays.">Overview of protein microarrays.</a> Current Protocols in Protein Science. , 21 (2013).</li><li>Huang, Y., Zhu, H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Protein+array-based+approaches+for+biomarker+discovery+in+cancer.">Protein array-based approaches for biomarker discovery in cancer.</a> Genomics, Proteomics &amp; Bioinformatics. 15 (2), 73-81 (2017).</li><li>Vigil, A., Davies, D. H., Felgner, P. L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Defining+the+humoral+immune+response+to+infectious+agents+using+high-density+protein+microarrays.">Defining the humoral immune response to infectious agents using high-density protein microarrays.</a> Future Microbiology. 5 (2), 241-251 (2010).</li><li>Bacarese-Hamilton, T., Mezzasoma, L., Ardizzoni, A., Bistoni, F., Crisanti, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Serodiagnosis+of+infectious+diseases+with+antigen+microarrays.">Serodiagnosis of infectious diseases with antigen microarrays.</a> Journal of Applied Microbiology. 96 (1), 10-17 (2004).</li><li>Davies, D. 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=Profiling+the+humoral+immune+response+to+infection+by+using+proteome+microarrays:+high-throughput+vaccine+and+diagnostic+antigen+discovery.">Profiling the humoral immune response to infection by using proteome microarrays: high-throughput vaccine and diagnostic antigen discovery.</a> Proceedings of the National Academy of Sciences of the United States of America. 102 (3), 547-552 (2005).</li><li>Wadia, P. P., Sahaf, B., Miklos, D. B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Recombinant+antigen+microarrays+for+serum/plasma+antibody+detection.">Recombinant antigen microarrays for serum/plasma antibody detection.</a> Methods in Molecular Biology. 723, 81-104 (2011).</li><li>Moore, C. D., Ajala, O. Z., Zhu, H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Applications+in+high-content+functional+protein+microarrays.">Applications in high-content functional protein microarrays.</a> Current Opinion in Chemical Biology. 30, 21-27 (2016).</li><li>Crompton, P. D., 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+prospective+analysis+of+the+Ab+response+to+Plasmodium+falciparum+before+and+after+a+malaria+season+by+protein+microarray.">A prospective analysis of the Ab response to Plasmodium falciparum before and after a malaria season by protein microarray.</a> Proceedings of the National Academy of Sciences of the United States of America. 107 (15), 6958-6963 (2010).</li><li>Khodakov, D. 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=An+oligonucleotide+microarray+for+multiplex+real-time+PCR+identification+of+HIV-1,+HBV,+and+HCV.">An oligonucleotide microarray for multiplex real-time PCR identification of HIV-1, HBV, and HCV.</a> BioTechniques. 44 (2), 241-246 (2008).</li><li>Ryabinin, V. 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=Universal+oligonucleotide+microarray+for+sub-typing+of+Influenza+A+virus.">Universal oligonucleotide microarray for sub-typing of Influenza A virus.</a> PLoS One. 6 (4), 17529 (2011).</li><li>Zhu, 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=Severe+acute+respiratory+syndrome+diagnostics+using+a+coronavirus+protein+microarray.">Severe acute respiratory syndrome diagnostics using a coronavirus protein microarray.</a> Proceedings of the National Academy of Sciences of the United States of America. 103 (11), 4011-4016 (2006).</li><li>Cleton, N. B., 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=Spot+the+difference:+development+of+a+syndrome+based+protein+microarray+for+specific+serological+detection+of+multiple+flavivirus+infections+in+travelers.">Spot the difference: development of a syndrome based protein microarray for specific serological detection of multiple flavivirus infections in travelers.</a> PloS Neglected Tropical Diseases. 9 (3), 0003580 (2015).</li><li>Liu, Y., Yu, F., Huang, H., Han, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Development+of+recombinant+antigen+array+for+simultaneous+detection+of+viral+antibodies.">Development of recombinant antigen array for simultaneous detection of viral antibodies.</a> PLoS One. 8 (9), 73842 (2013).</li><li>Zhou, F., 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=Protein+array+identification+of+protein+markers+for+serodiagnosis+of+Mycobacterium+tuberculosis+infection.">Protein array identification of protein markers for serodiagnosis of Mycobacterium tuberculosis infection.</a> Scientific Reports. 5, 15349 (2015).</li><li>Mannsperger, H. A., Gade, S., Henjes, F., Beissbarth, T., Korf, U. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=RPPanalyzer:+analysis+of+reverse-phase+protein+array+data.">RPPanalyzer: analysis of reverse-phase protein array data.</a> Bioinformatics. 26 (17), 2202-2203 (2010).</li><li>Monaghan, T. 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=Circulating+antibody+and+memory+B-cell+responses+to+C.+difficile-associated+diarrhoea,+inflammatory+bowel+disease+and+cystic+fibrosis.">Circulating antibody and memory B-cell responses to C. difficile-associated diarrhoea, inflammatory bowel disease and cystic fibrosis.</a> PLoS One. 8 (9), 74452 (2013).</li><li>Grainger, D. W., Greef, C. H., Gong, P., Lochhead, 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=Current+microarray+surface+chemistries.">Current microarray surface chemistries.</a> Methods in Molecular Biology. 381, 37-75 (2007).</li><li>Wellhausen, R., Seitz, H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Facing+current+quantification+challenges+in+protein+microarrays.">Facing current quantification challenges in protein microarrays.</a> Journal of Biomedicine and Biotechnology. 2012, (2012).</li><li>Guo, A., Zhu, X. -. Y. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+critical+role+of+surface+chemistry+in+protein+microarrays.">The critical role of surface chemistry in protein microarrays.</a> Functional Protein Microarrays in Drug Discovery. , (2007).</li></ol>

In this protocol, we have shown that microarray is a suitable platform for defining humoral immune responses to C. difficile protein antigens in patient sera (Figures 3 and 6) and commercial preparations of IVIg (Figure 5). We have also demonstrated that the microarray technique performs well when compared to conventional ELISA (Figure 2) and shows excellent reproducibility, with intra- and inter-assay variabilities fal...

This protocol describes the development and validation of a novel and customized protein microarray assay for the detection and semi-quantification of bacterial strain and isotype-specific antibody responses to C. difficile antigens. We successfully use our C. difficile-specific microarray assay as a promising new tool for the compositional bioanalysis of specific antibody content in patient sera1,2, preparations of IVIg3, and identification of antibody specificities that correlate with poor outcomes in CDI4. We demonstrate how biobanked serum samples and commercial preparations of IVIg can be analyzed on microarray slides, allowing high-quality reproducible profiling of C. difficile pathogen-specific antibody responses in this assay.
Many healthy children and adults have detectable serum IgG and IgA antibodies to C. difficile toxins A and B5,6. These are thought to arise following transient exposure during infancy and following exposure to C. difficile in adulthood. For this reason, polyclonal IVIg has been used off-label to treat both recurrent and fulminant CDI7,8,9. However, its definitive role and mode of action remains unclear. Several studies have shown that the humoral immune response to C. difficile toxins plays a role in disease presentation and outcome. Specifically, asymptomatic patients show an increased serum anti-toxin A IgG concentration compared to patients who develop symptomatic disease10. A demonstrable association has been reported for median anti-toxin A IgG titers and 30-day all-cause mortality11. Several reports have also revealed an association with a protection against recurrence and antibody responses to toxin A, B, and several non-toxin antigens (Cwp66, Cwp84, FliC, FliD, and surface layer proteins (SLPs))12,13,14,15. These observations have spurred the development of the first passive immunotherapy drug targeting C. difficile toxin B (bezlotuxumab), which has recently been approved by the US Food and Drug Administration and the European Medicines Agency for the prevention of recurrent CDI16. Vaccination strategies using inactivated toxins or recombinant toxin fragments are also currently under development17,18,19. These new therapeutic approaches will undoubtedly stimulate the requirement for evaluating humoral immune responses to multiple antigens in large sample sizes.
Today, there is a notable lack of commercially available high-throughput assays capable of simultaneously assessing bacterial strain and isotype-specific antibody responses to C. difficile antigens. There is an unmet need to develop such assays to facilitate future research efforts and clinical applications. Protein microarrays are a method to immobilize large numbers of individually-purified proteins as a spatially organized array of spots onto a microscopic slide-based surface by using a robotic system, which can be either a contact20 or a non-contact printing tool21. The spots may represent complex mixtures such as cell lysates, antibodies, tissue homogenates, endogenous or recombinant proteins or peptides, body fluids or drugs22,23.
Protein microarray technology offers distinct advantages over standard in-house ELISA techniques, which have traditionally been used to assess anti-C. difficile antibody responses. These include an increased capacity for detecting a range of multi-isotype-specific antibodies against a more extensive panel of protein targets, reduced volume requirements for antigens, samples, and reagents, and an enhanced ability to incorporate a larger number of technical replicates, in addition to multiple internal quality control (QC) measures1. Microarrays are therefore more sensitive, accurate, and reproducible and have a greater dynamic range. These factors make microarrays a cheaper and potentially favorable alternative to ELISAs for the large-scale detection of known proteins. However, disadvantages of microarray technology result mainly from the large up-front costs associated with establishing a panel of highly purified antigens and setting up the technological platform.
Protein microarrays have been extensively used over the past two decades as a diagnostic and basic research tool in clinical applications. Specific applications include protein expression profiling, the study of enzyme-substrate relationships, biomarker screening, analysis of host-microbe interactions, and profiling antibody specificity23,24,25,26,27,28. Many new pathogen protein/antigen microarrays have been established, including malaria (Plasmodium)29, HIV-130, influenza31, severe acute respiratory syndrome (SARS)32, viral hemorrhagic fever33, herpesviruses34, and tuberculosis35.
The present protocol relates to the establishment of an easy operating C. difficile reactive antigen microarray assay, which enables accurate, precise, and specific quantification of multi-isotype and strain-specific antibody responses to C. difficile antigens in sera and polyclonal IVIg. Herein, we include representative results pertaining to an acceptable microarray assay performance when compared to ELISA as well as assay precision and reproducibility profiles. This assay could be further developed to profile other clinical samples and sets a new standard for research into the molecular basis of CDI.

<table border="0" cellpadding="0" cellspacing="0" style="width:1827px;" width="1826">
	<colgroup>
		<col />
		<col />
		<col />
		<col />
	</colgroup>
	<tbody>
		<tr height="21">
			<td height="21" style="height:21px;width:399px;">BioRobotics MicroGrid II arrayer</td>
			<td style="width:296px;">Digilab, Malborough, MA, USA</td>
			<td style="width:296px;">N/A</td>
			<td style="width:836px;">Contact arrayer used to automated spotting of the antigens onto the slides.</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Scanner InnoScan 710.</td>
			<td>Innopsys</td>
			<td>N/A</td>
			<td>A fluorescent microarray slide scanner with a red (Cy5) laser to read the reaction.</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">MAPIX software version 7.2.0</td>
			<td>Innopsys</td>
			<td>N/A</td>
			<td>Measure signal intensities of the spots.</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Silicon contact pin</td>
			<td>Parallel Synthesis Technologies</td>
			<td>SMT-P75</td>
			<td>Print the samples onto the slides.</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Thermo Scientific Nalgene Desiccator</td>
			<td>Thermo Scientific</td>
			<td>41102426</td>
			<td>To store the new and printed slides.</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">384-well plate</td>
			<td>Genetix</td>
			<td>X7022UN</td>
			<td>To prepare the antigens.</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Plate cover</td>
			<td>Sigma Aldrich, UK</td>
			<td>CLS6570-100EA</td>
			<td>To reduce evaporation of the samples.</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Aminosilane slides</td>
			<td>Schott,&#160; Germany</td>
			<td>1064875</td>
			<td>The slide of choice for printing the antigens.</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Slide holders</td>
			<td>GraceBio Labs, USA</td>
			<td>204862</td>
			<td>Divide the slides into identical 16 subarrays. These holders are re-usable, removable, leak-proof wells .&#160;</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Candida albicans lysate</td>
			<td>NIBSC</td>
			<td>PR-BA117-S</td>
			<td>Positive control</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Tetanus Toxoid&#160;</td>
			<td>Athens Research and Technology</td>
			<td>04/150</td>
			<td>Positive control</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Immunoglobulin G (IgG), Normal Human Plasma</td>
			<td>&#160;Athens research and&#160; technology&#160;&#160;</td>
			<td>16-16-090707</td>
			<td>Purified Native Human Immunoglobulin G IgG, Human Plasma.&#160;</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Immunoglobulin G1 (IgG1), Normal Human Plasma</td>
			<td>&#160;Athens research and&#160; technology&#160;&#160;</td>
			<td>16-16-090707-1</td>
			<td>Purified Native Human Immunoglobulin G1 IgG1, Human Plasma.&#160;</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Immunoglobulin G2 (IgG2), Normal Human Plasma</td>
			<td>&#160;Athens research and&#160; technology&#160;&#160;</td>
			<td>16-16-090707-2</td>
			<td>Purified Native Human Immunoglobulin G2 IgG2, Human Plasma.&#160;</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Immunoglobulin G3 (IgG3), Normal Human Plasma</td>
			<td>&#160;Athens research and&#160; technology&#160;&#160;</td>
			<td>16-16-090707-3</td>
			<td>Purified Native Human Immunoglobulin G3 IgG3, Human Plasma.&#160;</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Immunoglobulin G4 (IgG4), Normal Human Plasma</td>
			<td>&#160;Athens research and&#160; technology&#160;&#160;</td>
			<td>16-16-090707-4</td>
			<td>Purified Native Human Immunoglobulin G4 IgG4, Human Plasma.&#160;</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Immunoglobulin A (IgA), Human Plasma</td>
			<td>&#160;Athens research and&#160; technology&#160;&#160;</td>
			<td>16-16-090701</td>
			<td>Purified Native Human Immunoglobulin A (IgA), Human Plasma.</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Immunoglobulin A1 (IgA1), Human Myeloma Plasma</td>
			<td>&#160;Athens research and&#160; technology&#160;&#160;</td>
			<td>16-16-090701-1M</td>
			<td>Purified Native Human Immunoglobulin A1 (IgA1), Human Plasma.</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Immunoglobulin A2 (IgA2), Human Myeloma Plasma</td>
			<td>&#160;Athens research and&#160; technology&#160;&#160;</td>
			<td>16-16-090701-2M</td>
			<td>Purified Native Human Immunoglobulin A2 (IgA2), Human Plasma.</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Immunoglobulin M (IgM), Human Plasma</td>
			<td>&#160;Athens research and&#160; technology&#160;&#160;</td>
			<td>16-16-090713</td>
			<td>Purified Native Human Immunoglobulin M (IgM), Human Plasma.</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Biotinylated Goat Anti-Human IgG Antibody, gamma chain specific</td>
			<td>Vector Labs</td>
			<td>BA-3080</td>
			<td>Goat anti- human IgG (&#947;-chain specific)-biotin antibody reacts specifically with human IgG but not with other immunoglobulins.</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Mouse Anti-Human IgG1 Hinge-BIOT</td>
			<td>Southern Biotec</td>
			<td>9052-08&#160;</td>
			<td>Goat anti- human IgG1 biotin antibody reacts specifically with human IgG1 but not with other immunoglobulins.</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Mouse Anti-Human IgG2 Fc-BIOT</td>
			<td>Southern Biotec</td>
			<td>9060-08&#160;&#160;</td>
			<td>Goat anti- human IgG2 -biotin antibody reacts specifically with human IgG 2but not with other immunoglobulins.</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Mouse Anti-Human IgG3 Hinge-BIOT</td>
			<td>Southern Biotec</td>
			<td>9210-08&#160;&#160;&#160;</td>
			<td>Goat anti- human IgG3-biotin antibody reacts specifically with human IgG3 but not with other immunoglobulins.</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Mouse Anti-Human IgG4 pFc&#39;-BIOT</td>
			<td>Southern Biotec</td>
			<td>9190-08&#160;&#160;</td>
			<td>Goat anti- human IgG-biotin antibody reacts specifically with human IgG but not with other immunoglobulins.</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Anti-Human IgA, alpha chain specific, made in goat - Biotinylated</td>
			<td>Vector Labs</td>
			<td>BA-3030</td>
			<td>Goat anti- human IgG -biotin antibody reacts specifically with human IgG but not with other immunoglobulins.</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Mouse Anti-Human IgA1-BIOT</td>
			<td>Southern Biotec</td>
			<td>9130-08</td>
			<td>Goat anti- human IgG -biotin antibody reacts specifically with human IgG but not with other immunoglobulins.</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Mouse Anti-Human IgA2-BIOT</td>
			<td>Southern Biotec</td>
			<td>9140-08&#160;&#160;</td>
			<td>Goat anti- human IgG -biotin antibody reacts specifically with human IgG but not with other immunoglobulins.</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Mouse Anti-Human IgM-BIOT</td>
			<td>Southern Biotec</td>
			<td>9020-08&#160;</td>
			<td>Goat anti- human IgG-biotin antibody reacts specifically with human IgG but not with other immunoglobulins.</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">0.2 mm syringe filter</td>
			<td>Thermo scientific</td>
			<td>723-2520</td>
			<td>Filter the 5% BSA.</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Bovine Serum Albumin (BSA)</td>
			<td>Sigma Aldrich, UK</td>
			<td>A7284</td>
			<td>Use 5% BSA for blocking the slides.</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Antibody diluent</td>
			<td>Dako, UK</td>
			<td>S3022</td>
			<td>To dilute the serum and the secondary antibody.</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Streptavidin Cy5</td>
			<td>eBioscience</td>
			<td>SA1011</td>
			<td>Detection of the immune reaction.</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Purified whole C. difficile toxins A and B (toxinotype 0, strain VPI 10463, ribotype 087)</td>
			<td>Toxins Group, Public Health England</td>
			<td>NA</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Purified whole C. difficile toxin B (CCUG 20309 toxin B only expressing strain)</td>
			<td>Toxins Group, Public Health England</td>
			<td>NA</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Precursor form of B fragment of binary toxin, pCDTb</td>
			<td>University of Bath&#160;</td>
			<td>NA</td>
			<td>Produced in E. Coli from wholly synthetic recombinant gene construct. Amino acid sequence based on published sequence from 027 ribotype (http:www.uniprot.org/uniprot/A8DS70)</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Purified native whole ribotype-specific (001, 002, 027) surface layer proteins</td>
			<td>Dublin City University&#160;</td>
			<td>NA</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Vigam (IVIg preparation 1)</td>
			<td>Nottingham University Hospitals NHS Trust</td>
			<td>N/A</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Privigen (IVIg preparation 2)</td>
			<td>Nottingham University Hospitals NHS Trust</td>
			<td>N/A</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Intratect (IVIg preparation 3)</td>
			<td>Nottingham University Hospitals NHS Trust</td>
			<td>N/A</td>
			<td></td>
		</tr>
	</tbody>
</table>

a protein microarray assay for serological determination of antigen-specific antibody responses following clostridium difficile infection

We provide a detailed overview of a novel high-throughput protein microarray assay for the determination of anti-Clostridium difficile antibody levels in human sera and in separate preparations of polyclonal intravenous immunoglobulin (IVIg). The protocol describes the methodological steps involved in sample preparation, printing of arrays, assay procedure, and data analysis. In addition, this protocol could be further developed to incorporate diverse clinical samples including plasma and cell culture supernatants. We show how protein microarray can be used to determine a combination of isotype (IgG, IgA, IgM), subclass (IgG1, IgG2, IgG3, IgG4, IgA1, IgA2), and strain-specific antibodies to highly purified whole C. difficile toxins A and B (toxinotype 0, strain VPI 10463, ribotype 087), toxin B from a C. difficile toxin-B-only expressing strain (CCUG 20309), a precursor form of a B fragment of binary toxin, pCDTb, ribotype-specific whole surface layer proteins (SLPs; 001, 002, 027), and control proteins (tetanus toxoid and Candida albicans). During the experiment, microarrays are probed with sera from individuals with C. difficile infection (CDI), individuals with cystic fibrosis (CF) without diarrhea, healthy controls (HC), and from individuals pre- and post-IVIg therapy for the treatment of CDI, combined immunodeficiency disorder, and chronic inflammatory demyelinating polyradiculopathy. We encounter significant differences in toxin neutralization efficacies and multi-isotype specific antibody levels between patient groups, commercial preparations of IVIg, and sera before and following IVIg administration. Also, there is a significant correlation between microarray and enzyme-linked immunosorbent assay (ELISA) for antitoxin IgG levels in serum samples. These results suggest that microarray could become a promising tool for profiling antibody responses to C.difficile antigens in vaccinated or infected humans. With further refinement of antigen panels and a reduction in production costs, we anticipate that microarray technology may help optimize and select the most clinically useful immunotherapies for C. difficile infection in a patient-specific manner.

Figure 1 illustrates a flowchart describing the major steps in the described protocol. Figure 2 shows Spearman correlation tests demonstrating significant agreement between microarray and ELISA for IgG and IgA anti-toxin A and B levels in the patient test sera. Figure 3 shows differential IgG and IgA antibody-class specific antibody responses to toxin A, toxin B, and binary toxin (pCDTb) in patients ...

Watch this Scientific Journal Video about A Protein Microarray Assay for Serological Determination of Antigen-specific Antibody Responses Following Clostridium difficile Infection at JoVE.com

A Protein Microarray Assay for Serological Determination of Antigen-specific Antibody Responses Following Clostridium difficile Infection

This article describes a simple protein microarray method for profiling humoral immune responses to a 7-plex panel of highly purified Clostridium difficile antigens in human sera. The protocol can be extended for the determination of specific antibody responses in preparations of polyclonal intravenous immunoglobulin.

A Protein Microarray Assay for Serological Determination of Antigen-specific Antibody Responses Following Clostridium difficile Infection

We provide a detailed overview of a novel high-throughput protein microarray assay for the determination of anti-Clostridium difficile antibody levels in ...

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