Overview of Custom Antibody Conjugation Services
Custom antibody conjugation services provide an outsourced solution for researchers and organizations that need antibody conjugates with defined quality attributes but lack the in-house expertise, equipment, or time to perform conjugation and purification themselves. The service model ranges from simple one-step labeling reactions at research scale to multi-step ADC development programs with cGMP manufacturing, offering flexibility to match each project's complexity, timeline, and regulatory requirements.
The value of professional conjugation services lies in three core areas. First, chemistry expertise: selecting the right conjugation strategy for a given antibody, payload, and application requires understanding of reactive functional groups, linker chemistry, stoichiometry control, and the interplay between conjugation conditions and antibody activity. An experienced conjugation team can evaluate the antibody sequence, buffer composition, and intended payload to recommend a strategy that maximizes conjugate performance while minimizing risk of affinity loss or aggregation. Second, analytical capability: measuring degree of labeling (DOL), drug-to-antibody ratio (DAR), conjugate purity, binding activity, and aggregation requires specialized instruments and validated methods that most research laboratories do not maintain. Professional services include analytical characterization as a standard deliverable, providing quantitative data that support downstream experimental design and quality assessment. Third, quality systems: for projects that require cGMP manufacturing, a compliant facility with documentation, traceability, and change control is essential for regulatory submissions and for ensuring that conjugate material produced at different times meets the same specifications.
Antibody conjugation services are not limited to a single chemistry or payload type. The service portfolio spans the full range of conjugation approaches, from conventional amine-reactive and thiol-reactive chemical methods to site-specific enzymatic strategies, and covers payloads including fluorescent dyes, enzymes, biotin, drugs, polymers, oligonucleotides, and nanoparticles. Each project begins with a consultation to define the conjugation objective, evaluate the starting antibody, select an appropriate conjugation chemistry, and establish the quality specifications that the final conjugate must meet. This consultative approach ensures that every conjugate is designed for its intended application rather than produced by a generic labeling protocol that may not address the specific requirements of the project.
Chemistry expertiseProfessional conjugation teams evaluate antibody structure, buffer composition, and payload chemistry to recommend the optimal conjugation strategy, ensuring that the chosen approach preserves antigen-binding activity while achieving the desired labeling stoichiometry.
Analytical characterizationDOL/DAR measurement by UV-Vis or mass spectrometry, conjugate purity by HPLC or SDS-PAGE, binding activity by ELISA or SPR, and aggregation by size-exclusion chromatography are included as standard deliverables for research-scale and cGMP projects.
cGMP quality systemsFor IND-enabling projects, cGMP manufacturing provides validated processes, batch records, raw material traceability, change control, and QC release testing under a compliant quality management system.
Scalable deliveryProjects can start at research scale (micrograms to milligrams) and transition to cGMP scale (hundreds of milligrams to grams) as development progresses, with consistent chemistry and quality specifications maintained across scales.
Service Portfolio for Custom Antibody Conjugation
The service portfolio for custom antibody conjugation encompasses a comprehensive range of conjugation chemistries, payload types, and quality levels designed to address projects from simple fluorescent labeling to complex cGMP ADC manufacturing. Each service category is defined by its conjugation chemistry, the payloads it supports, the scale at which it operates, and the quality documentation that accompanies the final product. Understanding the full portfolio allows researchers to select the service tier that matches their project requirements and to plan for scale-up as development progresses.
| Service Category | Conjugation Chemistry | Typical Payloads | Scale | Quality Level |
|---|
| Fluorescent labeling | NHS ester, maleimide, periodate oxidation | FITC, Alexa Fluor, Cy dyes, Pacific Blue, APC | Research (micrograms to milligrams) | Analytical characterization with DOL report |
| Enzyme conjugation | NHS ester, maleimide, periodate oxidation, crosslinkers | HRP, alkaline phosphatase, beta-galactosidase | Research (micrograms to milligrams) | Analytical characterization with activity assay |
| Biotinylation | NHS ester, maleimide | Biotin, long-chain biotin, sulfo-NHS-biotin | Research (micrograms to milligrams) | Analytical characterization with DOL report |
| PEG conjugation | NHS ester, maleimide, click chemistry | PEG (5 kDa to 40 kDa), branched PEG | Research (micrograms to milligrams) | Analytical characterization with DOL report |
| ADC development | Maleimide, click, enzymatic (sortase, mTG) | Maytansinoids, auristatins, PBD dimers, duocarmycins | Research to preclinical (milligrams to grams) | Full characterization package with DAR, purity, binding, stability |
| cGMP bioconjugation | Per validated SOP (maleimide, click, enzymatic) | Per project specification (drugs, dyes, enzymes, polymers) | Preclinical to clinical (hundreds of mg to grams) | cGMP with full documentation, QC release, stability program |
| Protein-antibody conjugation | Sortase, click chemistry, heterobifunctional crosslinkers | Recombinant proteins, enzymes, cytokines | Research (micrograms to milligrams) | Analytical characterization with activity and purity |
| Glycosylation remodeling | Enzymatic (glycosyltransferases, glycosidases) | Modified glycans, azide-modified sugars | Research (micrograms to milligrams) | Analytical characterization with glycan profiling |
The portfolio structure enables a seamless transition from research-scale conjugation to cGMP manufacturing. A project that begins with fluorescent labeling at the microgram level can later transition to the same conjugation chemistry under cGMP conditions when the conjugate moves into IND-enabling studies. The underlying chemistry remains consistent, but the quality system, documentation, and scale change to meet regulatory requirements. This continuity avoids the need to redevelop the conjugation process when the project advances to later development stages, saving time and reducing the risk of process-related surprises during cGMP transfer.
Chemical Conjugation Services for Antibodies
Chemical conjugation remains the most widely used approach for antibody modification. These methods exploit naturally occurring functional groups on the antibody surface—lysine amines, cysteine thiols, and carbohydrate-derived aldehydes—to form covalent bonds with activated payload molecules. Professional antibody conjugation services offer a full menu of chemical approaches, each matched to specific payload types and application requirements, with buffer optimization, stoichiometry control, and purification included as part of the service.
The choice of chemical conjugation method depends on several factors: the reactive groups available on the antibody, the functional groups present on the payload, the desired degree of labeling, the tolerance for conjugate heterogeneity, and the stability requirements for the conjugate under storage and assay conditions. For many research applications, amine-reactive NHS ester chemistry provides a straightforward and reliable labeling pathway. For applications that require more defined stoichiometry or placement, thiol-reactive maleimide chemistry or click chemistry approaches offer greater control. Professional conjugation services evaluate these factors for each project and recommend the chemistry that best balances labeling efficiency, product homogeneity, and functional activity retention.
NHS ester conjugationNHS ester reagents react with primary amines on lysine residues and the antibody N-terminus at pH 7.2-9.0. This is the most commonly used chemistry for fluorescent labeling, biotinylation, and enzyme conjugation. It produces a stable amide bond and is compatible with a wide range of NHS-activated dyes, biotin derivatives, and crosslinkers. The primary limitation is heterogeneity: lysine residues are distributed across the entire antibody surface, and payloads attached near the antigen-binding site may reduce binding affinity.
Maleimide-thiol conjugationMaleimide reagents react with free cysteine thiols at pH 6.5-7.5. After partial reduction of inter-chain disulfide bonds, 2-8 free thiols become available for conjugation. Maleimide chemistry produces more defined conjugates than amine-directed methods because the number and position of reactive thiols are constrained by the disulfide bond architecture. This approach is the standard for ADC conjugation and for applications requiring controlled DAR values.
Periodate oxidation and hydrazide conjugationSodium periodate oxidizes Fc glycans to generate aldehyde groups, which react with hydrazide or aminooxy-functionalized payloads. Glycan-directed conjugation is inherently site-specific because the Fc carbohydrate is remote from the antigen-binding site, minimizing the risk of affinity loss. This method is particularly useful for creating conjugates where the Fab region must remain completely unmodified to preserve binding activity at full strength.
Click chemistry (CuAAC and SPAAC)Copper-catalyzed azide-alkyne cycloaddition (CuAAC) and strain-promoted azide-alkyne cycloaddition (SPAAC) enable bioorthogonal conjugation between azide- and alkyne-functionalized components. Click chemistry produces high-purity conjugates with excellent yield under mild conditions. SPAAC, which does not require a copper catalyst, is compatible with sensitive biological molecules. Both approaches are increasingly used for site-specific conjugation when azide or alkyne handles have been introduced through protein engineering or enzymatic modification.
Beyond these four primary methods, chemical conjugation services also support heterobifunctional crosslinker chemistry, where a single crosslinker molecule carries two different reactive groups (for example, NHS ester and maleimide, or NHS ester and azide) to connect two distinct molecular partners. This approach is essential for creating protein-antibody conjugates where the antibody and the protein payload present different reactive handles. Professional services manage the sequential reaction steps, intermediate purification, and final conjugate characterization required for these multi-component assemblies.
Enzymatic Conjugation Services for Site-Specific Modification
Enzymatic conjugation methods use biocatalysts to achieve site-selective antibody modification, producing conjugates with defined stoichiometry and attachment positions. These approaches are increasingly important for ADC development and for any application where conjugate homogeneity directly impacts performance. Professional conjugation services offer enzymatic strategies that complement chemical methods, enabling projects that require precise DAR control, payload placement at a single defined site, or conjugation under conditions that preserve antibody activity.
The principle behind enzymatic conjugation is that certain enzymes recognize short peptide tags or specific structural motifs on the antibody and catalyze the formation of a covalent bond between the antibody and a payload molecule. Because the enzymatic recognition sequence can be placed at a defined position through protein engineering, and because the enzyme typically processes one site per antibody molecule, the resulting conjugate has a defined DAR and a uniform attachment position. This uniformity simplifies analytical characterization, improves batch reproducibility, and eliminates the variability in binding activity that arises from random attachment near the antigen-binding site.
Sortase-mediated ligationSortase A recognizes the LPXTG motif at the antibody C-terminus and catalyzes transpeptidation with an oligoglycine-modified payload, replacing the C-terminal residues and forming a stable peptide bond. Sortase conjugation produces a single conjugate species with DAR = 1 at a defined C-terminal position, making it ideal for applications requiring precise stoichiometry and for creating Fab or scFv conjugates where the modification site is remote from the antigen-binding domain.
Microbial transglutaminase (mTG) catalysismTG catalyzes an amide bond between a glutamine residue in the antibody Fc region and a primary amine on the payload. When a glutamine tag is engineered into the Fc or when the native Fc glycan is enzymatically removed to expose an underlying glutamine, mTG achieves site-specific conjugation with DAR = 2 or DAR = 4. This method is widely used in ADC manufacturing because it produces homogeneous conjugates under mild conditions without requiring reducing agents that might destabilize the antibody.
Formylglycine-generating enzyme (FGE)FGE converts a cysteine residue within the CXPXR motif into a formylglycine (aldehyde), providing a bioorthogonal reactive handle for oxime or hydrazone ligation with aminooxy- or hydrazide-functionalized payloads. The FGE-generated aldehyde is a unique functional group not found elsewhere on the antibody, ensuring chemoselective conjugation at the engineered site. This approach is particularly valuable for creating ADCs where the payload must be released in the intracellular environment through a cleavable linker.
Glycosyltransferase-based remodelingEndoglycosidases and glycosyltransferases can remodel the Fc glycan to introduce modified sugar residues bearing azide, ketone, or other reactive handles for downstream conjugation. Antibody glycosylation remodeling preserves the Fc structure while providing a defined conjugation site on the glycan, enabling site-specific modification without protein engineering of the polypeptide chain.
Enzymatic conjugation services typically begin with an evaluation of the antibody format and sequence to determine whether the required recognition tag is already present or needs to be introduced through protein engineering. For antibodies that already carry an appropriate tag, conjugation can proceed directly. For antibodies that require engineering, the service team collaborates with the client to design and produce the modified antibody before proceeding to conjugation. This two-step approach ensures that the final conjugate benefits from the full site specificity of enzymatic chemistry, even when the starting antibody does not initially carry the necessary recognition motif.
Antibody-Drug Conjugate Development Services
ADC development represents one of the most complex applications of antibody conjugation technology. Professional antibody-drug conjugation services address the full development workflow, from initial conjugation chemistry screening through process optimization, scale-up, and cGMP manufacturing for IND-enabling studies. Each step requires careful coordination of antibody engineering, linker-payload synthesis, conjugation chemistry, purification, and analytical characterization to produce a conjugate that meets defined specifications for DAR, purity, binding activity, and stability.
The ADC development process begins with conjugation chemistry screening, where multiple conjugation approaches (maleimide-thiol, click chemistry, enzymatic methods) are evaluated side by side using the same antibody and payload to identify the chemistry that produces the best balance of DAR distribution, conjugate homogeneity, binding retention, and stability. This screening phase typically produces 3-5 conjugate variants that are characterized in parallel, allowing the development team to select the lead conjugation chemistry based on objective analytical data rather than assumption or precedent.
Once the lead conjugation chemistry is selected, process optimization focuses on achieving reproducible DAR, yield, and product quality across multiple runs. Key parameters include the molar ratio of payload to antibody, reaction time, temperature, pH, buffer composition, and quench conditions. The optimization goal is to establish a defined set of process parameters that consistently produce conjugate material within the specified DAR range (typically DAR 2-4 with a narrow distribution) and with recovery above the minimum threshold.
| Development Stage | Key Activities | Analytical Requirements | Typical Timeline |
|---|
| Conjugation screening | Evaluate 3-5 conjugation chemistries for DAR, homogeneity, binding retention, and stability | DAR distribution (HIC or LC-MS), SEC purity, ELISA or SPR binding, forced degradation stability | 2-4 weeks |
| Process optimization | Optimize stoichiometry, reaction conditions, and purification for reproducible DAR and yield | Reproducibility across 3+ runs, DAR within specified range, recovery above minimum threshold, aggregation below limit | 3-6 weeks |
| Scale-up | Transfer optimized process to larger scale (100 mg to 1 g) with defined equipment and parameters | Scale-dependent parameter confirmation, yield, DAR consistency, impurity profile | 2-4 weeks |
| cGMP manufacturing | Execute conjugation under cGMP conditions with validated process, full documentation, and change control | Batch records, QC release testing (DAR, purity, binding, aggregation, endotoxin, bioburden), stability program initiation | Project-specific |
Linker design is a critical component of ADC development that directly influences conjugate stability, payload release mechanism, and pharmacokinetic behavior in preclinical models. Professional ADC services provide linker selection support, evaluating cleavable linkers (acid-sensitive hydrazone, protease-sensitive Val-Cit and Val-Ala dipeptides, glutathione-sensitive disulfide) and non-cleavable linkers (thioether, amide) against the project's requirements for payload release kinetics, stability in circulation, and bystander effect potential. The linker chemistry is integrated with the conjugation chemistry: for example, a maleimide-Val-Cit-PAB-linker-payload construct connects through thiol-maleimide chemistry on the antibody side while releasing the payload through cathepsin-mediated proteolysis in the target cell.
cGMP Bioconjugation Manufacturing for Preclinical Supply
cGMP (current Good Manufacturing Practice) bioconjugation manufacturing provides the regulatory-compliant infrastructure for producing antibody conjugates intended for IND-enabling studies and beyond. cGMP bioconjugation manufacturing differs fundamentally from research-scale conjugation in three respects: process validation, documentation and traceability, and quality control systems. Each of these elements is required for regulatory submissions and must be in place before any conjugate material enters a preclinical study that supports a regulatory filing.
Process validation establishes that the conjugation process, when executed according to defined parameters, consistently produces material that meets predetermined specifications. This requires executing the process multiple times under controlled conditions, collecting analytical data on each batch, and demonstrating that critical quality attributes (DAR, purity, binding activity, aggregation) remain within specification across all runs. Process validation data form the basis for the manufacturing section of regulatory submissions and provide the evidence that the process is capable of producing conjugate material of defined quality.
Documentation and traceability requirements under cGMP extend to every aspect of the manufacturing process. Batch records document each step of the conjugation, purification, and QC testing process with timestamps, operator identification, and parameter values. Raw material traceability links every batch of conjugate to the specific lots of antibody, payload, linker, buffer components, and consumables used in its production. Change control ensures that any modification to the process, equipment, or materials is evaluated for its impact on product quality before implementation and is documented with appropriate justification and approval.
Quality control systems under cGMP include incoming material testing (identity, purity, and functional activity of the antibody and payload before conjugation), in-process controls (reaction parameters, intermediate purity checkpoints), and final product release testing (DAR, conjugate purity, binding activity, aggregation, endotoxin, bioburden, and appearance). The QC release specifications are established during process development and validated during process qualification, ensuring that each released batch meets the same quality standards.
Process validationMultiple conjugation runs under defined conditions demonstrate that the process consistently produces material within DAR, purity, binding, and aggregation specifications. Validation data support regulatory filings and establish confidence in process reproducibility.
Documentation and traceabilityBatch records, raw material certificates, equipment logs, and change control records provide full traceability from conjugate batch to source materials. This documentation chain is essential for regulatory compliance and for investigating any quality deviations.
QC release testingEach cGMP batch undergoes a defined panel of release tests covering DAR, purity by HPLC and SEC, binding activity by ELISA or SPR, aggregation by SEC-HPLC, endotoxin by LAL, bioburden, and visual appearance. Material is released only after all tests meet predetermined specifications.
Stability programcGMP batches are placed on a formal stability program under defined storage conditions (temperature, light protection, container format). Stability data are collected at predefined intervals and used to establish the conjugate shelf life and recommended storage conditions for regulatory submissions.
Project Workflow for Custom Antibody Conjugation Services
Every custom antibody conjugation project follows a structured workflow that ensures the conjugate meets defined quality specifications while accommodating the specific requirements of the antibody, payload, and application. The workflow begins with a project consultation and proceeds through antibody preparation, conjugation execution, purification, and analytical characterization before the final conjugate is delivered with a comprehensive data package.
1. Project consultationEvaluate the antibody format, buffer composition, and intended payload. Define conjugation objectives (target DOL/DAR, application, quality specifications). Recommend conjugation chemistry and establish the project plan, timeline, and deliverables.
2. Antibody preparationBuffer exchange to remove incompatible components (Tris, BSA, azide, glycerol). Concentration adjustment to the optimal range for the selected conjugation chemistry. Purity assessment and, if needed, additional purification before the conjugation reaction.
3. Conjugation executionExecute the conjugation reaction under optimized conditions. Control stoichiometry, pH, temperature, and reaction time according to the project plan. Quench the reaction at the defined endpoint and prepare for purification.
4. PurificationRemove unreacted free payload, reaction byproducts, and any aggregated material using size-exclusion chromatography, dialysis, spin filtration, or affinity-based methods. Verify free payload removal by absorbance monitoring or HPLC.
5. Characterization and QCMeasure DOL/DAR by UV-Vis absorbance ratio or mass spectrometry. Assess conjugate purity by HPLC or SDS-PAGE. Verify binding activity by ELISA or SPR. Check aggregation by SEC-HPLC. Compile the full data package for delivery.
For cGMP projects, the workflow incorporates additional quality system elements at each step. The project consultation includes a formal quality agreement that defines responsibilities, specifications, and change control procedures. Antibody preparation follows incoming material testing protocols. Conjugation execution is documented in batch records with real-time parameter recording. Purification uses qualified equipment and validated methods. Characterization and QC include release testing against predetermined specifications and formal data review before material release.
Technical Support and Consultation for Antibody Conjugation Projects
BOC Sciences provides comprehensive technical support throughout the antibody conjugation project lifecycle. From initial consultation on conjugation strategy to post-delivery characterization guidance, the support team ensures that each conjugate meets the performance requirements defined by the project and that the client has the information needed to use the conjugate effectively in downstream experiments.
Conjugation strategy consultationEvaluate the starting antibody, payload, and application to recommend the optimal conjugation chemistry. Consider buffer compatibility, desired DOL/DAR, tolerance for heterogeneity, stability requirements, and scale. Provide a written project plan with defined specifications and deliverables before work begins.
Buffer compatibility reviewAssess the antibody storage buffer for components that interfere with the selected conjugation chemistry. Provide buffer exchange protocols or perform buffer exchange as part of the service. Ensure that the antibody is in a compatible buffer at the correct concentration before conjugation.
Analytical characterization guidanceExplain the analytical methods used for characterization, the meaning of each metric (DOL, DAR, purity, binding, aggregation), and how these data inform conjugate performance in the intended application. Provide recommendations for conjugate handling, storage, and use based on the characterization results.
cGMP project managementFor cGMP projects, a dedicated project manager coordinates the quality agreement, batch record review, raw material qualification, process execution, QC release testing, and stability program. Regular status updates and milestone reviews ensure transparency and alignment throughout the manufacturing campaign.
Ready to Start Your Antibody Conjugation Project?
Whether you need a fluorescently labeled antibody for flow cytometry, an enzyme-conjugated detection reagent for ELISA, a biotinylated capture antibody for immunoprecipitation, a PEGylated antibody with extended circulation half-life, or a cGMP-manufactured ADC for IND-enabling studies, BOC Sciences provides the conjugation expertise, analytical characterization, and quality systems to deliver conjugates that meet your specifications.
- Custom fluorescent, enzymatic, biotin, PEG, and drug conjugation
- Chemical and enzymatic conjugation strategies available
- Full analytical characterization: DOL/DAR, purity, binding activity, aggregation
- Research-scale to cGMP manufacturing with consistent quality standards
- Technical consultation and project management throughout the project lifecycle
Frequently Asked Questions About Custom Antibody Conjugation Services
What types of payloads can be conjugated to antibodies through professional services?
Professional antibody conjugation services support a broad range of payload types including fluorescent dyes (FITC, Cy dyes, APC, Pacific Blue), enzymes (HRP, alkaline phosphatase, beta-galactosidase), biotin and biotin derivatives (long-chain biotin, sulfo-NHS-biotin), cytotoxic drugs for ADC development (maytansinoids, auristatins, PBD dimers, duocarmycins), PEG polymers (linear and branched, 5-40 kDa), oligonucleotides, nanoparticles, and chelators for radiometal labeling. The service team evaluates payload compatibility with the selected conjugation chemistry and recommends the optimal approach for each payload type.
How do I choose between chemical and enzymatic conjugation for my project?
Chemical conjugation (NHS ester, maleimide, periodate oxidation, click chemistry) is appropriate for most research applications where some degree of conjugate heterogeneity is acceptable and where the antibody does not require protein engineering. Enzymatic conjugation (sortase, transglutaminase, FGE) is preferred when the project requires defined DAR, site-specific payload placement, maximum conjugate homogeneity, or when the antibody is intended for therapeutic development where product definition is essential. Professional conjugation services provide consultation to help select the approach that best matches the project requirements.
What quality characterization data are provided with custom antibody conjugates?
Research-scale projects receive an analytical data package that includes DOL or DAR measurement by UV-Vis absorbance ratio or mass spectrometry, conjugate purity by HPLC or SDS-PAGE, binding activity assessment by ELISA or SPR, and aggregation analysis by SEC-HPLC. cGMP projects receive a full QC release package that includes all of these analyses plus endotoxin testing (LAL), bioburden assessment, visual appearance, and batch record documentation. Stability data are provided for cGMP batches under formal stability programs.
Can cGMP manufacturing be performed for any conjugation chemistry?
cGMP manufacturing requires a validated process with documented parameters, qualified raw materials, and reproducible product quality. Most conjugation chemistries used in research-scale projects can be transferred to cGMP conditions, provided the process is formally validated and the critical quality attributes are consistently within specification. The transfer from research to cGMP typically involves process optimization runs, equipment qualification, and validation batches before full cGMP production begins. Professional services manage this transition to ensure that the conjugation chemistry produces equivalent results under cGMP conditions.
What antibody formats are compatible with custom conjugation services?
Custom conjugation services support full-length IgG antibodies (all subclasses and species), Fab fragments, F(ab')2 fragments, single-chain variable fragments (scFv), and engineered antibody formats including Thiomab variants, bispecific antibodies, and antibody fusion proteins. Each format presents different reactive groups and structural constraints that influence the choice of conjugation chemistry. The service team evaluates the format-specific considerations and recommends the appropriate strategy for each antibody type.
What is the typical turnaround time for custom antibody conjugation projects?
Research-scale fluorescent labeling, biotinylation, and enzyme conjugation projects are typically completed within 1-3 weeks, depending on the conjugation chemistry, antibody preparation requirements, and characterization package. ADC development projects involving conjugation screening and process optimization require 4-10 weeks. cGMP manufacturing timelines are project-specific and depend on process validation status, raw material availability, and batch size. The service team provides a detailed timeline estimate during the project consultation phase.
How are antibody conjugates packaged and stored after production?
Fluorescent conjugates are packaged in light-protected containers with stabilizer (BSA or trehalose) and stored at 2-8 degrees C. Enzyme conjugates are typically lyophilized with stabilizer for long-term storage or supplied in liquid form with preservative for short-term use. ADC conjugates are stored frozen at -80 degrees C under inert atmosphere to prevent linker degradation. Biotinylated antibodies are stored at 2-8 degrees C or -20 degrees C. Storage conditions and recommended handling procedures are specified in the data package provided with each conjugate delivery.