Specificity of the enzyme-linked immunosorbent assay (ELISA) for Toxoplasma IgG antibody

1984 ◽  
Vol 78 (5) ◽  
pp. 661-662 ◽  
Author(s):  
R.J. Dahl ◽  
Alan M. Johnson
Keyword(s):  
Immunosorbent Assay ◽  
Enzyme Linked Immunosorbent Assay ◽  
Igg Antibody

scholarly journals Development and Validation of 13-plex Luminex-Based Assay for Measuring Human Serum Antibodies to Streptococcus pneumoniae Capsular Polysaccharides

mSphere ◽  
2018 ◽  
Vol 3 (4) ◽  
pp. e00128-18 ◽  
Author(s):  
Danka Pavliakova ◽  
Peter C. Giardina ◽  
Soraya Moghazeh ◽  
Shite Sebastian ◽  
Maya Koster ◽  
...  
Keyword(s):  
Human Serum ◽  
Lower Limit ◽  
Immunosorbent Assay ◽  
Enzyme Linked Immunosorbent Assay ◽  
Igg Antibodies ◽  
Igg Antibody ◽  
Correlate Of Protection ◽  
Immune Correlate ◽  
Relative Standard ◽  
Limit Of Quantitation

ABSTRACT A Luminex-based direct immunoassay (dLIA) platform has been developed to replace the standardized pneumococcal enzyme-linked immunosorbent assay platform. The multiplex dLIA simultaneously measures the concentration of serum immunoglobulin G (IgG) antibodies specific for pneumococcal capsular polysaccharide (PnPS) serotypes 1, 3, 4, 5, 6A, 6B, 7F, 9V, 14, 18C, 19A, 19F, and 23F. The assay uses poly-l-lysine (PLL)-conjugated PnPS, chemically coupled to spectrally distinct Luminex microspheres. Assay validation experiments were performed using residual human serum samples obtained from 13-valent pneumococcal conjugate vaccine (13vPnC) clinical studies. Assay results are expressed as IgG antibody concentrations in micrograms per milliliter using the international reference serum, 007sp. The lower limit of quantitation (LLOQ) for all serotypes covered in the 13-plex dLIA fell within the range of 0.002 to 0.038 µg/ml serum IgG. The difference between the lower limit and upper limit of the assay range was >500-fold for all serotypes, and assay variability was <20% relative standard deviation (RSD) for all serotypes. IgG antibody measurements were shown to be serotype-specific (some cross-reactivity was observed only between the structurally related serotypes 6A and 6B as well as 19A and 19F), and no interference was observed between the serotypes when the assay was performed in the 13-plex format compared to the singleplex assays. The 13-plex dLIA platform developed by Pfizer Inc. generates up to 143 test results in a single 96-well plate and is a suitable replacement of the enzyme-linked immunosorbent assay (ELISA) platform for evaluating vaccine clinical trials. IMPORTANCE The pneumococcal enzyme-linked immunosorbent assay (ELISA) measures IgG antibodies in human serum, and it is an important assay that supports licensure of pneumococcal vaccines. The immune correlate of protection, 0.35 µg/ml of IgG antibodies, was determined by the ELISA method. Pfizer has developed a new Luminex-based assay platform to replace the ELISA. These papers describe the important work of (i) validating the Luminex-based assay and (ii) bridging the immune correlate of protection (0.35 µg/ml IgG) to equivalent values reported by the Luminex platform.

scholarly journals Antibody level of New Zealand children immunized with the triple vaccine DTP (diphtheria-tetanus-pertussis)

1988 ◽  
Vol 101 (2) ◽  
pp. 405-410 ◽  
Author(s):  
R. C. H Lau
Keyword(s):  
New Zealand ◽  
Immunosorbent Assay ◽  
Antibody Level ◽  
Herd Immunity ◽  
Enzyme Linked Immunosorbent Assay ◽  
Igg Antibody ◽  
Immunization Strategy ◽  
The Mean ◽  
Antibody Levels

SUMMARYEnzyme-linked immunosorbent assay (ELISA) tests were used to measure IgG antibody levels in 2638 New Zealand children who had been immunized with the triple vaccine DTP. The percentage of children immune to diphtheria decreased with age. The percentage of children immune to tetanus varied from 67.1 to 55.0%. The percentage of children with measurable antibody to pertussis increased with age. The mean percentages of children with measurable antibody or immunity to one or more DTP components were 34.2% (with 3 components), 34.4% (2 components), and 78.1% (1 component). It appears the immunization strategy for diphtheria and tetanus is satisfactory for herd immunity in New Zealand children. However, the current pertussis strategy may not be providing adequate immunity to 5-year-olds in this country.

scholarly journals Pneumococcal Type 22F Polysaccharide Absorption Improves the Specificity of a Pneumococcal-Polysaccharide Enzyme-Linked Immunosorbent Assay

2001 ◽  
Vol 8 (2) ◽  
pp. 266-272 ◽  
Author(s):  
Nelydia F. Concepcion ◽  
Carl E. Frasch
Keyword(s):  
Correlation Coefficient ◽  
Immunosorbent Assay ◽  
Pneumococcal Vaccination ◽  
Correlation Coefficients ◽  
Enzyme Linked Immunosorbent Assay ◽  
Igg Antibody ◽  
Functional Activities ◽  
Antibody Titers ◽  
The Common ◽  
Elisa Inhibition

ABSTRACT The specificity of the immune response to the 23-valent pneumococcal-polysaccharide (PS) vaccine in healthy adults and to a pneumococcal conjugate vaccine in infants was examined by measuring immunoglobulin G (IgG) antibody titers by enzyme-linked immunosorbent assay (ELISA) and the opsonophagocytosis assay. ELISA measures total antipneumococcal IgG titers including the titers of functional and nonfunctional antibodies, while the opsonophagocytosis assay measures only functional-antibody titers. Twenty-four pairs of pre- and post-pneumococcal vaccination sera from adults were evaluated (ELISA) for levels of IgG antibodies against serotypes 4, 6B, 9V, 14, 18C, 19F, and 23F. Twelve of the pairs were also examined (opsonophagocytosis assay) for their functional activities. The correlation coefficients between assay results for most types ranged from 0.75 to 0.90, but the correlation coefficient was only about 0.6 for serotypes 4 and 19F. The specificities of these antibodies were further examined by the use of competitive ELISA inhibition. A number of heterologous polysaccharides (types 11A, 12F, 15B, 22F, and 33A) were used as inhibitors. Most of the sera tested showed cross-reacting antibodies, in addition to those removed by pneumococcal C PS absorption. Our data suggest the presence of a common epitope that is found on most pneumococcal PS but that is not absorbed by purified C PS. Use of a heterologous pneumococcal PS (22F) to adsorb the antibodies to the common epitope increased the correlation between the IgG ELISA results and the opsonophagocytosis assay results. The correlation coefficient improve from 0.66 to 0.92 for type 4 and from 0.63 to 0.80 for type 19F. These common-epitope antibodies were largely absent in infants at 7 months of age, suggesting the carbohydrate nature of the epitope.

scholarly journals Immune complexes containing factor V in a patient with an acquired neutralizing antibody

Blood ◽  
1985 ◽  
Vol 65 (4) ◽  
pp. 810-818 ◽  
Author(s):  
HC Chiu ◽  
AK Rao ◽  
C Beckett ◽  
RW Colman
Keyword(s):  
Immunosorbent Assay ◽  
Immune Complexes ◽  
Neutralizing Antibody ◽  
Circulating Immune Complexes ◽  
Heat Inactivation ◽  
Enzyme Linked Immunosorbent Assay ◽  
Antibody Concentration ◽  
Factor V ◽  
Igg Antibody ◽  
Plasma Factor

Abstract An 82-year-old woman presented with extensive hematomas and melena associated with markedly decreased plasma factor V coagulant activity (FV:C). Using a competitive enzyme-linked immunosorbent assay developed in our laboratory, we made serial measurements of factor V antigen (FV:Ag) in plasma and found it to be normal or elevated. The patient's plasma was demonstrated to contain an IgG antibody that could neutralize FV:C in normal plasma. The antibody was of restricted heterogeneity (IgG1, IgG2,kappa). Circulating immune complexes containing antibody to factor V and FV:Ag were demonstrated directly in the plasma by immunoelectrophoresis with polyclonal monospecific antibody and with a monoclonal antibody using an enzyme-linked immunosorbent assay. Presence of neutralizing antibody could be demonstrated in vitro even at times when FV:C was within normal limits by heat inactivation of FV:C. Treatment with plasma and platelet transfusions as well as plasmapheresis induced definite but transient elevation of FV:C. Steroid therapy lowered the neutralizing antibody concentration and produced a rapid and persistent elevation of FV:C during two separate hospitalizations. This report describes a patient in whom levels of FV:Ag have been serially measured, and the presence of circulating immune complexes consisting of factor V and a neutralizing antibody have been directly demonstrated.

scholarly journals A Modified Enzyme-Linked Immunosorbent Assay for Measurement of Antibody Responses to Meningococcal C Polysaccharide That Correlate with Bactericidal Responses

1998 ◽  
Vol 5 (4) ◽  
pp. 479-485 ◽  
Author(s):  
Dan M. Granoff ◽  
Susan E. Maslanka ◽  
George M. Carlone ◽  
Brian D. Plikaytis ◽  
George F. Santos ◽  
...  
Keyword(s):  
Immunosorbent Assay ◽  
Geometric Mean ◽  
Correlation Coefficients ◽  
Antibody Responses ◽  
Enzyme Linked Immunosorbent Assay ◽  
High Avidity ◽  
Igg Antibody ◽  
Standard Assay ◽  
Bactericidal Antibody ◽  
Antibody Titers

ABSTRACT The standardized enzyme-linked immunosorbent assay (ELISA) for measurement of serum immunoglobulin G (IgG) antibody responses to meningococcal C polysaccharide has been modified to employ assay conditions that ensure specificity and favor detection primarily of high-avidity antibodies. The modified and standard assays were used to measure IgG antibody concentrations in sera of toddlers vaccinated with meningococcal polysaccharide vaccine or a meningococcal C conjugate vaccine. The results were compared to the respective complement-mediated bactericidal antibody titers. In sera obtained after one or two doses of vaccine, the correlation coefficients, r, for the results of the standard assay and bactericidal antibody titers were 0.45 and 0.29, compared to 0.85 and 0.87, respectively, for the modified assay. With the standard assay, there were no significant differences between the geometric mean antibody responses of the two vaccine groups. In contrast, with the modified assay, 5- to 20-fold higher postvaccination antibody concentrations were measured in the conjugate than in the polysaccharide group. Importantly, the results of the modified assay, but not the standard ELISA, paralleled the respective geometric mean bactericidal antibody titers. Thus, by employing conditions that favor detection of higher-avidity IgG antibody, the modified ELISA provides results that correlate closely with measurements of antibody functional activity that are thought to be important in protection against meningococcal disease.

scholarly journals Peptide-Based OspC Enzyme-Linked Immunosorbent Assay for Serodiagnosis of Lyme Borreliosis

1998 ◽  
Vol 36 (12) ◽  
pp. 3474-3479 ◽  
Author(s):  
Marianne J. Mathiesen ◽  
Michael Christiansen ◽  
Klaus Hansen ◽  
Arne Holm ◽  
Eva Åsbrink ◽  
...  
Keyword(s):  
Lyme Borreliosis ◽  
Immunosorbent Assay ◽  
Erythema Migrans ◽  
Immunoglobulin M ◽  
Enzyme Linked Immunosorbent Assay ◽  
Amino Acid Residues ◽  
Serum Samples ◽  
Igg Antibody ◽  
Acrodermatitis Chronica Atrophicans ◽  
Increased Sensitivity

Sera from 210 patients with Lyme borreliosis (LB) were studied by an enzyme-linked immunosorbent assay (ELISA) based on a synthetic peptide (pepC10) comprising the C-terminal 10-amino-acid residues of OspC of Borrelia burgdorferi. We found that 36.3 and 45.0% of the serum samples from patients with erythema migrans (EM) and neuroborreliosis (NB), respectively, displayed immunoglobulin M (IgM) anti-pepC10 reactivities, while these samples rarely (≤8%) displayed IgG antibody reactivities. Sera from patients with acrodermatitis chronica atrophicans did not contain anti-pepC10 antibodies. The diagnostic performance of this newly developed peptide ELISA was compared with those of an ELISA based on the full-length recombinant OspC protein (rOspC) and a commercially available ELISA based on theB. burgdorferi flagellum (Fla). The sensitivity of the IgM pepC10 ELISA was slightly lower (P < 0.04) than that of the rOspC ELISA for EM patients (36.3 versus 43.8%), while there was no difference for NB patients (45.0 versus 48.0%). However, the optical density values obtained by the pepC10 ELISA were generally higher than those obtained by the rOspC ELISA, leading to a significantly better quantitative discrimination between seropositive patients with NB and controls (P < 0.008). The specificity of the pepC10 ELISA was similar to those of the rOspC ELISA and the Fla ELISA for relevant controls including patients with syphilis and mononucleosis. Although the overall diagnostic sensitivity of the Fla ELISA was superior, 8.8 and 12.0% of the EM and NB patients, respectively, were antibody positive only by the pepC10 ELISA. Thus, use of a diagnostic test for LB based on the detection of IgM antibodies to pepC10 and Fla has increased sensitivity for the diagnosis of early LB.

scholarly journals Enzyme-Linked Immunosorbent Assay for Measurement of Cytomegalovirus Glycoprotein B Antibody in Serum

2010 ◽  
Vol 17 (5) ◽  
pp. 836-839 ◽  
Author(s):  
Daniel J. Hackett ◽  
Changpin Zhang ◽  
Carla Stefanescu ◽  
Robert F. Pass
Keyword(s):  
Immunosorbent Assay ◽  
Geometric Mean ◽  
Mean Value ◽  
Glycoprotein B ◽  
Enzyme Linked Immunosorbent Assay ◽  
Igg Antibody ◽  
Negative Results ◽  
Wide Range ◽  
The Mean ◽  
Antibody Levels

ABSTRACT Measurement of antibody to cytomegalovirus (CMV) glycoprotein B (gB) is valuable in the assessment of the antibody response to infection and to gB-containing vaccines. For this purpose, an enzyme-linked immunosorbent assay (ELISA) with a recombinant CMV gB molecule as the antigen was evaluated. Sera from 168 anti-CMV IgG-positive and 100 seronegative subjects were used to evaluate the anti-gB antibody assay. A cutoff optical density (OD) that would distinguish gB antibody-positive from -negative sera was established. Titers of antibody to gB determined by endpoint dilution were compared with those calculated using regression analysis. The run-to-run and interoperator reproducibilities of results were measured. The mean OD + 5 standard deviations from 50 anti-CMV IgG antibody-negative sera (0.2472) was used as the cutoff between anti-gB antibody-positive and -negative results. All sera from 100 anti-CMV IgG-seronegative subjects were negative for antibody to gB. All but 1 of 168 sera from seropositive subjects were positive for antibody to gB. Observed antibody levels based on titration to the endpoint were very similar to results calculated using linear regression. The run-to-run consistency of endpoints was excellent, with 38 runs from one operator and 48 runs from another all giving results within 1 dilution of the mean value for each of three anti-CMV IgG antibody-positive serum pools. The geometric mean titer of antibody to gB for 99 sera from seropositive blood donors was 1/10,937. This ELISA gives accurate and reproducible results for the relative quantity of anti-CMV gB IgG in serum over a wide range of antibody levels.

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