Anti-RSV F Protein (Nirsevimab) [Clone MEDI8897]

Anti-RSV F Protein (Nirsevimab) [Clone MEDI8897]

Product No.: R210

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Product No.R210
Clone
MEDI8897
Target
Respiratory Syncytial Virus
Product Type
Biosimilar Recombinant Human Monoclonal Antibody
Alternate Names
Human respiratory syncytial virus (hRSV), Respiratory syncytial virus (RSV)
Isotype
Human IgG1κ
Applications
ELISA
,
FA

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Antibody Details

Product Details

Reactive Species
Human
Host Species
Human
Expression Host
HEK-293 Cells
FC Effector Activity
Active
Immunogen
Prefusion RSV F protein
Product Concentration
≥ 5.0 mg/ml
Endotoxin Level
< 1.0 EU/mg as determined by the LAL method
Purity
≥95% by SDS Page
≥95% monomer by analytical SEC
Formulation
This biosimilar antibody is aseptically packaged and formulated in 0.01 M phosphate buffered saline (150 mM NaCl) PBS pH 7.2 - 7.4 with no carrier protein, potassium, calcium or preservatives added. Due to inherent biochemical properties of antibodies, certain products may be prone to precipitation over time. Precipitation may be removed by aseptic centrifugation and/or filtration.
State of Matter
Liquid
Product Preparation
Recombinant biosimilar antibodies are manufactured in an animal free facility using only in vitro protein free cell culture techniques and are purified by a multi-step process including the use of protein A or G to assure extremely low levels of endotoxins, leachable protein A or aggregates.
Storage and Handling
Functional grade preclinical antibodies may be stored sterile as received at 2-8°C for up to one month. For longer term storage, aseptically aliquot in working volumes without diluting and store at ≤ -70°C. Avoid Repeated Freeze Thaw Cycles.
Regulatory Status
Research Use Only (RUO). Non-Therapeutic.
Country of Origin
USA
Shipping
2-8°C Wet Ice
Additional Applications Reported In Literature ?
FA,
ELISA
Each investigator should determine their own optimal working dilution for specific applications. See directions on lot specific datasheets, as information may periodically change.

Description

Description

Specificity
This non-therapeutic biosimilar antibody uses the same variable region sequence as the therapeutic antibody Nirsevimab. Nirsevimab binds the F1 and F2 subunits of the prefusion RSV F protein at a highly conserved epitope in antigenic site Ø.
Background
Respiratory syncytial virus (RSV) is a major cause of acute lower respiratory tract infection and hospitalization in infants1. RSV F protein is a type I integral membrane protein essential for viral membrane fusion that is highly conserved among isolates of RSV A and B subgroups2. F protein has been investigated as a target for neutralizing antibodies, small molecular antiviral drug development, as a vaccine antigen, and as an antibody target for passive prophylaxis.

F protein is synthesized as an inactive, palmitoylated precursor (F0) and is decorated with N-linked glycans2. Three F0 monomers form a trimer and become activated by a furin-like host protease as they pass through the Golgi. The protease cleaves twice, generating three polypeptides: F2 and F1, which are covalently linked, and pep27, an intervening peptide that dissociates after cleavage. When functional F protein trimer in the virion membrane is triggered, it undergoes a major conformational change from a prefusion to postfusion form. Approximately 25% of isolate specific variability for F protein is found within an antigenic site at the apex of the prefusion trimer (antigenic site Ø), composed of an α-helix from F1 (aa 196–210) and a strand from F2 (aa 62–69).

Nirsevimab is a long-acting, neutralizing recombinant human monoclonal antibody that binds the F1 and F2 subunits of F protein at a highly conserved epitope in antigenic site Ø and locks the RSV F protein in the prefusion conformation, blocking viral entry into the host cell1, 3, 4. In vitro, nirsevimab binds to immobilized human FcγRs (FcγRI, FcγRIIA, FcγRIIB and FcγRIII)3. Protection from infection is thought to be dependent on neutralization activity rather than Fc-mediated effector function based on data from a cotton rat model of RSV infection3. Nirsevimab has been modified with a triple amino acid substitution (YTE) in the Fc region to extend the serum half-life3. Nirsevimab originates from the D25 antibody developed by AIMM Therapeutics and was jointly developed and commercialized by AstraZeneca and Sanofi for the prevention of RSV infection in neonates and infants.
Antigen Distribution
F protein is found in RSV virion membranes in either an inactive prefusion conformation or an active postfusion conformation.
Ligand/Receptor
site A of the RSV-F glycoprotein
NCBI Gene Bank ID
UniProt.org
Research Area
Biosimilars
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Immunology
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Infectious Disease
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Seasonal and Respiratory Infections
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Viral
.
IVD Raw Material

Leinco Antibody Advisor

Powered by AI: AI is experimental and still learning how to provide the best assistance. It may occasionally generate incorrect or incomplete responses. Please do not rely solely on its recommendations when making purchasing decisions or designing experiments.

To use research-grade Nirsevimab biosimilars as calibration standards or reference controls in a pharmacokinetic (PK) bridging ELISA for measuring drug concentration in serum samples, several steps and considerations are necessary:

1. ELISA Principle

Nirsevimab ELISAs typically employ a quantitative competitive enzyme immunoassay technique. This involves pre-coating a microplate with a relevant antigen (e.g., recombinant human respiratory syncytial virus A fusion glycoprotein F0) and using HRP-labeled antibodies to competitively bind with the analyte (Nirsevimab) in the sample.

2. Calibration and Reference Standards

  • Preparation of Standards: To establish calibration curves, known concentrations of Nirsevimab biosimilars are prepared in serum. These standards will serve as reference points for quantifying unknown samples.
  • Analytical Standard Selection: A single NIRSEvimab biosimilar is often selected as the analytical standard for both biosimilar and reference products. This approach ensures that the same standard is used for calibration across different regions and products, reducing variability.

3. Assay Validation

  • Precision and Accuracy: Validate the assay by assessing precision and accuracy using multiple sets of standards and controls. This ensures that the assay can reliably measure Nirsevimab concentrations in serum.
  • Bioanalytical Comparability: Establish that the biosimilar and reference products are bioanalytically equivalent within the assay. This involves statistical analysis to confirm that the assay can accurately measure both products with similar precision and accuracy.

4. PK Bridging ELISA Implementation

  • Quantification: Use the validated ELISA to quantify Nirsevimab concentrations in serum samples by comparing sample absorbances to the calibration curve generated from the standards.
  • Data Analysis: Analyze the drug concentration data to determine pharmacokinetic parameters such as half-life, maximum concentration (Cmax), and area under the curve (AUC), which are crucial for understanding drug exposure and efficacy.

By following these steps, research-grade Nirsevimab biosimilars can effectively serve as calibration standards and reference controls in PK bridging ELISAs, ensuring accurate measurement of drug concentrations in serum samples.

Here is a summary of the key points in the following table:

ComponentDescriptionafort
ELISA PrincipleQuantitative competitive enzyme immunoassay
Calibration StandardsKnown concentrations of Nirsevimab biosimilars in serum
Analytical StandardSingle biosimilar used across different products
Assay ValidationPrecision, accuracy, and bioanalytical comparability
PK Bridging ELISAQuantification of Nirsevimab in serum samples using validated ELISA

This approach supports the development and comparison of biosimilar drugs by ensuring consistent and reliable measurement of drug concentrations.

Based on the available search results, there is no direct evidence that a research-grade anti-Respiratory Syncytial Virus (RSV) antibody has been administered in vivo to study tumor growth inhibition or to characterize tumor-infiltrating lymphocytes (TILs) in either syngeneic or humanized mouse tumor models.

Examination of Research Models

Syngeneic Models
Syngeneic tumor models in mice (e.g., RENCA, B16F10, CT26) are widely used to study the activity of immunotherapies, including checkpoint inhibitors and other immune-modulating agents. These models are valuable for profiling TILs and understanding tumor-immune interactions, as each model exhibits a unique immune microenvironment and response to therapy. However, there is no mention in the current literature of these models being used to test anti-RSV antibodies for tumor growth inhibition or TIL characterization.

Humanized and Xenograft Models
The primary in vivo model referenced for RSV and cancer research is the human prostate tumor xenograft model in nude mice, where RSV itself (not an antibody) is administered intratumorally or intraperitoneally to induce tumor regression via oncolysis. This study demonstrated that RSV selectively infects and kills cancer cells, leading to tumor regression, and characterized apoptosis pathways in the tumor, but did not involve administration of an anti-RSV antibody or analysis of TILs in the context of antibody therapy.

Antibody-Related RSV Research
There is research on antibodies that inhibit RSV entry by targeting the viral F protein, but these studies focus on viral infection mechanisms (e.g., blocking virus–cell fusion) rather than any antitumor effects or immune profiling in tumor models. Similarly, computational studies predict escape mutations in the RSV F protein that would allow the virus to evade antibody neutralization, but these are not linked to cancer models.

Summary Table

Model TypeRSV AdministrationAnti-RSV Antibody TestedTIL CharacterizationReference
Syngeneic (mice)NoNoYes (general)
Human xenograft (mice)Yes (RSV virus)NoNo
Humanized (mice)Not describedNoNot described

Conclusion

No primary syngeneic or humanized tumor models have been reported in which a research-grade anti-RSV antibody is administered to study tumor growth inhibition or to profile TILs. The existing body of work focuses either on the direct oncolytic effect of the RSV virus in xenografts or on the general utility of syngeneic models for immunotherapy and TIL profiling without reference to RSV or anti-RSV antibodies. Studies on anti-RSV antibodies are confined to virology and do not extend to cancer models.

Based on the available information, there appears to be a fundamental misunderstanding in this query. Nirsevimab is not used in conjunction with checkpoint inhibitors because it serves an entirely different therapeutic purpose.

Understanding Nirsevimab's Actual Function

Nirsevimab is a neutralizing antibody specifically designed to prevent respiratory syncytial virus (RSV) infections. It works by binding to the RSV F protein and neutralizing the virus, with demonstrated efficacy against both RSV-A and RSV-B subgroups. The biosimilar version available for research uses the same variable regions as the therapeutic antibody, making it suitable for studying RSV prevention mechanisms.

Checkpoint Inhibitors in Cancer Research

Checkpoint inhibitors, on the other hand, are cancer immunotherapy agents that work by blocking inhibitory signals in the immune system. The research focuses on combinations such as:

Anti-PD-1/PD-L1 and Anti-CTLA-4 Combinations: These target different mechanisms, with anti-CTLA-4 acting in lymph nodes to restore T cell activation, while anti-PD-1 acts at tumor sites to prevent T cell neutralization. The combination of nivolumab (anti-PD-1) and ipilimumab (anti-CTLA-4) has shown efficacy in melanoma, particularly in PD-L1-negative tumors.

Anti-LAG-3 Combinations: LAG3 inhibitors like relatlimab are combined with nivolumab (anti-PD-1) to achieve synergistic antitumor immunity. This combination has shown improved progression-free survival in metastatic melanoma with a more favorable safety profile compared to anti-PD-1 + anti-CTLA-4 combinations.

The Disconnect

The fundamental issue with the query is that nirsevimab biosimilars are not used in cancer immunotherapy research. Nirsevimab is an antiviral antibody for RSV prevention, while checkpoint inhibitors are cancer immunotherapy agents. These represent completely separate therapeutic domains with different mechanisms, targets, and applications.

Researchers studying synergistic effects in immune-oncology models focus on combinations of various checkpoint inhibitors (anti-PD-1, anti-CTLA-4, anti-LAG-3, anti-TIM-3, anti-TIGIT) rather than incorporating antiviral antibodies like nirsevimab into their experimental designs.

Nirsevimab biosimilars can be utilized as both capture and detection reagents in bridging ADA ELISA assays to monitor patient immune responses against this RSV therapeutic monoclonal antibody. The implementation follows established bridging ELISA principles adapted for this specific long-acting anti-RSV antibody.

Bridging ELISA Design for Nirsevimab

In a bridging ADA ELISA for nirsevimab, the biosimilar serves dual roles in the assay architecture. The capture phase involves coating streptavidin-coated microtiter plates with biotinylated nirsevimab biosimilar, which immobilizes the drug on the solid phase. Patient serum samples containing potential anti-nirsevimab antibodies are then added, allowing any ADAs present to bind to the immobilized drug.

The detection phase utilizes a labeled version of the nirsevimab biosimilar - typically conjugated with horseradish peroxidase (HRP) or biotin - which binds to the captured ADAs if they are bivalent. This creates a "bridge" formation where the ADA simultaneously binds both the capture reagent (immobilized nirsevimab) and the detection reagent (labeled nirsevimab), hence the term "bridging ELISA."

Specific Considerations for Nirsevimab

Given that nirsevimab is a recombinant human IgG1κ monoclonal antibody with YTE modifications that extend its serum half-life, several unique factors influence the assay design. The extended half-life characteristic means that circulating drug levels may persist longer in patients, potentially interfering with ADA detection. This necessitates careful optimization of assay conditions and may require acid dissociation pretreatment to separate drug-bound ADAs from free drug.

The high binding affinity of nirsevimab to RSV F protein (KD values of 0.12 nM and 1.22 nM for RSV subtypes A and B respectively) suggests that the biosimilar used in the assay should maintain similar binding characteristics to ensure accurate representation of the therapeutic's immunogenic potential.

Technical Implementation

The assay typically employs high-quality blocking solutions to minimize matrix interferences from human serum components, which is particularly important given the complexity of the serum matrix and potential presence of soluble RSV antigens or residual therapeutic drug. The biotinylation of the nirsevimab biosimilar for capture must be optimized to maintain the antibody's structural integrity while providing sufficient binding capacity.

For detection, the labeled nirsevimab biosimilar concentration must be carefully titrated to achieve optimal signal-to-noise ratios while avoiding saturation effects. The use of chromogenic substrates like TMB (3,3',5,5'-tetramethylbenzidine) with HRP-labeled detection reagents provides sensitive quantitative readouts.

Clinical Relevance

This bridging ELISA approach enables monitoring of patients who may develop neutralizing antibodies against nirsevimab, which could potentially impact the therapeutic's efficacy in preventing RSV disease. Importantly, the assay can detect both free ADAs and those present in immune complexes, providing comprehensive immunogenicity assessment throughout the patient's treatment course.

The high sensitivity of bridging ELISAs makes them particularly suitable for detecting low-level ADA responses, which is crucial given nirsevimab's role as a preventive therapy where even modest immune responses could affect protection duration.

References & Citations

1. Hammitt LL, Dagan R, Yuan Y, et al. N Engl J Med. 386(9):837-846. 2022.
2. McLellan JS, Ray WC, Peeples ME. Curr Top Microbiol Immunol. 372:383-104. 2013.
3. Keam SJ. Drugs. 83(2):181-187. 2023.
4. Zhu Q, McLellan JS, Kallewaard NL, et al. Sci Transl Med. 9(388):eaaj1928. 2017.
5. Domachowske JB, Khan AA, Esser MT, et al. Pediatr Infect Dis J. 37(9):886-892. 2018.
6. Zhu Q, Lu B, McTamney P, et al. J Infect Dis. 218(4):572-580. 2018.
7. Griffin MP, Yuan Y, Takas T, et al. N Engl J Med. 383(5):415-425. 2020.
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Disclaimer AlertProducts are for research use only. Not for use in diagnostic or therapeutic procedures.