Validation and long term performance characteristics of a quantitative enzyme linked immunosorbent assay (ELISA) for human anti-PA IgG

Semenova, Vera; Schiffer, Jarad; Steward‐Clark, Evelene; Soroka, Stephen; Schmidt, Daniel S.; Brawner, M.M.; Lyde, Freda C.; Thompson, R. A.; Brown, Nekeidra; Foster, L. E.; Fox, Sarah P.; Patel, Nishi; Freeman, Alison; Quinn, Conrad P.

doi:10.1016/j.jim.2011.12.002

Cited by 49 publications

(52 citation statements)

References 40 publications

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“…The quantitative anti-PA IgG enzyme-linked immunosorbent assay (ELISA) was performed according to the method of Semenova et al (15). The assay empirical lower limits of detection (LOD) and quantification (LLOQ) were 1.7 g/ml and 3.7 g/ml of anti-PA IgG, respectively (15).…”

Section: Methodsmentioning

confidence: 99%

Humoral and Cell-Mediated Immune Responses to Alternate Booster Schedules of Anthrax Vaccine Adsorbed in Humans

Quinn

Sabourin

Schiffer

et al. 2016

Clin Vaccine Immunol

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A nthrax vaccine adsorbed (AVA; BioThrax; Emergent Bio Solutions Inc., Lansing, MI) is the only Food and Drug Administration (FDA)-approved vaccine in the United States for prevention of anthrax in humans. The primary immunogen in AVA is anthrax toxin protective antigen (PA). Serum anti-PA antibody levels are accurate immune correlates of protection in nonhuman primate (NHP) models of inhalation anthrax and for predicted probability of survival in humans (1-3). There is a significant lack of data in humans regarding the onset, duration, quantitative analysis, and functional activity of humoral antibody and cell-mediated immunity (CMI) responses following priming and boosting with AVA.In 2012, the preexposure schedule for AVA was approved as a priming series of three 0.5-ml intramuscular (IM) injections at 0, 1, and 6 months (3-IM) with subsequent boosters at 12 and 18 months and annually thereafter for those at continued risk of infection (http://www.fda.gov/BiologicsBloodVaccines/Vaccines /ApprovedProducts/ucm304758.htm; http://www.fda.gov /downloads/BiologicsBloodVaccines/BloodBloodProducts /ApprovedProducts/LicensedProductsBLAs/UCM074923 .pdf). In 2013, AVA received market approval in the European Union (EU) using a 3-IM priming series and 3-yearly booster schedule (http://emergentbiosolutions.com/sites/default/files /BioThrax_Germany.pdf).These recent changes in the FDA-approved priming schedule and route of administration for AVA and EU approval of an alternate schedule warranted detailed characterization of their immunological impact. Serological noninferiority analyses for peak anti-PA IgG and lethal toxin neutralization activity (TNA) in response to the 3-IM priming schedule and alternative booster schedules were reported previously, and the safety profile of AVA administered IM in humans was confirmed to be similar to that for other alum-containing vaccines (4-6). Less frequent AVA injection doses resulted in a reduction in some injection site adverse events (AEs), and IM administration resulted in reduced frequency, duration, and severity of AEs (5-11). The potential for increasing the intervals between booster doses requires an assessment of sustained antibody functional activity, CMI, and the ability to develop rapid protective anamnestic responses (5,6,12).In a rhesus macaque model of inhalation anthrax, the AVA

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Section: Methodsmentioning

confidence: 99%

Humoral and Cell-Mediated Immune Responses to Alternate Booster Schedules of Anthrax Vaccine Adsorbed in Humans

Quinn

Sabourin

Schiffer

et al. 2016

Clin Vaccine Immunol

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“…Compared with the single-correlate model with last anti-PA IgG only, the predictive accuracy was slightly improved but not statistically significantly different using the dual-correlate models containing last anti-PA IgG or PCLR models containing all five variables or the Par_elastic_Elasticnet variable set except SI at month 6, and it was slightly decreased but not statistically significantly different using all other dual-correlate models. Given the lower technical complexity, higher sample stability, and higher throughput of an enzyme-linked immunosorbent assay (ELISA) than those of a lymphocyte proliferation assay, together with the ability to accurately calibrate ELISA standards and quantify the IgG analyte for each species (15,37), these data confirm that last anti-PA IgG provides an appropriate correlate of protection for cross-species survival predictions (4).…”

Section: Discussionmentioning

confidence: 84%

Comprehensive Analysis and Selection of Anthrax Vaccine Adsorbed Immune Correlates of Protection in Rhesus Macaques

Chen

Schiffer

Dalton

et al. 2014

Clin. Vaccine Immunol.

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T o date, there has not been a systematic evaluation of the relationship between anthrax vaccine-stimulated humoral and cell-mediated immune responses, their relative contributions to protection, or their comparative importance when used singly or in combination to predict the probability of survival in animal models or in humans.Anthrax toxin protective antigen (PA) is the primary immunogen in licensed anthrax vaccines in the United States and the European Union, as well as in many of the second-generation anthrax vaccines in current development (1). Consequently, the quantitative analysis of anti-PA IgG antibody levels and lethal toxin neutralization activity (TNA) in serum are generally accepted as immunological correlates of protection (COP) for vaccine efficacy in animal models (2). Anti-PA IgG levels and TNA are also considered pivotal for cross-species predictions of anthrax vaccine efficacy in humans, for whom clinical efficacy studies are either impractical or ethically infeasible (3, 4) (http://www.fda .gov/AdvisoryCommittees/CommitteesMeetingMaterials/Blood VaccinesandOtherBiologics/VaccinesandRelatedBiologicalProducts AdvisoryCommittee/ucm239733.htm). Anti-PA IgG and TNA levels, however, are but one part of the spectrum of humoral and cell-mediated immune responses that may contribute to protection. The COP for anthrax may differ depending on vaccine formulations, schedules, and routes of administration (5-10).The U.S.-licensed anthrax vaccine adsorbed (AVA) (BioThrax) was approved in 1970 for the prevention of anthrax in humans (11)(12)(13)(14). The original regimen for AVA was a subcutaneous (s.c.) six-dose primary schedule at 0, 0.5, 1, 6, 12, and 18 months, with subsequent annual boosters. In May 2012, the U.S. Food and Drug Administration (FDA) approved the AVA regimen as an intramuscular (i.m.) three-dose priming schedule at 0, 1, and 6 months, with boosters at 12 and 18 months and annually thereafter (http://www .fda.gov/BiologicsBloodVaccines/Vaccines/ApprovedProducts /ucm304758.htm). These recent changes in the schedule and administration route were based on data from the Centers for Disease Control and Prevention Anthrax Vaccine Research Program (AVRP) (12, 13). The goals of the AVRP were to improve the AVA safety profile and ensure efficacy while minimizing the number of doses required. The study objectives included determining immunological correlates of protection, documenting vaccine efficacy, and optimizing the vaccination schedule and route of administration (14). Due to the low prevalence of inhalation anthrax and the ethical concerns of conducting an efficacy trial in humans, vaccine efficacy and duration of protection were evaluated in rhesus macaques (Macaca mulatta) (15).The AVRP nonhuman primate (NHP) study used the 0-, 1-, and 6-month intramuscular priming series (3-i.m.) with a full human dose or saline dilutions of AVA to modulate the immune response. The NHP were challenged with high-dose (median, 504ϫ the 50% lethal dose [LD 50 ]) aerosolized Bacillus anthracis spores at m...

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“…Sera from the CDC Anthrax Vaccine Research Program (AVRP) clinical trial participants and clinical trial site IRB approvals were obtained as described previously [1]. The preparation of the standard AVR801, positive quality controls (QCs) (AVR1749, AVR1750 and AVR1751) and negative QC (AVR811) used in the study have been described previously [2,8]. …”

Section: Methodsmentioning

confidence: 99%

“…The method of quantitative anti-PA IgG ELISA has been described previously [2]. The main difference in the current assay is in the plate format: the reference standard is run in duplicate instead of in triplicate and test samples are run in a single well at one dilution instead of in duplicate and at 8 serial dilutions.…”

Section: Methodsmentioning

confidence: 99%

“…A set of five acceptance criteria for assay performance in the high throughput screening format were similar to the acceptance criteria for the CDC validated anti-PA IgG ELISA [2,9]. These five assay acceptance criteria were: 1) the mean Optical Density (OD) value of the negative control was required to be less than 0.200 OD units; 2) the standard reference serum was required to have a weighted coefficient of determination (r 2 ) value of ≥0.990 to the 4-Parameter Logistic (4-PL) model; 3) the mean anti-PA IgG concentration for each of three positive quality control sera were required to have coefficients of variation (CV) <20%; 4) at least 2 of 3 positive control sera were required to have anti-PA IgG concentrations within 2 standard deviations (SD) of their expected values and 5) no positive control sera anti-PA IgG concentrations were allowed to be >3SD from the expected value.…”

Section: Methodsmentioning

confidence: 99%

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Validation of high throughput screening of human sera for detection of anti-PA IgG by Enzyme-Linked Immunosorbent Assay (ELISA) as an emergency response to an anthrax incident

et al. 2017

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To improve surge testing capability for a response to a release of Bacillus anthracis, the CDC anti-Protective Antigen (PA) IgG Enzyme-Linked Immunosorbent Assay (ELISA) was re-designed into a high throughput screening format. The following assay performance parameters were evaluated: goodness of fit (measured as the mean reference standard r2), accuracy (measured as percent error), precision (measured as coefficient of variance (CV)), lower limit of detection (LLOD), lower limit of quantification (LLOQ), dilutional linearity, diagnostic sensitivity (DSN) and diagnostic specificity (DSP). The paired sets of data for each sample were evaluated by Concordance Correlation Coefficient (CCC) analysis. The goodness of fit was 0.999; percent error between the expected and observed concentration for each sample ranged from −4.6% to 14.4%. The coefficient of variance ranged from 9.0% to 21.2%. The assay LLOQ was 2.6 μg/mL. The regression analysis results for dilutional linearity data were r2 = 0.952, slope = 1.02 and intercept = −0.03. CCC between assays was 0.974 for the median concentration of serum samples. The accuracy and precision components of CCC were 0.997 and 0.977, respectively. This high throughput screening assay is precise, accurate, sensitive and specific. Anti-PA IgG concentrations determined using two different assays proved high levels of agreement. The method will improve surge testing capability 18-fold from 4 to 72 sera per assay plate.

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Validation and long term performance characteristics of a quantitative enzyme linked immunosorbent assay (ELISA) for human anti-PA IgG

Cited by 49 publications

References 40 publications

Humoral and Cell-Mediated Immune Responses to Alternate Booster Schedules of Anthrax Vaccine Adsorbed in Humans

Humoral and Cell-Mediated Immune Responses to Alternate Booster Schedules of Anthrax Vaccine Adsorbed in Humans

Comprehensive Analysis and Selection of Anthrax Vaccine Adsorbed Immune Correlates of Protection in Rhesus Macaques

Validation of high throughput screening of human sera for detection of anti-PA IgG by Enzyme-Linked Immunosorbent Assay (ELISA) as an emergency response to an anthrax incident

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