Challenges of Immunogenicity Assays For Vaccines

Kostense, Stefan; Hendriks, Jenny

doi:10.4155/bio.11.327

Cited by 11 publications

(13 citation statements)

References 26 publications

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“…Use of prevaccination RVNA values and serologic responses 3 to 7 weeks after vaccination to infer the prior vaccine history was potentially misleading because vaccinated horses may have had RVNA values that were lower than the LOD of the assay used, and unvaccinated horses may have had cross-reactive antibodies or other nonspecific inhibitors of virus that can mimic specific antibody in laboratory testing. [37][38][39][40] In addition, interpretation of serologic data to determine grouping may have introduced some degree of bias.…”

Section: Equinementioning

confidence: 99%

Duration of serum antibody response to rabies vaccination in horses

Harvey¹,

Watson²,

Brault³

et al. 2016

javma

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OBJECTIVETo investigate the impact of age and inferred prior vaccination history on the persistence of vaccine-induced antibody against rabies in horses. DESIGN Serologic response evaluation.ANIMALS 48 horses with an undocumented vaccination history. PROCEDURESHorses were vaccinated against rabies once. Blood samples were collected prior to vaccination, 3 to 7 weeks after vaccination, and at 6-month intervals for 2 to 3 years. Serum rabies virus-neutralizing antibody (RVNA) values were measured. An RVNA value of ≥ 0.5 U/mL was used to define a predicted protective immune response on the basis of World Health Organization recommendations for humans. Values were compared between horses < 20 and ≥ 20 years of age and between horses inferred to have been previously vaccinated and those inferred to be immunologically naïve. RESULTSA protective RVNA value (≥ 0.5 U/mL) was maintained for 2 to 3 years in horses inferred to have been previously vaccinated on the basis of prevaccination RVNA values. No significant difference was evident in response to rabies vaccination or duration of protective RVNA values between horses < 20 and ≥ 20 years of age. Seven horses were poor responders to vaccination. Significant differences were identified between horses inferred to have been previously vaccinated and horses inferred to be naïve prior to the study. CONCLUSIONS AND CLINICAL RELEVANCEA rabies vaccination interval > 1 year may be appropriate for previously vaccinated horses but not for horses vaccinated only once. Additional research is required to confirm this finding and characterize the optimal primary dose series for rabies vaccination. (J Am Vet Med Asssoc 2016;249:xxx-xxx) revaccination is currently recommended by vaccine manufacturers and in the vaccination guidelines of the AAEP. 3 Research in several animal species indicates that the primary correlate of protection against rabies is the presence of neutralizing antibody in serum. 4 The humoral immune response to rabies vaccination can be evaluated with the RFFIT or fluorescent antibody virus neutralization test, both of which are used for in vitro measurement of RVNA concentration in serum samples. The RFFIT is currently the gold standard and reference technique for most laboratories. [5][6][7] An RVNA titer of ≥ 0.5 U/mL is globally recognized as the threshold of seroconversion for humans. 7 Values reported in this manner (U/mL) are titers expressed as standard units. This value of 0.5 U/mL, when obtained via RFFIT or fluorescent antibody virus neutralization, is also recognized by regulatory authorities in most rabies-free areas as proof of adequate response to vaccination for importation of cats and dogs. 5 No general consensus currently exists regarding the RVNA titer needed to confer protection

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Section: Equinementioning

confidence: 99%

Duration of serum antibody response to rabies vaccination in horses

Harvey¹,

Watson²,

Brault³

et al. 2016

javma

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“…Critical decisions required to select antigens, adjuvants, formulations, number of doses, and the vaccination schedule are often dependent on immunogenicity assessments conducted in the early stages of clinical development. Assays are typically designed to measure the immune response following natural infection or vaccination (1). Flow cytometry-based intracellular cytokine staining (ICS) and enzyme-linked immunospot (ELISPOT) assays are often used for immune monitoring of antigen-specific T cell responses, which is important to the understanding of viral infections and the immune response following vaccination.…”

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confidence: 99%

Enzyme-Linked Immunospot Assay for Detection of Human Respiratory Syncytial Virus F Protein-Specific Gamma Interferon-Producing T Cells

Patton¹,

Aslam²,

Lin³

et al. 2014

Clin. Vaccine Immunol.

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Respiratory syncytial virus (RSV) causes significant disease in elderly adults, and we have previously reported that individuals 65 years of age and older have reduced RSV F protein-specific gamma interferon (IFN-␥)-producing T cells compared to healthy younger adults. To measure RSV F-specific memory T cell responses in the elderly following infection or vaccination, we optimized and qualified an IFN-␥ enzyme-linked immunospot (ELISPOT) assay. Since peripheral blood mononuclear cells (PBMC) from the elderly could be more fragile, we established optimal cryopreservation techniques and minimal viability acceptance criteria. The number of cells per well, types and concentrations of stimulation antigens, and incubation times were evaluated to maximize assay sensitivity and precision. The optimized assay uses 300,000 cells/well, 2 g/ml of an RSV F peptide pool (RSV Fpp), and incubation for 22 ؎ 2 h in serum-free CTL-Test medium. The assay was qualified by 3 analysts using 3 RSV F-responding donor PBMC samples (high, medium, and low responders) tested on 5 different assay days. The assay sensitivity or limit of detection (LOD) was determined to be 21 spot-forming cells (SFC) per 10 6 PBMC, and the lower limit of quantitation (LLOQ) was estimated to be 63 SFC/10 6 PBMC. The intra-and interassay percent coefficients of variation (CV) were <10.5% and <31%, respectively. The results of the qualification study demonstrate that a robust, precise, and sensitive IFN-␥ ELISPOT assay has been developed that is fit for measuring RSV F-specific IFN-␥ T cell responses in subjects enrolled in a vaccine clinical trial or in epidemiology studies.

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“…Immunogenicity testing requires that the targeted cut-off be robustly representative of, as a corollate, the level of protection, not the limit of detection (LOD) [ 18 ]. During the advent of modern cell culture rabies vaccines, the RVNA level of 0.5 IU/mL was determined to be a marker of adequate rabies immunization at 4 weeks after completion of the vaccination series, subsequently it has been interpreted to be proof of protection by some.…”

Section: Defining the Purpose Of Testing/context Of Interpretationmentioning

confidence: 99%

Challenges of Rabies Serology: Defining Context of Interpretation

Moore

2021

Viruses

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The case fatality rate of rabies, nearly 100%, is one of the most unique characteristic of this ancient virus infection. The crucial role rabies virus neutralizing antibody plays in protection is both well established and explanation of why rabies serology is important. Various laboratory methods can and have been used but serum neutralization methods have long been the gold standard due to the ability to measure function (neutralization), however these methods can be difficult to perform for several reasons. Assays such as enzyme linked absorbance assays (ELISA), indirect fluorescence antibody (IFA) and more recently lateral flow methods are in use. Interpretation of results can be problematic, not only between methods but also due to modifications of the same method that can lead to misinterpretations. A common assumption in review of laboratory test results is that different methods for the same component produce comparable results under all conditions or circumstances. Assumptions and misinterpretations provide the potential for detrimental decisions, ranging from regulatory to clinically related, and most importantly what ‘level’ is protective. Review of the common challenges in performance and interpretation of rabies serology and specific examples illuminate critical issues to consider when reviewing and applying results of rabies serological testing.

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Challenges of Immunogenicity Assays For Vaccines

Cited by 11 publications

References 26 publications

Duration of serum antibody response to rabies vaccination in horses

Duration of serum antibody response to rabies vaccination in horses

Enzyme-Linked Immunospot Assay for Detection of Human Respiratory Syncytial Virus F Protein-Specific Gamma Interferon-Producing T Cells

Challenges of Rabies Serology: Defining Context of Interpretation

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