Functional Antibody-Dependent Enhancement as an Immune Assessment Platform: Development, Standardization, and Translational Interpretation in Flavivirus Research

  1. Meng Ling Moi

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Abstract

Functional antibody-dependent enhancement (ADE) represents a fundamental and context-dependent characteristic of antiviral antibody responses, reflecting the dual capacity of antibodies to mediate both the neutralization and Fc receptor-dependent enhancement of infection. In flavivirus research, this duality complicates the interpretation of conventional serological metrics and limits the reliability of single-parameter correlates of immunity, particularly in populations with complex exposure histories. Over the past decade, functional ADE assays have evolved from specialized mechanistic tools into integrated immune assessment platforms supporting translational immunology, vaccine evaluation, and population-level immune surveillance. These platforms incorporate Fcγ receptor-relevant target cell systems, standardized viral inputs, dilution series-based profiling, quantitative enhancement metrics, and structured quality control frameworks to enable reproducible, comparable, and context-aware functional measurements across cohorts and laboratories. A central concept emerging from these developments is that ADE reflects a dynamic functional immune state rather than an intrinsic property of antibodies or a direct indicator of pathological risk. Accordingly, functional ADE platforms support the contextual interpretation of antibody activity across physiologically relevant conditions, facilitating discrimination between transient functional enhancement and clinically meaningful immunological risk. By integrating functional ADE metrics with serological, cellular, and epidemiological data, these platforms provide a structured framework for interpreting immune profiles in vaccine evaluation, booster strategy design, and population-level risk stratification. This review synthesizes the development, standardization, and global dissemination of functional ADE platforms and discusses key principles governing biological relevance, analytical robustness, and inter-site transferability. Emerging directions integrating functional ADE profiling with systems immunology, immunogenomics, and computational modeling are highlighted as pathways toward predictive, decision-support-oriented frameworks. By positioning ADE platforms as immune assessment infrastructures rather than isolated assays, this review underscores their value for mechanistic inquiry, translational interpretation, and preparedness-oriented responses to emerging viral threats in the absence of definitive correlates of protection.

Article activity feed

  1. Version published to 10.3390/pathogens15050490
  2. PREreview

    This Zenodo record is a permanently preserved version of a PREreview. You can view the complete PREreview at https://prereview.org/reviews/18738093.

    Manuscript titled "Functional Antibody-Dependent Enhancement as an Immune Assessment Platform: Development, Standardization, and Translational Interpretation in Flavivirus Research," provides a comprehensive and timely synthesis of how Antibody-Dependent Enhancement (ADE) assays have evolved from specialized mechanistic tools into standardized, multi-site platforms for vaccine evaluation and population-level surveillance.

    The manuscript is well-structured, shifting the focus from viewing ADE as a binary "risk" to a dynamic "functional state" that can be quantitatively mapped to inform clinical and regulatory decisions.

    1. General Strengths

    • Conceptual Clarity: The paper excellently articulates the shift from "single-readout" experiments to "integrated assessment platforms." The distinction between ADE as a functional state versus an intrinsic antibody property is a critical conceptual framework for the field.

    • Timeliness: Given the ongoing challenges in developing safe and effective vaccines for Dengue and other flaviviruses, the focus on standardized immune assessment is highly relevant for both academic researchers and vaccine developers.

    • High-Quality Visuals: Figures 1 through 4 are exceptional. They effectively summarize complex timelines, modular architectures, terminology, and longitudinal immune trajectories, making the concepts accessible and reproducible.

    • Regulatory Relevance: Explicitly mentioning the WHO Expert Committee on Biological Standardization (ECBS) evaluations grounds the review in real-world application and policy.

    2. Content-Specific Comments and Suggestions

    Section 2: Conceptual Foundations

    • Cell System Comparison: In section 2.4, the author discusses various assay architectures. While the trade-offs between engineered cell lines (e.g., BHK-FcγRIIA) and primary cells are mentioned, a more explicit "pros and cons" table or a deeper discussion on when to choose one over the other based on the research question (e.g., high-throughput screening vs. deep mechanistic inquiry) would be a valuable addition for laboratories looking to adopt these platforms.

    • Viral Input Maturation: The mention of "maturation state (e.g., prM cleavage)" as a hidden confounder is excellent. Expanding slightly on how different cell lines used for virus production (e.g., C6/36 vs. Vero) affect this maturation and subsequently influence ADE readouts would further strengthen the standardization guidelines.

    Section 3: Applications across Research and Translational Context

    • Systems Immunology Examples: The review mentions the integration of ADE profiling with systems immunology and computational modeling (Fig. 4D). To provide even more depth, the author could briefly cite or describe 1-2 specific examples of how machine learning or predictive models have successfully utilized ADE platform data to stratify risk in clinical cohorts.

    • "Disease X" Preparedness: The inclusion of pandemic preparedness is a strong point. It might be worth explicitly mentioning how these standardized platforms could be rapidly adapted for non-flavivirus emerging pathogens (as hinted in the abbreviations/references regarding SARS-CoV-2 and Ebola).

    Section 4: Methods and Reporting Standards

    • Inter-laboratory Transfer Challenges: While reproducibility challenges are mentioned, Section 4.2 could benefit from a short "Common Pitfalls" paragraph regarding the actual process of protocol transfer between sites (e.g., differences in CO2 incubator calibration, serum heat-inactivation protocols, or plate-reader sensitivities).

    • Terminology Box (Figure 3): This is a standout feature. Standardizing terms like Emax and EAUC is vital for cross-study meta-analyses.

    3. Minor Technical/Formatting Points

    • Abbreviations: The list of abbreviations is comprehensive. Ensure that all abbreviations (like "SRIP" or "FFU") are defined at their first mention in the main text as well as in the list.

    • Figure 4 Legend: The legend is very detailed; however, in Figure 4C, the transition from "transient enhancement phase" to "protective dominance" is a core takeaway. Explicitly linking this to the "stoichiometric coverage" mentioned in the text would help tie the visual and textual data together more tightly.

    Overall Recommendation

    This is a high-quality review that serves as both a "state-of-the-field" summary and a practical guide for standardization. It is highly recommended for publication as it addresses a significant gap in the harmonization of functional immunoassays. The forward-looking integration of ADE platforms with multi-omic data (Figure 2, Module G) sets a clear and ambitious direction for future flavivirus research.

    Competing interests

    The author declares that they have no competing interests.

    Use of Artificial Intelligence (AI)

    The author declares that they did not use generative AI to come up with new ideas for their review.

  3. PREreview

    This Zenodo record is a permanently preserved version of a PREreview. You can view the complete PREreview at https://prereview.org/reviews/18645383.

    Summary

    This review article provides a timely and comprehensive synthesis of Antibody-Dependent Enhancement (ADE) in the context of flavivirus research. It successfully argues for a paradigm shift: moving from treating ADE as a binary "risk factor" to utilizing it as a standardized, multidimensional "immune assessment platform." The author effectively outlines the technical requirements for standardization (target cell selection, viral input, and quantitative metrics) and highlights the translational value of these platforms for vaccine development and population surveillance. The manuscript is well-structured, the figures are of high conceptual quality, and the emphasis on methodological governance is a significant contribution to the field.

    Major Strengths

    Emphasis on Standardization: The most valuable contribution of this review is the "Modular Architecture" (Figure 2) and the "Standardized Metric Framework" (Figure 3). The field has long suffered from inter-laboratory variability; by defining

    EmaxE_{max}Emax ,EAUCE_{AUC}EAUC

    , and reporting standards, this paper provides a roadmap for reproducibility.

    1. Conceptual Clarity: The author does an excellent job of reframing ADE not as an "intrinsic property" of an antibody, but as a "functional state" dependent on concentration and biological context.

    2. Visual Aids: The figures are exceptional. Figure 4, in particular, provides a very clear longitudinal view of how antibody profiles shift from enhancement-prone to neutralization-dominant after secondary infection.

    3. Forward-Looking Scope: The integration of "Systems Immunology" and "Predictive Modeling" (Section 3.3 and 4.4) ensures the review is relevant for next-generation vaccine design.

    4. AI Disclosure: Author has disclosed AI usage and its purpose in the article and ensure article is not a full reflection of the generative AI contents. Also instrumental for publication transparency.

    Areas for Improvement & Constructive Feedback

    1. Technical Nuance: FcγR Polymorphisms

    In Section 2.3, the author mentions that receptor polymorphisms (e.g., FcγRIIA) are key variables. Given that this review advocates for "Standardized Platforms," it would be beneficial to include a brief discussion or a recommendation on how platforms should handle common polymorphisms (like the H131R variant in FcγRIIa) in their standardized cell lines. Should labs use a specific variant as a "gold standard," or should they test a panel?

    2. Practical Implementation in LMICs

    Flaviviruses are primarily endemic in Low- and Middle-Income Countries (LMICs). While the paper discusses "inter-laboratory transfer," it would strengthen the review to include a brief paragraph on the feasibility and cost-effectiveness of these platforms. For example, comparing the resource requirements of live-virus plaque assays versus reporter virus systems or SRIPs in resource-limited settings.

    3. Specificity in "Vaccine Failure" Cases

    In Section 5, the author notes that ADE shouldn't be seen as an "intrinsic marker of vaccine failure." The review would be more impactful if it briefly cited the specific lessons learned from the Dengvaxia (CYD-TDV) experience or other recent trials where the lack of these standardized ADE metrics may have hindered early risk stratification.

    4. Terminology: Intrinsic vs. Extrinsic ADE

    The paper mentions "extrinsic" (entry-level) and "intrinsic" (post-entry signaling) ADE (Section 2.3). It would be helpful to clarify if the proposed "Standardized Platform" is intended to measure both, or if current high-throughput platforms (like reporter viruses) are primarily limited to measuring extrinsic ADE.

    Minor Points and Typographical Corrections

    • OCR/Typo Check: There is a recurring typo throughout the document (likely from the drafting process): the word "settings" is frequently misspelled as "seings" (e.g., Page 3, 5, 9, 13, 14, 15).

    • Figure 1 Legend: Ensure the mention of "Moi et al., 2010–2012" in the legend is explicitly linked to the references provided in the bibliography to help readers trace the origin of the first transferable platforms.

    • Abbreviations: The abbreviation list is comprehensive, but ensure "SRIP" (Single-Round Infectious Particle) is used consistently, as some sections refer to "pseudotypes" interchangeably.

    Final Recommendation

    This is a high-quality review that will likely become a standard reference for laboratories establishing ADE assays. Once the minor typographical errors (e.g., "seings") are corrected and the technical points regarding polymorphism/LMIC implementation are considered, this manuscript will be an excellent addition to the literature.

    Competing interests

    The author declares that they have no competing interests.

    Use of Artificial Intelligence (AI)

    The author declares that they did not use generative AI to come up with new ideas for their review.

  4. Version published to 10.20944/preprints202602.0709.v1