Flow cytometric analysis of within-strain variation in polysaccharide expression by Bacteroides fragilis by use of murine monoclonal antibodies.

The reactivity of four different monoclonal antibodies (MAbs) with populations of Bacteroides fragilis NCTC 9343, enriched by density gradient centrifugation for a large capsule, small capsule and electron-dense layer (EDL) only visible by electronmicroscopy, was examined. The MAbs reacted strongly with polysaccharides present in both the large capsule- and EDL-enriched populations but not in the small capsule-enriched populations. The pattern of labelling was determined by immunoblotting, immunofluorescence and immuno-electronmicroscopy, and flow cytometry. The MAbs labelled cell membrane-associated epitopes in the large capsule- and EDL-enriched populations and cell-free material in the EDL population. By immunoblotting, ladders of repeating polysaccharide subunits were evident in the EDL population but not in the large capsule population. The proportion of cells labelled within each population was determined by flow cytometry. The reactivity of another MAb with the small capsule population was confirmed by flow cytometry. A qualitative indication of epitope expression was obtained by examination of the flow cytometric profiles. Differential expression of the same saccharide epitope was observed both between and within structurally distinct B. fragilis populations. The MAbs were species-specific and cross-reacted with several recent clinical isolates. These polysaccharides may be relevant to the virulence of B. fragilis.

Production, characterisation and applications of monoclonal antibodies to two novel porcine bocaviruses from swine in Northern Ireland

The production, preliminary characterisation and applications of monoclonal antibodies (mAbs) against two novel swine bocaviruses isolated in cell culture from swine in Northern Ireland are described. Of the 17 stable final clones produced, four were characterised. All were of the IgG2a isotype and showed no cross-reactivity with either bocavirus strain. Partial neutralisation was observed with PBoV4 mAbs and homologous virus. The two mAbs selected for use in antigen-detecting ELISAs were successful in highlighting those fractions containing infectious virus within sucrose gradients. This is the first report of the production of specific reagents that will prove useful in the study of the biology of these viruses and swine bocavirus-associated diseases.

Development of a Broad-Specificity Monoclonal Antibody-Based Immunoaffinity Chromatography Cleanup for Organophosphorus Pesticide Determination in Environmental Samples

An immunoaffinity chromatographic (IAC) method for the selective extraction and concentration of 13 organophosphorus pesticides (OPs, including coumaphos, parathion, phoxim, quinalphos, dichlofenthion, triazophos, azinphos-ethyl, phosalone, isochlorthion, parathion-methyl, cyanophos, disulfoton, and phorate) prior to analysis by high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) was developed. The IAC column was prepared by covalently immobilizing a monoclonal antibody with broad specificity for OPs on CNBr-activated Sephrose 4B. The column capacity ranged from 884 to 2641 ng/mL of gel. The optimum elution solvent was 0.01 M phosphate-buffered saline containing 80% methanol. The breakthrough volume of the IAC column was found to be 400 mL. Recoveries of OPs from spiked environmental samples by IAC cleanup and HPLC-MS/MS analysis ranged from 60.2 to 107.1%, with a relative standard deviation below 11.1%. The limit of quantitation for 13 OPs ranged from 0.01 to 0.13 ng/mL (ng/g). The application of IAC cleanup coupled to HPLC-MS/MS in real environmental samples demonstrated the potential of this method for the determination of OP residues in environmental samples at trace levels.

Monoclonal antibody-based ELISA for the quantification of nitrofuran metabolite 3-amino-2-oxazolidinone in tissues using a simplified sample preparation

A sensitive and specific monoclonal ELISA for the determination of tissue bound furazolidone metabolite 3-amino-2-oxazolidinone (AOZ) is described. The procedure enables the detection of AOZ in matrix supernatant after homogenisation, protease treatment, acid hydrolysis and derivatisation of AOZ released from the tissue by o-nitrobenzaldehyde. The formed p-nitrophenyl 3-amino-2-oxazolidinone (NPAOZ) is determined by ELISA calibrated with matrix-matched standards in the concentration range of 0.05-5.0 mu g l(-1). The assay was validated according to criteria set down by Commission Decision 2002/657/EC for the performance and validation of analytical methods for chemical residues. Detection capability, set on the basis of acceptance of no false negative results, was 0.4 mu g kg(-1) for shrimp, poultry, beef and pork muscle. This sensitivity approaches the established confirmatory LC-MS/MS able to quantify tissue-bound AOZ at levels as low as 0.3 mu g kg(-1). An excellent correlation of results obtained by ELISA and LC/MS-MS within the concentration range 0-32.1 mu g kg(-1) was found in the naturally contaminated shrimp samples (r = 0.999, n = 8). A similar con-elation was found for the incurred poultry samples within the concentration range of 0-10.5 mu g kg(-1) (r = 0.99, n = 8). (c) 2005 Elsevier B.V All rights reserved.

Production and characterisation of monoclonal antibodies for the detection of AOZ, a tissue bound metabolite of furazolidone

3-amino-2-oxazolidinone (AOZ) is a tissue bound toxic metabolite derived from the nitrofuran antibiotic, furazolidone. AOZ is detected in the derivatised form of 3-{[(2-nitrophenyl) methylene]amino}-2-oxazolidinone (NP AOZ). 3-{[( 3- carboxyphenyl)-methylene]amino-2-oxazolidinone (CP AOZ) was used as the immunising hapten for the production of monoclonal antibodies against NP AOZ. Monoclonal antibodies were produced using hybridomas from the fusion of murine myeloma cells and spleen cells isolated from BALB/c mice immunised with CP AOZ-ethylenediamine-human serum albumin (CP AOZ-ed-HSA). The antibody production in ascitic fluids from clones 3B8/2B9 and 2D11/A4 was monitored during a 16 month period. Repeated cultures of these hybridomas, followed by injection into mice and cloning did not change the assay parameters. Clone 2D11/A4 exhibited long term stability in antibody production throughout the experiment whereas clone 3B8/2B9 demonstrated variability in particular antibody yields whilst retaining assay sensitivity. Reasons for this production variability in clones are discussed. In an optimised direct ELISA format, the antibodies exhibited a 50% binding inhibition in the range of 0.52-1.15 ng/ml with NP AOZ (0.22-0.50 ng/ml, respective AOZ equivalents) and showed high specificity towards this analyte. The sensitivity of monoclonal antibodies incorporated into the ELISA is compatible with the European Union MRLP and is currently in use for routine analysis.

Immunochemical characterization of a polysaccharide antigen of Bacteroides fragilis with an IgM monoclonal antibody

An IgM mouse monoclonal antibody (McAb) Bf4 was produced to a surface polysaccharide of Bacteroides fragilis NCTC 9343. Immunoblotting showed that McAb Bf4 reacted strongly with a high molecular mass structure which was sensitive to oxidation with periodate but resisted protease treatment. An inhibition enzyme-linked immunosorbent assay (ELISA) indicated that McAb Bf4 did not cross react with the sixteen Bacteroides species and strains tested. Cells of B. fragilis NCTC 9343 recovered from the various interfaces of a Percoll discontinuous density gradient were tested in the inhibition ELISA. Bacteria from the 0-20%, 20-40% and 40-60% interfaces inhibited the ELISA; however, cells from the 60-80% interface did not. Electron microscopy with immunogold labelling showed that McAb Bf4 did not react with the extracellular fibrous network on bacteria recovered from the 0-20% interface, or the extracellular electron dense layer on cells from the 60-80% interface; however, it was associated with a surface structure on cells from the 20-40% interface. Growth in vivo did not enrich for bacteria with this structure.

Detection of intrastrain antigenic variation of Bacteroides fragilis surface polysaccharides by monoclonal antibody labelling

Bacteroides fragilis is a constituent of the normal resident microbiota of the human intestine and is the gram-negative obligately anaerobic bacterium most frequently isolated from clinical infection. Surface polysaccharides are implicated as potential virulence determinants. We present evidence of within strain immunochemical variation of surface polysaccharides in populations that are noncapsulate by light microscopy as determined by monoclonal antibody labelling. Expression of individual epitopes can be enriched from a population of an individual strain by use of immunomagnetic beads. Also, individual colonies in which either >94% or 94% of the bacteria carry a given epitope, there is no enrichment for other epitopes recognized by different polysaccharide-specific monoclonal antibodies. This intrastrain variation has important implications for the development of potential vaccines or immunodiagnostic tests.

Fasciola hepatica:development of monoclonal antibodies and their use to characterize a glycocalyx antigen in migrating flukes

Using mice harbouring early Fasciola hepatica infections, six monoclonal antibodies were prepared against a tegumental antigen present in T1 granules and glycocalyx of flukes. Blocking tests indicated that all monoclonals bound the same T1 epitope (or epitopes in close proximity on the antigen molecule), but this was not the determinant recognized by sheep and cattle. Localization of antibody binding at light and electron microscope levels showed that T1-type antigen also occurred in metacercarial tegument and in glycocalyx of gut cells and excretory ducts in juvenile and adult flukes. This indicates that the natural host-antibody response to F. hepatica may be to one antigen early in the infection. Protein A-gold labelling of monoclonal treated fluke sections revealed that the epitope was probably a polypeptide, unmodified by glycosylation in Golgi bodies. When isolated by immunoadsorption and separated electrophoretically under reducing conditions T1-type antigen was found to consist of a polypeptide mol. wt. 50 000, possibly linked to smaller entities mol. wt. 25-40 000. Tissue-specific variations in the antigen molecule might be conferred by linkage of different polypeptides or carbohydrate side-chains to an antigenic core polypeptide. A component of T1-type antigen was found to have mol. wt. of 25 000, possibly resembling a polypeptide of mol. wt. 24 000 from Schistosoma mansoni tegument.

Fasciola hepatica:studies on vaccination of rats and mice with a surface antigen prepared from fluke homogenate by means of a monoclonal antibody

T1 tegumental antigen was isolated from a homogenate of eight- to 10-week-old Fasciola hepatica using a T1-specific monoclonal antibody bound to sepharose in an antibody-affinity column. Rats and mice were vaccinated with T1 antigen in Freund's complete adjuvant, and control groups received equivalent amounts of non-T1 antigen (eluted from the antibody-affinity column) or ovalbumin. On completion of the immunisation programme, serum samples were collected for ELISA and IFA testing. The animals were challenged by oral infection with F hepatica metacercariae or, for several vaccinated rats, by intraperitoneal transplantation of live adult flukes. At autopsy, worm-burden and liver damage was assessed for each animal and the condition of transplanted flukes was examined. Comparison of test and control groups of animals showed that neither T1 nor non-T1 antigens provided significant protection against challenge, although specific antibody responses against the appropriate sensitising antigen were engendered. Flukes transplanted to the peritoneal cavity of immunised rats survived without damage, although they became encased in hollow fibrous capsules of host origin. The results lend support to the pre-existing concept that glycocalyx turnover by discharge of T1 secretory bodies at the apical surface of migrating flukes provides an efficient means of protection for the parasite against host immunity.

Fasciola hepatica:development of monoclonal antibodies against somatic antigens and their characterization by ultrastructural localization of antibody binding

A series of monoclonal antibodies was prepared against tegumental and internal antigens of Fasciola hepatica by immunizing mice with whole adult-fluke homogenates prior to harvesting the splenic lymphocytes for fusion. Preliminary screening by the Indirect Fluorescent Antibody technique indicated the occurrence of discrete groups of monoclonals differing from one another in tissue-specificity but within which IFA labelling patterns were fairly consistent. Representative hybridomas for 5 of these groups were stabilized and used to produce ascites fluid in mice. By application of an immunogold labelling technique it was possible to map the distribution of antigens for which each monoclonal antibody had affinity throughout the tissues of 4-week and 12-week flukes. Several monoclonals specifically labelled antigenic determinants on the important tegumental antigen T1. However the distribution of gold colloid labelling suggested that epitopes other than that normally exposed to the infected host were recognized; and several monoclonals specifically attached to T1 antigen in the tegument of juvenile worms only. The glycocalyx of the gut and excretory system of flukes shared T1 antigenicity with the tegument. Monoclonal antibodies were produced against an internal immunogen associated with ribosomes and heterochromatin in active protein-producing cells, and against interstitial material of adult flukes. Monoclonals against antigens in parenchymal cell cytoplasm and in mature vitelline cells were recognized but the corresponding hybridomas were not stabilized.

First development and characterisation of polyclonal and monoclonal antibodies to the emerging fresh water toxin cylindrospermopsin

As increasing incidences in the occurrence of cylindrospermopsin (CYN) appear, in addition to further research on its toxicological nature, improved rapid methods to detect this toxin are required. Antibody based assays are renowned for their ability to provide rapid, portable, simple to use tests. As yet however there are no publications outlining how an antibody to CYN can be produced. A range of chemical approaches was investigated to synthesise CYN immunogens for antibody production but failed to generate a response. Finally, a modified Mannich reaction for immunogen synthesis was employed to couple the toxin to two carrier proteins. Both protein conjugates were successfully used to raise both polyclonal and monoclonal antibodies of high sensitivity to CYN. These antibodies were characterised employing competitive indirect ELISA and an optical biosensor assay. By ELISA the sensitivity achieved ranged from 27 to 131. pg/mL and by SPR 4.4 to 11.1. ng/mL thus demonstrating that the selection of immunoassay platform is important for the detection level required by the end user for their application. Low cross-reactivity to the much less toxic metabolite deoxyCYN was observed. This is the first reported production of antibodies to this toxin. © 2013 Elsevier B.V.

Prior Autoimmune Disease and Risk of Monoclonal Gammopathy of Undetermined Significance and Multiple Myeloma:A Systematic Review

Background: Several observational studies have investigated autoimmune disease and subsequent risk of monoclonal gammopathy of undetermined significance (MGUS) and multiple myeloma. Findings have been largely inconsistent and hindered by the rarity and heterogeneity of the autoimmune disorders investigated. A systematic review of the literature was undertaken to evaluate the strength of the evidence linking prior autoimmune disease and risk of MGUS/multiple myeloma.

Methods: A broad search strategy using key terms for MGUS, multiple myeloma, and 50 autoimmune diseases was used to search four electronic databases (PubMed, Medline, Embase, and Web of Science) from inception through November 2011.

Results: A total of 52 studies met the inclusion criteria, of which 32 were suitably comparable to perform a meta-analysis. “Any autoimmune disorder” was associated with an increased risk of both MGUS [n = 760 patients; pooled relative risk (RR) 1.42; 95% confidence interval (CI), 1.14–1.75] and multiple myeloma (n>2,530 patients; RR 1.13, 95% CI, 1.04–1.22). This risk was disease dependent with only pernicious anemia showing an increased risk of both MGUS (RR 1.67; 95% CI, 1.21–2.31) and multiple myeloma (RR 1.50; 95% CI, 1.25–1.80).

Conclusions: Our findings, based on the largest number of autoimmune disorders and patients with MGUS/multiple myeloma reported to date, suggest that autoimmune diseases and/or their treatment may be important in the etiology of MGUS/multiple myeloma. The strong associations observed for pernicious anemia suggest that anemia seen in plasma cell dyscrasias may be of autoimmune origin.

Impact: Underlying mechanisms of autoimmune diseases, general immune dysfunction, and/or treatment of autoimmune diseases may be important in the pathogenesis of MGUS/multiple myeloma. Cancer Epidemiol Biomarkers Prev; 23(2); 332–42. ©2014 AACR.