Littérature scientifique sur le sujet « Functional antibody titers »
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Articles de revues sur le sujet "Functional antibody titers"
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Schaller, Monica, Irmela Sulzer, Magnus Mansouri, MD student, Bernhard Lämmle et Johanna A. Kremer Hovinga Strebel. « Anti-ADAMTS13 Inhibitor Boosting During Plasma Exchange Therapy in Acquired TTP Is the Expression of a General Dysregulation of the Immune Response »,. Blood 118, no 21 (18 novembre 2011) : 3299. http://dx.doi.org/10.1182/blood.v118.21.3299.3299.
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Abstract Abstract 3299 Background. Thrombotic thrombocytopenic purpura (TTP) is a rare disorder characterized by thrombocytopenia, microangiopathic hemolytic anemia with schistocytes on the peripheral blood smear and a variable degree of ischemic organ dysfunction due to microvascular thrombosis. In the case of acquired TTP, circulating autoantibodies inhibit ADAMTS13 activity and/or increase ADAMTS13 clearance. The first-line treatment of an acute TTP bout is plasma exchange (PEX) therapy with the replacement of fresh frozen plasma. Up to 30% of TTP patients show an exacerbation under PEX. After initial improvement, platelet counts drop again which is typically associated with a strong increase of ADAMTS13 inhibitor titers, and therefore the phenomenon is also referred to as inhibitor boosting. Interestingly it is apparently not seen in other autoimmune diseases treated with PEX, like acquired hemophilia A or myasthenia gravis. The aim of this study was therefore to investigate if inhibitor boosting in acquired TTP is a general or ADAMTS13 specific phenomenon. Methods. Plasma samples, obtained day-to-day during PEX therapy supplemented with steroids until remission, of 9 patients suffering from acute TTP due to severe acquired ADAMTS13 deficiency, were analyzed for the following laboratory parameters: (a) C-reactive protein (CRP) and total IgG, (b) ADAMTS13 activity, (c) anit-ADAMTS13 antibody titers by ELISA, (d) functional inhibitor titers by FRETS assay, and (e) anti-TG and anti-TPO antibody titers. Results. At initial presentation inhibitor titers ranged from 0.7 - >10 BU/ml (a positive functional inhibitor titer is defined as >0.4 BU/ml by FRETS). All patients initially improved when PEX was started, however, in 7/9 cases a drop in platelet count was noted on day 7 (n=5), 8 or 9 (each n=1), which was associated with a substantial increase in anti-ADAMTS13 antibody and functional inhibitor titer in all seven patients. CRP was increased (>30mg/L) in one patient only, during the three days before the raise in inhibitor titer and a drop in platelet count was noted, while total IgG remained stable in all 9 patients throughout PEX. At presentation none of the patients had a positive result for the thyroid antibodies, however, all 9 patients developed positive anti-TPO antibody titers during treatment and three patients tested positive for anti-TG antibodies at the same time. Anti-TPO antibody peaks occurred after the anti-ADAMTS13 antibody peak in all patients (range days 9–17), except the two patients where no raise in anti-ADAMTS13 antibody titers was observed (anti-TPO peak on day 3 in both). The two patients without inhibitor boosting required only five and six PEX sessions, respectively to get into remission, of the other seven patients two didn't overcome the inhibitor boosting and became refractory and were subsequently successfully treated by splenectomy or Rituximab, and one patient died of sepsis on day 11. Conclusions. Inhibitor boosting in acquired TTP due to antibody-mediated severe ADAMTS1313 deficiency treated with PEX is common (78%) and cannot be overcome by standard first line treatment in half of the patients. The fact that significant titers of other autoantibodies than anti-ADAMTS13 antibodies occur during the acute disease episode is striking and points to a more general dysregulation of the immune response in acquired TTP. Investigation of further autoantibodies, cytokines, etc. to explore the role of B-cells and T-cells in this phenomenon in more detail are underway. Disclosures: No relevant conflicts of interest to declare.
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Plaimauer, Barbara, Claudia Juno et Friedrich Scheiflinger. « In Vitro Efficacy of Recombinant ADAMTS13 in Acquired TTP Patients with Anti-ADAMTS13 Inhibitory Antibody. » Blood 112, no 11 (16 novembre 2008) : 2295. http://dx.doi.org/10.1182/blood.v112.11.2295.2295.
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Abstract Thrombotic thrombocytopenic purpura (TTP) is associated with a severe functional deficiency of the ADAMTS13 metalloprotease resulting in accumulation of highly adhesive ultra-large von Willebrand factor (ULVWF) multimers. ULVWF promote spontaneous platelet clumping eventually leading to life-threatening widespread microvascular thrombosis in multiple organs. Inhibitory and non-inhibitory anti-ADAMTS13 autoantibodies that result in functional deficiency and/or accelerated in vivo clearance of ADAMTS13 have been detected in patients suffering from acquired idiopathic TTP. Current treatment with plasma exchange therapy is considered to remove the autoantibodies and to replenish plasma with the deficient protease. While researching therapeutic recombinant ADAMST13 (rADAMTS13) as a possible treatment modality for TTP patients, we investigated the in vitro potency of rADAMTS13 to overwhelm and neutralize circulating anti-ADAMTS13 antibodies and concurrently to reinstate plasma ADAMTS13 to normal. Mixing and incubating patient plasma with normal reagent plasma and subsequent FRETSVWF73 activity analysis was used to calculate the individual anti-ADAMTS13 inhibitor titers in 36 untreated idiopathic TTP patient plasma samples with severe ADAMTS13 deficiency (<10% of normal). The inhibitor titers (IU/ml) ranged from 1.5 to 85IU/ml (median of 3.75 IU/ml). To compare the performance of the different patient samples at equal inhibitor titers, we diluted each sample to predefined inhibitor titers (e.g. in patient samples with inhibitor titers <10IU/ml we diluted to 1, 3, 6 and 9IU/ml). Then, incrementally increasing concentrations of purified rADAMTS13 derived from stably transfected CHO cells were added to each pre-set inhibitor titer done for each of the 36 patient samples. Complex formation of rADAMTS13 and anti-ADAMTS13 patient antibody was allowed and the remaining ADAMTS13 activity was analyzed. The input of rADAMTS13 required to saturate circulating inhibitors and to elevate the activity level up to 1U/ml in the plasma was calculated by regression analysis. Our data indicate a linear correlation between supplemented rADAMTS13 and anti-ADAMTS13 antibody titer (for titers <10IU/ml) suggesting that rADAMTS13 should be further investigated as a possible treatment of acquired TTP.
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Tapia, Olga, Anatoly Slepenkin, Evgueni Sevrioukov, Kathi Hamor, Luis M. de la Maza et Ellena M. Peterson. « Inclusion Fluorescent-Antibody Test as a Screening Assay for Detection of Antibodies to Chlamydia pneumoniae ». Clinical and Vaccine Immunology 9, no 3 (mai 2002) : 562–67. http://dx.doi.org/10.1128/cdli.9.3.562-567.2002.
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ABSTRACT A study was conducted to determine the ability of the inclusion immunofluorescence assay (inclusion IFA) to act as a screening test to detect samples with antibodies to Chlamydia pneumoniae; microimmunofluorescence (MIF) was used as the “gold standard.” In addition, the inclusion IFA was compared using HEp-2 cells infected with either C. pneumoniae CM-1 or Chlamydia trachomatis serovar E. A total of 331 serum samples representing a range of MIF titers were evaluated. The sensitivities of the inclusion IFA for detecting samples with C. pneumoniae MIF titers of ≥16 were 96.9 and 74.8% with C. pneumoniae- and C. trachomatis-infected cells, respectively. For samples with an elevated C. pneumoniae MIF titer of ≥512, the sensitivities of the C. pneumoniae- and C. trachomatis-based inclusion IFA were 97.0 and 8.8%, respectively. These results suggest that the inclusion IFA is not a genus-specific test, as evidenced by the failure of the C. trachomatis-infected cells to detect a significant number of samples with C. pneumoniae antibodies. Samples that had elevated C. pneumoniae inclusion IFA and MIF titers but that were found negative (titer, <16) by the C. trachomatis inclusion IFA were further tested by an in vitro neutralization assay for functional antibodies that might not have been detected by the serological assays. The in vitro neutralization results corroborated the serological results in that all seven sera tested had a neutralization titer for C. pneumoniae (range, 20 to 225), while all but one failed to have any effect on the infectivity of C. trachomatis serovar E. While the C. pneumoniae inclusion IFA had a high sensitivity for detecting chlamydial antibodies, depending on whether it was used as a screening test for detecting samples with low (≥16) or elevated (≥512) MIF titers, its specificity ranged from 53.4 to 77.1%. In conclusion, the inclusion IFA with C. pneumoniae-infected cells was best suited as a sensitive screening test for identifying specimens with elevated MIF titers (those associated with a possible acute infection with C. pneumoniae).
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Oscherwitz, Jon, Fen Yu et Kemp B. Cease. « A Heterologous Helper T-Cell Epitope Enhances the Immunogenicity of a Multiple-Antigenic-Peptide Vaccine Targeting the Cryptic Loop-Neutralizing Determinant of Bacillus anthracis Protective Antigen ». Infection and Immunity 77, no 12 (5 octobre 2009) : 5509–18. http://dx.doi.org/10.1128/iai.00899-09.
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ABSTRACT We previously showed that a multiple antigenic peptide (MAP) displaying amino acids (aa) 305 to 319 from the 2β2-2β3 loop of protective antigen (PA) can elicit high-titered antibody that neutralizes lethal toxin (LeTx) in vitro and that this loop-neutralizing determinant (LND) specificity is absent in PA-immune rabbits. Some immune rabbits were, however, nonresponders to the MAP. We hypothesized that the immunogen elicited suboptimal major histocompatibility complex (MHC) class II-restricted T-cell help and that introduction of a functional helper T-cell epitope would increase MHC-restricted responsiveness and the magnitude and affinity of the antibody responses. In the current study, we characterized the T- and B-cell responses to LND peptides in mice, then designed second-generation MAP immunogens for eliciting LND-specific immunity, and tested them in rabbits. The 305-319 sequence was devoid of helper T-cell epitopes in three strains of mice; however, a T-B peptide comprising aa 305 to 319, colinearly synthesized with the P30 helper epitope of tetanus toxin, elicited robust LeTx-neutralizing immunity in mice. T-B MAPs displaying B-cell epitopes 304 to 319 (MAP304) or 305 to 319 (MAP305) elicited high-titer, durable antibody responses in rabbits which exhibited potent neutralization of LeTx in vitro. All MAP304-immune rabbits demonstrated neutralization titers exceeding that of hyperimmune sera of rabbits immunized with PA in Freund's adjuvant, with peak neutralization titers 23-, 6-, and 3-fold higher than that of the PA antiserum. Overall, immunization with MAPs containing the P30 epitope elicited higher antibody and toxin neutralization titers and peptide-specific affinity than immunization with an LND MAP lacking a helper epitope. P30-containing MAP304 represents a promising LND-specific vaccine for anthrax.
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Bash, Margaret C., Freyja Lynn, Brian Mocca, Ray Borrow, Helen Findlow, Musa Hassan-King, Marie-Pierre Preziosi et al. « Development and Use of a Serum Bactericidal Assay Using Pooled Human Complement To Assess Responses to a Meningococcal Group A Conjugate Vaccine in African Toddlers ». Clinical and Vaccine Immunology 21, no 5 (26 mars 2014) : 755–61. http://dx.doi.org/10.1128/cvi.00812-13.
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ABSTRACTA meningococcal group A polysaccharide (PS) conjugate vaccine (PsA-TT) has been developed for African countries affected by epidemic meningitis caused byNeisseria meningitidis. Complement-mediated serum bactericidal antibody (SBA) assays are used to assess protective immune responses to meningococcal vaccination. Human complement (hC′) was used in early studies demonstrating antibody-mediated protection against disease, but it is difficult to obtain and standardize. We developed and evaluated a method for sourcing hC′ and then used the SBA assay with hC′ (hSBA) to measure bactericidal responses to PsA-TT vaccination in 12- to 23-month-old African children. Sera with active complement from 100 unvaccinated blood donors were tested for intrinsic bactericidal activity, SBA titer using rabbit complement (rSBA), and anti-group A PS antibody concentration. Performance criteria and pooling strategies were examined and then verified by comparisons of three independently prepared hC′ lots in two laboratories. hSBA titers of clinical trial sera were then determined using this complement sourcing method. Two different functional antibody tests were necessary for screening hC′. hSBA titers determined using three independent lots of pooled hC′ were within expected assay variation among lots and between laboratories. In African toddlers, PsA-TT elicited higher hSBA titers than meningococcal polysaccharide or Hib vaccines. PsA-TT immunization or PS challenge of PsA-TT-primed subjects resulted in vigorous hSBA memory responses, and titers persisted in boosted groups for over a year. Quantifying SBA using pooled hC′ is feasible and showed that PsA-TT was highly immunogenic in African toddlers.
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Borrelli, Silvia, Rehana B. Hossany et B. Mario Pinto. « Immunological Evidence for Functional Rather than Structural Mimicry by a Shigella flexneri Y Polysaccharide-Mimetic Peptide ». Clinical and Vaccine Immunology 15, no 7 (7 mai 2008) : 1106–14. http://dx.doi.org/10.1128/cvi.00050-08.
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ABSTRACT An approach to vaccine design is the use of molecules that mimic the immunogenic element of interest. In this context, the interaction of MDWNMHAA, a peptide mimic of the Shigella flexneri Y O polysaccharide (PS), with an anti-carbohydrate monoclonal antibody, as studied previously by X-ray crystallography, suggested the presence of functional rather than structural mimicry and a bound peptide conformation that was not represented significantly in the free-ligand ensemble. The antibody response elicited by an MDWNMHAA-carrier protein (tetanus toxoid [TT]) conjugate has now been investigated in BALB/c mice. The mice were immunized following a homologous prime/boost strategy using MDWNMHAA-TT as the immunogen. The mice showed anti-peptide antibody (immunoglobulin G [IgG]) titers that increased after being boosted. High anti-lipopolysaccharide (LPS) (IgG) titers were observed after the last boost. A faster immune response, with cross-reactive titers, was observed with a peptide conjugate with 30% more copies of the peptide. The binding of anti-peptide polyclonal antibodies to LPS could be inhibited by LPS, PS, MDWNMHAA, and MDWNMHAA-bovine serum albumin, as assessed by inhibition enzyme-linked immunosorbent assay. Conversely, mice immunized with PS-TT showed IgG anti-peptide titers. These data demonstrate the cross-reactivity of the antibody response and support the hypothesis that functional, as opposed to structural, mimicry of the S. flexneri Y O PS by MDWNMHAA or the underrepresentation of the bound ligand conformation in the free-ligand ensemble does not compromise immunological cross-reactivity. Prime/boost strategies were performed with a heterologous boost of PS-TT or MDWNMHAA-TT. They led to high anti-LPS titers after only three injections, suggesting alternatives to improve the immunogenicity of the carbohydrate-mimetic peptide and confirming the antigenic mimicry.
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Gruenglas, Jeffrey, James Mond, Micaela Scobie, Cynthia Tolman et Joseph Martinez. « 10. Kinetics of Post-Vaccination Seroprotection to S. Pneumonia for the Immune-Compromised and Vaccine-Naïve Populations ». Open Forum Infectious Diseases 7, Supplement_1 (1 octobre 2020) : S27—S28. http://dx.doi.org/10.1093/ofid/ofaa439.055.
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Abstract Background S. pneumonia infection presents a significant challenge, accounting for 20–38% of hospital-acquired pneumonia, and the leading cause of community-acquired pneumonia despite availability of effective vaccines. Incidence is highest in children under 2 years, the immunocompromised, and elderly. CDC has reported the emergence of antibiotic resistance in ~30% of cases, adding to risk of morbidity and mortality. Fewer than half of the elderly are vaccinated and vulnerable to infection on admission. Passive immunotherapy as an adjunct to vaccines may improve outcomes in such populations. The objective of this study was to evaluate whether seroprotective response induced with a pneumococcal conjugate vaccine could rapidly yield protective opsonic levels of antibody within anticipated duration of hospitalization. Methods Healthy donors (n=30) were immunized with Prevnar. Blood was drawn on days 0, 3, 7, 10, 14, 21, and 28. Samples were pooled and tested for presence of functional opsonic antibodies recognizing capsular polysaccharides. Clearance mechanism of S. pneumonia was based on antibody recognition to pneumococcal capsular polysaccharide and opsonic titers used as an in vitro surrogate to evaluate the efficacy of vaccine. Results There was little to no opsonic activity against most serotypes on day 0, except for low antibody activity with serotypes 1, 3, 4, and 5. Titers increased, with protective levels achieved by day 10 for most serotypes (except 14 and 18C), peaking at day 14 or after across serotypes (Figures 1 and 2). Average titers rose from log2 titer 2 on day 0 to log2 titer 8 on days 21 and 28. Titers against most serotypes reached log2 10 (titer 1024) or higher. Patients remained susceptible to nosocomial infection for at least 10 days post admission until protective titers are reached. OPK titers (log2 scale) for serum samples on day 0 (pre), day 3, 7, 10, 14, 21, 28, and control for S. pneumoniae serotypes 1, 3, 4, 5, 6A, 6B, 7F, 9V. N=2. OPK titers (log2 scale) for serum samples on day 0 (pre), day 3, 7, 10, 14, 21, 28, and control for S. pneumoniae serotypes 14, 18C, 19A, 19F, and 23F. N=2. Conclusion Patients with no prior history of vaccination (or inability to mount response) with Prevnar or pneumovax remain vulnerable to S. pneumonia infection even if vaccinated on entry, due to delayed kinetics in reaching protective titers. These patients may require prophylactic intervention of hyperimmune Ig with high opsonic titers to S. pneumonia, providing protection until vaccine response elicits protective antibodies. Disclosures All Authors: No reported disclosures
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Martinez, Joseph, Tamara Pilishvili, Suzanne Barnard, Joseph Caba, Willie Spear, Sandra Romero-Steiner et George M. Carlone. « Opsonophagocytosis of Fluorescent Polystyrene Beads Coupled to Neisseria meningitidis Serogroup A, C, Y, or W135 Polysaccharide Correlates with Serum Bactericidal Activity ». Clinical and Vaccine Immunology 9, no 2 (mars 2002) : 485–88. http://dx.doi.org/10.1128/cdli.9.2.485-488.2002.
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ABSTRACT We developed a polysaccharide-specific flow cytometric opsonophagocytic assay (OPA) for the simultaneous measurement of functional antibody to Neisseria meningitidis serogroups A, C, Y, and W135. OPA titers significantly correlated with serum bactericidal assay titers for all serogroups tested (mean r = 0.96; P < 0.001). OPA could be used in meningococcal vaccine evaluation.
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Balingit, Jean Claude, Minh Huong Phu Ly, Mami Matsuda, Ryosuke Suzuki, Futoshi Hasebe, Kouichi Morita et Meng Ling Moi. « A Simple and High-Throughput ELISA-Based Neutralization Assay for the Determination of Anti-Flavivirus Neutralizing Antibodies ». Vaccines 8, no 2 (10 juin 2020) : 297. http://dx.doi.org/10.3390/vaccines8020297.
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Mosquito-borne flavivirus infections, including dengue virus and Zika virus, are major public health threats globally. While the plaque reduction neutralization test (PRNT) is considered the gold standard for determining neutralizing antibody levels to flaviviruses, the assay is time-consuming and laborious. This study, therefore, aimed to develop an enzyme-linked immunosorbent assay (ELISA)-based microneutralization test (EMNT) for the detection of neutralizing antibodies to mosquito-borne flaviviruses. The inhibition of viral growth due to neutralizing antibodies was determined colorimetrically by using EMNT. Given the significance of Fcγ-receptors (FcγR) in antibody-mediated neutralization and antibody-dependent enhancement (ADE) of flavivirus infection, non-FcγR and FcγR-expressing cell lines were used in the EMNT to allow the detection of the sum of neutralizing and immune-enhancing antibody activity as the neutralizing titer. Using anti-flavivirus monoclonal antibodies and clinical samples, the utility of EMNT was evaluated by comparing the end-point titers of the EMNT and the PRNT. The correlation between EMNT and PRNT titers was strong, indicating that EMNT was robust and reproducible. The new EMNT assay combines the biological functional assessment of virus neutralization activity and the technical advantages of ELISA and, is simple, reliable, practical, and could be automated for high-throughput implementation in flavivirus surveillance studies and vaccine trials.
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Miura, Kazutoyo, Mahamadou Diakite, Samuel Moretz, Hong Zhou, Ababacar Diouf, Gregory Tullo, Tatiana Lopera-Mesal, Jennifer Anderson, Rick Fairhurst et Carole Long. « Impact of sickle-cell trait on humoral immunity against Plasmodium falciparum in children living in malaria endemic areas of Mali (45.10) ». Journal of Immunology 184, no 1_Supplement (1 avril 2010) : 45.10. http://dx.doi.org/10.4049/jimmunol.184.supp.45.10.
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Abstract Previous studies have shown that children with sickle-cell trait (heterozygosity for normal hemoglobin A and sickle hemoglobin S, genotype AS) are resistant to P. falciparum malaria when compared with AA children. Passive transfer studies have established the importance of antibodies against blood-stage parasites. However, the impact of sickle-cell trait on immunity against parasite antigens has not been extensively studied. In a longitudinal study in rural Mali, we followed 73 AS and 126 AA children for an entire 6-month transmission season. Before the transmission season, antibody titers were measured against 4 parasite blood-stage antigens (AMA1, MSP1, EBA175 and MSP2). AS children experienced significantly fewer malaria episodes than AA children. Because there is a significant effect of age on antibody titers, we stratified children in 3 age groups (3-5, 6-8 and 9-11 years). Compared to AA children aged 9-11 years, AS children showed significantly lower antibody titers to all 4 antigens. For the 6-8 years group, AS children showed significantly lower antibody titers to EBA175 and MSP2. No differences were observed between AA and AS children 3-5 years old for any antigen. These data suggest that the antibody titers against these major blood-stage antigens before transmission season are not involved in reducing the incidence of malaria in AS children. The functional activity of antibodies (i.e., in vitro parasite growth-inhibitory activity) will be also presented.
Thèses sur le sujet "Functional antibody titers"
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MORASCHINI, LUCA. « Likelihood free and likelihood based approaches to modeling and analysis of functional antibody titers with applications to group B Streptococcus vaccine development ». Doctoral thesis, Università degli Studi di Milano-Bicocca, 2015. http://hdl.handle.net/10281/76794.
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Opsonophagocytic killing assays (OPKA) are routinely used for the quantification of bactericidal antibodies against Gram-positive bacteria in clinical trial samples. The OPKA readout, the titer, is traditionally estimated using non-linear dose-response regressions as the highest serum dilution yielding a predefined threshold level of bacterial killing. Therefore, these titers depend on a specific killing threshold value and on a specific dose-response model. This thesis describes a novel OPKA titer definition, the threshold free titer, which preserves biological interpretability whilst not depending on any killing threshold. First, a model-free version of this titer is presented and shown to be more precise than the traditional threshold-based titers when using simulated and experimental group B Streptococcus (GBS) OPKA experimental data. Second, a model-based threshold-free titer is introduced to automatically take into account the potential saturation of the OPKA killing curve. The posterior distributions of threshold-based and threshold-free titers is derived for each analysed sample using importance sampling embedded within a Markov chain Monte Carlo sampler of the coefficients of a 4PL logistic dose-response model. The posterior precision of threshold-free titers is again shown to be higher than that of threshold-based titers. The biological interpretability and operational characteristics demonstrated here indicate that threshold-free titers can substantially improve the routine analysis of OPKA experimental and clinical data.
Chapitres de livres sur le sujet "Functional antibody titers"
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Sandbulte, Matthew R., et Maryna C. Eichelberger. « Analyzing Swine Sera for Functional Antibody Titers Against Influenza A Neuraminidase Proteins Using an Enzyme-Linked Lectin Assay (ELLA) ». Dans Methods in Molecular Biology, 337–45. New York, NY : Springer New York, 2014. http://dx.doi.org/10.1007/978-1-4939-0758-8_28.
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McCarter, Stuart J., et Andrew McKeon. « Behavioral Change, Seizures, and Temporal Lobe Lesion ». Dans Mayo Clinic Cases in Neuroimmunology, sous la direction de Andrew McKeon, B. Mark Keegan et W. Oliver Tobin, 204–6. Oxford University Press, 2021. http://dx.doi.org/10.1093/med/9780197583425.003.0066.
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A 56-year-old man with a history of type 2 diabetes, hypertension, hyperlipidemia, sleep apnea, alcohol use disorder in remission, renal cell carcinoma, and mucinous adenocarcinoma of the lung sought care for evaluation of presumed limbic encephalitis. Six months before evaluation, he had development of anxiety, fatigue, and blurry vision. He was diagnosed with renal cell carcinoma, which was resected. Subsequently, worsening depression developed, which required self-admitted psychiatric hospitalization for suicidal ideation. After discharge he had subacute development of aphasia, inability to recognize family members, and delusions for which he was hospitalized. Brain magnetic resonance imaging demonstrated a large, partly expansile, T2/fluid-attenuated inversion recovery–hyperintense lesion involving the left hippocampus and parahippocampal gyrus, as well as temporal neocortex and white matter, which was interpreted as limbic encephalitis. Spinal fluid analysis showed 66 total nucleated cells/μL with 93% lymphocytes, normal cytologic findings, protein concentration of 66 mg/dL, and 15 erythrocytes/μL. The Kokmen short test of mental status indicated mainly an amnestic profile without delirium, with a total score of 31 of 38. Given the patient’s neuroimaging findings for limbic encephalitis and lack of clear encephalopathy, the initial focus was confirming or ruling out the diagnosis of limbic encephalitis. He underwent repeated cerebrospinal fluid analysis, which showed 3 total nucleated cells/μL with a protein concentration of 67 mg/dL. Serum autoantibody testing showed a low-titer glutamic acid decarboxylase 65-kDa isoform antibody value of 0.17 nmol/L. Brain magnetic resonance imaging 3 months after his initial magnetic resonance imaging showed slight progression of the expansile, left temporal lobe, T2-hyperintense lesion, further involving the left parietal lobe white matter, temporal lobe neocortex, and splenium of the corpus callosum, without clear gadolinium enhancement. A diagnosis of anaplastic astrocytoma (World Health Organization grade III) was made. He was treated with temozolomide and radiotherapy, with radiographic improvement. However, he had development of medically refractory focal seizures with secondary generalization. Approximately 3 years after his initial diagnosis, the patient experienced functional decline, with brain magnetic resonance imaging demonstrating multiple new, bihemispheric, T2-hyperintense lesions concerning for multifocal glioma. Given his poor prognosis and functional status, the patient was transitioned to comfort care. The presentation of disease in this patient highlights the importance of neuroimaging interpretation in the context of clinical history. Although this case patient had some features that could suggest a paraneoplastic limbic encephalitis—including behavioral changes, seizure, systemic malignancy, and apparent clinical response to immunosuppression—several features were inconsistent with this diagnosis.
Actes de conférences sur le sujet "Functional antibody titers"
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de Serres, M., H. M. Reisner, D. Monroe et H. Roberts. « A MONOCLONAL ANTIBODY WHOSE BINDING IS INHIBITED BY DIVALENT CATIONS ». Dans XIth International Congress on Thrombosis and Haemostasis. Schattauer GmbH, 1987. http://dx.doi.org/10.1055/s-0038-1644075.
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Factor IX (FIX), a vitamin K dependent coagulation protein, is functionally deficient or absent in patients with hemophilia B. Binding of Ca++ by the gammacarboxyglutamic acid residues (Gla) of FIX is necessary for coagulant activity. Antibodies havebeendes-cribed which selectively bind to FIX in the presence of Ca++ and appear to interact with Ca-H- stabilized epitopes of FIX. One IgM, Kappa murine monoclonal antibody (Mab), 129-1, has been found to react preferentially with FIX in the absence of Ca-H- or with FIX having a reduction in gammacarboxylation. 129-1 was characterized by direct binding ELISA assays, the standard assay buffer (.02M Tris - .15M NaCL pH 7.5) was supplemented with Ca-H- or ED TA to final concentrations to 5mM and lOmM respectively. In the presence of Ca-H-, titers ranged from 10 to 100 as compared to 100 K to 500 K in the presence of EDTA. Control Mab's, FIX-30 and 2D521 showed no such effect. Maximum inhibition occurred ≥2.5 mM Ca-H- concentration. Mg++, Sr-H- and Mn-H- were tested with similar results. Chemically degammacarboxylated FIXa was compared to FIX and FIXa controls in the presence of Ca-H- or EDTA, to determine the importance of Gla residues. In the presence of EDTA, Mab 129-1 had essentially equal reactivity with all these proteins (titers 100 K). In the presence of Ca-H-, binding to FIX and FIXa was inhibited (500 and 1 K respectively). However, the binding to Gla modified FIXa in the presence of Ca-H- was only slightly reduced (10 K), suggesting the importance of Gla residues in the Ca-H- mediated inhibition. FIX was purified from concentrate, coumadinized plasma and culture supernatant (produced in the absence of vitamin K) from the cell line PMN45 using HPLC affinity chromatography with Mab 2D521. Mab 129-1 binding to FIX immunopurified from concentrate and a control biochemically purified FIX protein preparation was significantly higher in the presence of EDTA (titers 500 and 5 K) than in Ca-H- (titers 10 and 10). FIX purified from coumadinized plasma or PMN45 cells showed equal low reactivity with 129-1 in the presence or absence of Ca-H- (titer 10 in all cases). FIX-30 and 2D521 controls showed no such reduction in binding. Therefore, Gla residues may play a role in the binding of 129-1 to FIX.
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Wernet, P., M. Haurand, W. Nüsing, E. M. Schneider, K. Jaschonek et V. Ullrich. « Production and characterization of a murine monoclonal antibody against human thromboxane synthetase ». Dans XIth International Congress on Thrombosis and Haemostasis. Schattauer GmbH, 1987. http://dx.doi.org/10.1055/s-0038-1643382.
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Eicosanoids appear to have an important role in the actual momentary regulation of tissue blood flow. The function of constricting blood vessels by affecting the vascular tone has been assigned to thromboxane. Thromboxane synthetase, the enzyme responsible for the conversion of Prostaglandin-H2 into thromboxane A2, has been shown to be present in platelets, lung fibroblasts and the brain. Recently, thromboxane synthetase has been totally purified. The enzyme isolated from platelets appears to have a molecular weight of 58,800 Dalton and to belong to the group of cytochrome P450 proteins. In order to make a monoclonal antibody against thromboxane synthetase, BALB/c mice were injected four times i.m. with 10, 5, 5 and 4 μg of the platelet purified enzyme in complete Freund's adjuvant. The serum antibody titer against thromboxane synthetase in an ELISA was higher than 1:1000 after the second boost. One mouse received a fifth i.v. injection of 10 μg of the purified enzyme. One monoclonal antibody of the several hundreds of hybridomas screened in an ELISA revealed specific activity against thromboxane synthetase with a titer of 1:512 present in the culture supernatant. After recloning this reagent, called T0300, was used for the preparation of an immunoaffinity column, where it also reacted specifically. In immunoprecipitation experiments T0300 was able to precipitate a 58,000 D molecule. Also the biological activity of thromboxane synthetase could be blocked by monoclonal antibody T0300. In addition this reagent was employed in indirect immunofluorescence on leukemic cells employing a FACS IV cytofluorometer. Here specific staining of two megacaryocytic blast cell populations could be demonstrated. Thus T0300 appears to be a monoclonal antibody against human thromboxane synthetase.
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Bonella, Francesco, Yan Lyu, Ulrich Costabel, MIchael Kreuter, Josune Guzman, Eda Boerner, Dirk Theegarten et Thomas Wessendorf. « Serum anti DFS70 antibody titer and lung functional impairment in patients with interstitial lung disease (ILD) ». Dans ERS International Congress 2017 abstracts. European Respiratory Society, 2017. http://dx.doi.org/10.1183/1393003.congress-2017.pa900.
Texte intégral
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Damasceno Júnior, Eustáquio Costa, Isabella Sabião Borges, João Victor Aguiar Moreira, Pedro Otávio Rego de Aguiar, Thaciany Soares Ferreira, Leonardo Peixoto Garcia, Glauber Mota Pacheco et al. « Successful treatment with rituximab in a refractory Stiffperson syndrome (SPS) ». Dans XIII Congresso Paulista de Neurologia. Zeppelini Editorial e Comunicação, 2021. http://dx.doi.org/10.5327/1516-3180.507.
Texte intégralRésumé :
Background: SPS is a disorder consisting of rigidity of axial muscles with painful spasms. More than 80 % of SPS patients have high titer antibodies against glutamic acid decarboxylase (GAD). The use of rituximab for the treatment of SPS is a recent therapeutical approach showing promising results. We present a case of SPS treated with rituximab, showing a good and safe response. Case: A 38-year-old female patient presented with a history of rigidity of abdominal and paravertebral muscles associated with painful spasms in lower back region, increased tonus, lumbar lordosis, frequent falls and severe functional limitation. The anti-GAD antibodies were positive in high titles. Electromyography showed continuous motor activity with normal morphology especially on paravertebral muscles. She had a partial response to baclofen and diazepam, but could not tolerate it because of somnolence, and started the treatment with rituximab. After one year, the baclofen was discontinued and the diazepam reduced. The axial stiffness and spasm frequency improved, including postural instability, without new episodes of falls. Discussion: Rituximab is a monoclonal antibody targeting the CD20 antigens on the surface of mature B lymphocytes. After binding to these antigens, it initiates a cascade of biochemical events leading to apoptosis. Its use has been approved for numerous diseases with promising results. The use of rituximab in the treatment of SPS is a recent approach and good results have been reported. Conclusion: Rituximab may be a promising option in SPS treatment. However, this is a preliminary paper showing partial results requiring long-term follow-up.
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Schorer, Anna E., et Kathleen V. Watson. « THE "LUPUS ANTICOAGULANT" INDUCES FUNCTIONAL CHANGES IN ENDOTHELIAL CELLS AND PLATELETS ». Dans XIth International Congress on Thrombosis and Haemostasis. Schattauer GmbH, 1987. http://dx.doi.org/10.1055/s-0038-1643656.
Texte intégralRésumé :
The presence of the "lupus anticoagulant" (LA) predicts a clinical syndrome of excessive arterial, venous and microvascu-lar thrombosis. LA is an antibody which reacts with negatively charged phospholipid (PL) species in vitro. Since PL is involved in many aspects of the regulation of thrombosis, we postulated that LA might modify one or more of the membrane-(PL-dependent reactions of platelets and endothelial cells (EC). Blood samples from 20 patients with a history of thrombosis were tested for the presence of LA (kaolin PTT) and titres determined. LA-positive (LA+) sera and plasma were compared to LA-negative (LA−) samples from normal donors (n=6) or patients who had lupus but no clinical thrombosis (n=4). These specimens were tested in a panel of assays. The thrombin-stimulated release of prostacyclin (PG12) from cultured human EC was markedly reduced (52%±12.5 s.e.) by preincubation of the EC with LA+ sera (30 minutes). Purified LA+ IgG from one patient reproduced this effect. Thrombin induction of EC synthesis of the procoagulant, tissue factor-which is dissociable from prostaglandin metabolism-was also inhibited by LA+ sera. Normal platelets incubated in LA+ plasma became refractory to thrombin (1 unit/ml) but retained their responsiveness to epinephrine and ADP. The reduced responsiveness to thrombin was not due to altered (specific or total) binding of thrombin. The cleavage of Factor X by Factor VII requires PL as a co-factor for the EC procoagulant, tissue factor (TF). Unlike the inhibitory effect of LA on thrombin activation of EC and platelets, this distinct membrane-(PL-) dependent function was variably enhanced by LA+ sera. Brief (20 min) exposure of EC to LA+ sera increased TF co-catalysis of Factor VII cleavage of Factor X (measured by chromogenic Xa substrate, S-2222) by up to 10 fold (p<0.05, unpaired t test). This effect was not the result of EC disruption or changes in whole-cell TF content. These data suggest multiple, complex and heterogenous effects of LA, including impaired production of PG12, impaired EC modulation, and heightened ability of endogenous EC tissue factor to initiate coagulation. These (and perhaps other) membrane-dependent effects may contribute to the tendency of LA+ patients to develop clots.
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Fulcher, C. A., R. A. Houghten, S. de Graaf Mahoney, J. R. Roberts et T. S. Zimmerman. « SYNTHETIC PEPTIDE PROBES OF FACTOR VIII IMMUNOLOGY AND FUNCTION ». Dans XIth International Congress on Thrombosis and Haemostasis. Schattauer GmbH, 1987. http://dx.doi.org/10.1055/s-0038-1644768.
Texte intégralRésumé :
In order to develop specific immunologic reagents for mapping functionally important sites on FVIII, we have prepared rabbit polyclonal antibodies against synthetic peptides of FVIII derived from regions along the entire FVIII amino acid sequence. To date, a total of 70 peptides have been synthesized and characterized by amino acid and HPLC analysis. The peptides were coupled to keyhole limpet hemocyanin with glutaraldehyde as a linkage reagent and used to immunize rabbits. Antisera were tested by ELISA assay on polystyrene microtiter plates coated with either the peptide immunogen, or purified FVIII. The antisera were also tested for their ability to inhibit FVIII clotting activity and to react with separated FVIII polypeptides on immunoblots.Of the 70 peptides, all reacted with the peptide immunogen, 45 reacted with purified FVIII and 33 reacted with FVIII on immunoblots. Because we had obtained evidence that cleavage of the amino terminal region of the 80 kDa polypeptide may play a role in FVIII activation by thrombin, a series of partially overlapping peptides, 15 residues in length, were synthesized in this area. After affinity purifying these antibodies on columns of FVIII immobilized on agarose, adjusting the antibodies to equal antigen binding titers by dot immunoblotting and testing for inhibition of FVIII activity, only one antibody could strongly inhibit FVIII clotting activity. This inhibition could be blocked by the peptide itself at nanomolar concentrations and no significant inhibition could be shown by antibodies to partially overlapping peptides individually, or in combination. These data suggest that a site important to FVIII function can be localized to a 15 amino acid residue region of the 80 kDa polypeptide of FVIII. In addition, a second inhibitoryantibody was identified which was produced against a peptide in the carboxy terminal region of the 54 kDa thrombin fragment of FVIII and this area is currently being studied in a similar manner. In addition, two monoclonal anti-FVIII synthetic peptide antibodies have been produced which react with purified FVIII on immunoblots. One of these antibodies also functions as an immunoadsorbent when linked to agarose and FVII can be purified in this manner, using the synthetic peptide as eluant. It is evident that antibodies to synthetic peptides of FVIII can be useful probes of FVIII structure, function and interactions as well as being of use in FVIII purification.
Rapports d'organisations sur le sujet "Functional antibody titers"
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Eldar, Avigdor, et Donald L. Evans. Streptococcus iniae Infections in Trout and Tilapia : Host-Pathogen Interactions, the Immune Response Toward the Pathogen and Vaccine Formulation. United States Department of Agriculture, décembre 2000. http://dx.doi.org/10.32747/2000.7575286.bard.
Texte intégralRésumé :
In Israel and in the U.S., Streptococcus iniae is responsible for considerable losses in various fish species. Poor understanding of its virulence factors and limited know-how-to of vaccine formulation and administration are the main reasons for the limited efficacy of vaccines. Our strategy was that in order to Improve control measures, both aspects should be equally addressed. Our proposal included the following objectives: (i) construction of host-pathogen interaction models; (ii) characterization of virulence factors and immunodominant antigens, with assessment of their relative importance in terms of protection and (iii) genetic identification of virulence factors and genes, with evaluation of the protective effect of recombinant proteins. We have shown that two different serotypes are involved. Their capsular polysaccharides (CPS) were characterized, and proved to play an important role in immune evasion and in other consequences of the infection. This is an innovative finding in fish bacteriology and resembles what, in other fields, has become apparent in the recent years: S. iniae alters surface antigens. By so doing, the pathogen escapes immune destruction. Immunological assays (agar-gel immunodiffusion and antibody titers) confirmed that only limited cross recognition between the two types occurs and that capsular polysaccharides are immunodominant. Vaccination with purified CPS (as an acellular vaccine) results in protection. In vitro and ex-vivo models have allowed us to unravel additional insights of the host-pathogen interactions. S. iniae 173 (type II) produced DNA fragmentation of TMB-8 cells characteristic of cellular necrosis; the same isolate also prevented the development of apoptosis in NCC. This was determined by finding reduced expression of phosphotidylserine (PS) on the outer membrane leaflet of NCC. NCC treated with this isolate had very high levels of cellular necrosis compared to all other isolates. This cellular pathology was confirmed by observing reduced DNA laddering in these same treated cells. Transmission EM also showed characteristic necrotic cellular changes in treated cells. To determine if the (in vitro) PCD/apoptosis protective effects of #173 correlated with any in vivo activity, tilapia were injected IV with #173 and #164 (an Israeli type I strain). Following injection, purified NCC were tested (in vitro) for cytotoxicity against HL-60 target cells. Four significant observations were made : (i) fish injected with #173 had 100-400% increased cytotoxicity compared to #164 (ii) in vivo activation occurred within 5 minutes of injection; (iii) activation occurred only within the peripheral blood compartment; and (iv) the isolate that protected NCC from apoptosis in vitro caused in vivo activation of cytotoxicity. The levels of in vivo cytotoxicity responses are associated with certain pathogens (pathogen associated molecular patterns/PAMP) and with the tissue of origin of NCC. NCC from different tissue (i.e. PBL, anterior kidney, spleen) exist in different states of differentiation. Random amplified polymorphic DNA (RAPD) analysis revealed the "adaptation" of the bacterium to the vaccinated environment, suggesting a "Darwinian-like" evolution of any bacterium. Due to the selective pressure which has occurred in the vaccinated environment, type II strains, able to evade the protective response elicited by the vaccine, have evolved from type I strains. The increased virulence through the appropriation of a novel antigenic composition conforms with pathogenic mechanisms described for other streptococci. Vaccine efficacy was improved: water-in-oil formulations were found effective in inducing protection that lasted for a period of (at least) 6 months. Protection was evaluated by functional tests - the protective effect, and immunological parameters - elicitation of T- and B-cells proliferation. Vaccinated fish were found to be resistant to the disease for (at least) six months; protection was accompanied by activation of the cellular and the humoral branches.
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David, Lior, Yaniv Palti, Moshe Kotler, Gideon Hulata et Eric M. Hallerman. Genetic Basis of Cyprinid Herpes Virus-3 Resistance in Common Carp. United States Department of Agriculture, janvier 2011. http://dx.doi.org/10.32747/2011.7592645.bard.
Texte intégralRésumé :
The goal of this project was to provide scientific and technical basis for initiating the development of breeding protocols using marker assisted selection for viral disease resistance in common carp. The specific objectives were: 1) Establishing families and characterizing the phenotypic and genetic variation of viral resistance; 2) Measuring the dynamics of immune response and developing a method to measure the long term immune memory; 3) Developing markers and generating a new genetic linkage map, which will enable initial QTL mapping; and, 4) Identifying genetic linkage of markers and candidate genes (like MHC and TLRs) with resistance to CyHV-3. The common carp is an important farmed freshwater fish species in the world. Edible carp is second only to tilapia in Israeli aquaculture production and ornamental carp (koi) is an important product in both the US and Israel. Carp industries worldwide have recently suffered enormous economic damage due to a viral disease caused by Cyprinid herpes virus 3 (CyHV-3). Aside from preventative measures, a sustainable solution to this problem will be to establish a genetic improvement program of the resistance of fish to the pathogen. The aims of the project was to take the necessary first steps towards that. The differences in survival rates after infection with CyHV-3 virus among 20 families from six types of crosses between three carp lines (two commercial lines and one wild-type carp) revealed that the wild-type carp and its crosses had a much-improved survival over the crosses of the commercial lines themselves. These crosses set the starting point for breeding of commercial strains with improved resistance. Resistant fish had lower antibody titer against the virus suggesting that resistance might depend more on the innate immunity. A set of 500 microsateliite markers was developed and the markers are currently being used for generating a genetic linkage map for carp and for identifying disease resistance QTL. Fourteen candidate immune genes, some of which were duplicated, were cloned from the carp and SNP markers were identified in them. The expression of these genes varied between tissues and suggested functional divergence of some duplicated genes. Initial association between CyHV-3 resistance and one of the genes was found when SNP alleles in these genes were tested for their segregation between susceptible and resistant progeny. The results of this project have implications to the development of viral resistant commercial carp strains and effective immunization against this aggressive disease. The genetic and immunological knowledge accumulated in this project will not only promote carp and koi production but will also contribute to a broader understanding of fish immunogenetics.