Search results for: Immunoglobulin Reference Standard Whole Serum Host Mouse
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Investigation into the Antigenic Properties and Contributions to Growth in Blood of the Meningococcal Haemoglobin Receptors, HpuAB and HmbR.Acquisition of iron from host complexes is mediated by four surface-located receptors of Neisseria meningitidis. The HmbR protein and heterodimeric HpuAB complex bind to haemoglobin whilst TbpBA and LbpBA bind iron-loaded transferrin and lactoferrin complexes, respectively. The haemoglobin receptors are unevenly distributed; disease-causing meningococcal isolates encode HmbR or both receptors while strains with only HpuAB are rarely-associated with disease. Both these receptors are subject to phase variation and 70-90% of disease isolates have one or both of these receptors in an ON expression state. The surface-expression, ubiquity and association with disease indicate that these receptors could be potential virulence factors and vaccine targets. To test for a requirement during disease, an hmbR deletion mutant was constructed in a strain (MC58) lacking HpuAB and in both a wild-type and TbpBA deletion background. The hmbR mutant exhibited an identical growth pattern to wild-type in whole blood from healthy human donors whereas growth of the tbpBA mutant was impaired. These results suggest that transferrin is the major source of iron for N. meningitidis during replication in healthy human blood. To examine immune responses, polyclonal antisera were raised against His-tagged purified-recombinant variants of HmbR, HpuA and HpuB in mice using monolipopolysaccharide as an adjuvant. Additionally, monoclonal antibodies were raised against outer membrane loops of HmbR presented on the surface of EspA, an E. coli fimbrial protein. All antisera exhibited specific reactivity in Western blots but HmbR and HpuA polyclonal sera were reactive against intact meningococcal cells. None of the sera exhibited bactericidal activity against iron-induced wild-type meningococci. These findings suggest that the HmbR protein is not required during the early stages of disease and that immune responses against these receptors may not be protective.
2638 related Products with: Investigation into the Antigenic Properties and Contributions to Growth in Blood of the Meningococcal Haemoglobin Receptors, HpuAB and HmbR.FDA Standard Frozen Tissu FDA Standard Frozen Tissu FDA Standard Frozen Tissu FDA Standard Frozen Tissu Thermal Shaker with cooli FDA Standard Frozen Tissu FDA Standard Frozen Tissu Multiple organ tumor tiss MultiGene Gradient therm BACTERIOLOGY BACTEROIDES Human Insulin-like Growth Human Insulin-like Growth
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Mycobacterium tuberculosis antigen 85B and ESAT-6 expressed as a recombinant fusion protein in Mycobacterium smegmatis elicits cell-mediated immune response in a murine vaccination model.In this study, we investigated the potential molecular and immunological differences of a recombinant fusion protein (Hybrid-1), comprising of the immunodominant antigens Ag85B and ESAT-6 from Mycobacterium tuberculosis, derived from two different expression systems, namely Mycobacterium smegmatis and Escherichia coli. The fusion protein was successfully expressed and purified from both bacterial hosts and analyzed for any host-dependent post-translational modifications that might affect the immunogenicity of the protein. We investigated the immunogenicity of Hybrid-1 expressed in the two host species in a murine vaccination model, together with a reference standard Hybrid-1 (expressed in E. coli) from the Statens Serum Institut. No evidence of any post-translation modification was found in the M. smegmatis-derived Hybrid-1 fusion protein, nor were there any significant differences in the T-cell responses obtained to the three antigens analyzed. In conclusion, the Hybrid-1 fusion protein was successfully expressed in a homologous expression system using M. smegmatis and this system is worth considering as a primary source for vaccination trials, as it provided protein of excellent yield, stability and free from lipopolysaccharide.
2454 related Products with: Mycobacterium tuberculosis antigen 85B and ESAT-6 expressed as a recombinant fusion protein in Mycobacterium smegmatis elicits cell-mediated immune response in a murine vaccination model.Rabbit Anti-Cell death in Toxoplasma gondii GRA8, r FIV Core Ag, recombinant HIV 1 intergase antigen. Mycobacterium tuberculosi Rabbit Polyclonal to Myco Recombinant Human Interfe Recombinant Human Inhibin Recombinant Human Inhibin Cell Meter™ Intracellul Cell Meter™ Fluorimetri Cell Meter™ Fluorimetri
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A novel approach for the simultaneous quantification of a therapeutic monoclonal antibody in serum produced from two distinct host cell lines.Therapeutic monoclonal antibodies (mAbs) possess a high degree of heterogeneity associated with the cell expression system employed in manufacturing, most notably glycosylation. Traditional immunoassay formats used to quantify therapeutic mAbs are unable to discriminate between different glycosylation patterns that may exist on the same protein amino acid sequence. Mass spectrometry provides a technique to distinguish specific glycosylation patterns of the therapeutic antibody within the same sample, thereby allowing for simultaneous quantification of the same mAb with different glycosylation patterns. Here we demonstrate a two-step approach to successfully differentiate and quantify serum mixtures of a recombinant therapeutic mAb produced in two different host cell lines (CHO vs. Sp2/0) with distinct glycosylation profiles. Glycosylation analysis of the therapeutic mAb, CNTO 328 (siltuximab), was accomplished through sample pretreatment consisting of immunoaffinity purification (IAP) and enrichment, followed by liquid chromatography (LC) and mass spectrometry (MS). LC-MS analysis was used to determine the percentage of CNTO 328 in the sample derived from either cell line based on the N-linked G1F oligosaccharide on the mAb. The relative amount of G1F derived from each cell line was compared with ratios of CNTO 328 reference standards prepared in buffer. Glycoform ratios were converted to concentrations using an immunoassay measuring total CNTO 328 that does not distinguish between the different glycoforms. Validation of the IAP/LC-MS method included intra-run and inter-run variability, method sensitivity and freeze-thaw stability. The method was accurate (%bias range = -7.30-13.68%) and reproducible (%CV range = 1.49-10.81%) with a LOQ of 2.5 μg/mL.
2365 related Products with: A novel approach for the simultaneous quantification of a therapeutic monoclonal antibody in serum produced from two distinct host cell lines.FDA Standard Frozen Tissu FDA Standard Frozen Tissu Anti C Reactive Protein A MOUSE ANTI BOVINE ROTAVIR anti HSV (II) gB IgG1 (mo anti HCMV IE pp65 IgG1 (m anti HCMV gB IgG1 (monocl HIV1 integrase antibody, Human Serum Albumin antib Human Serum Albumin antib MOUSE ANTI BORRELIA BURGD FDA Standard Frozen Tissu
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Comparison of enzyme-linked immunosorbent assay and indirect fluorescent antibody test for the detection of IgG antibodies to Sarcocystis muris.Sarcocystis muris cystozoites were separated from host tissue after mechanical mincing and homogenization by discontinuous density gradient centrifugation using Percoll. The isolated antigen, consisting of more than 95% cystozoites, was used in an enzyme-linked immunosorbent assay (ELISA) and an indirect fluorescent antibody test (IFAT). In the ELISA, the antigen was used at a very low protein concentration of 0.44 micrograms/ml. Good reproducibility of test results was achieved with different conjugates and different reference sera when the measured optical densities were converted into an index related to a standard. From the examination of 500 sera from non-infected mice, and index of 0.300 at a serum dilution of 1:10 was determined as the threshold for a positive reaction in the ELISA. Specific antibodies were first detected between 18 and 49 days after experimental infection (dpi) with S. muris. The ELISA as well as the IFAT was highly sensitive from about 50 dpi onwards and detected antibodies up to the end of the examination period (182 dpi). However, the IFAT with unfixed antigen appeared more sensitive than the ELISA for the period of infection before 50 dpi and detected specific antibodies between 11 and 25 dpi starting with fluorescence at the apical pole of the cystozoite and resulting in bright fluorescence of the whole cystozoite from 32 or 35 dpi onwards. Both serotests showed only slight crossreactions with high titred Toxoplasma gondii sera at a serum dilution of 1:10. The activity of the antigen lasted for at least 13 months in the ELISA and for at least eight months in the IFAT.
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Physicochemical and serological characteristics of respiratory virus fluorescein-isothiocyanate conjugates for fluorescent-antibody diagnosis.Fluorescein-isothiocyanate (FITC) conjugates were prepared by improved methods from standard reference antisera to influenza A and B, mumps, parainfluenza 1, 2, 3, and 4, herpesvirus, respiratory syncytial virus, and adenovirus hexon. The antisera, prepared in a variety of animals, were fractionated three times with selected optimal concentrations of ammonium sulfate and yielded gamma globulins of adequate purity for conjugation with FITC. Conjugates containing optimal fluorescein-to-protein ratios of between 5 and 10 were produced in 2 h by dialysis labeling. Serological titers of each antiserum and conjugate were determined by complement fixation, hemagglutination-inhibition, serum neutralization, and indirect hemagglutination tests where appropriate. When corrected for dilution, the serological titers of the FITC conjugates were identical to those of the starting antisera. The fluorescent-antibody staining titers correlated well with one of the serological parameters of the original serum. The conjugates stained homologous antigens specifically and were free of nonspecific staining at the working dilution. Undesired staining of host cells which was a problem with some of the conjugates produced from sera containing cellular antibodies was removed by absorption with packed cells. These physicochemical and serological findings were then used as a guide in preparing high quality reagents for fluorescent-antibody identification of respiratory viruses.
2610 related Products with: Physicochemical and serological characteristics of respiratory virus fluorescein-isothiocyanate conjugates for fluorescent-antibody diagnosis.MOUSE ANTI CANINE DISTEMP Anti-Adenovirus Fluoresce Anti-Adenovirus Fluoresce Anti-BRSV(Bovine Respirat Anti-Bordetella pertussis MOUSE ANTI BOVINE ROTAVIR Monoclonal antibody Anti Measles Virus Nucleoprote Measles Virus nucleoprote Hepatitis C Virus antibod Feline Leukemia virus ant Feline Leukemia Virus p27
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