Antibody Affinity Measurement Service

Background Services Published Data FAQ Resources

With our excellent scientists, Creative Biolabs has accumulated strong expertise and extensive experience in affinity and kinetics measurement for specific antibodies. Creative Biolabs provides Surface Plasmon Resonance (SPR) and Bio-Layer Interferometry (BLI) based affinity measurements in a label-free and high-efficiency mode.

Background

Antibody, also known as immunoglobulin, is a Y-shaped protein. Among the five classes of immunoglobulin (including IgA, IgD, IgE, IgG and IgM), IgG plays an outstanding role in immune system. Each individual IgG molecule is unique to target a specific epitope. However, some people have normal levels of immunoglobulins and all forms of IgG, they do not generate sufficient specific IgG antibodies that can protect human from some viruses and bacteria (lack or low level of these IgG molecules). Thus, we call these molecules “specific antibodies”, and they are usually generated to respond to bacteria and viruses, or through the exposure to vaccines. Therefore, specific antibodies are applied extensively in diagnostics.

Those people, who cannot produce specific antibodies in responding to polysaccharide antigens, are diagnosed with specific antibody deficiency (SAD). SAD was fisrt discovered in a group of patients in the early 1980s, and it was one of the commonly identified immune deficiencies among patients presenting severe sinopulmonary infections. Although specific IgG antibodies are important in resisting infections, other immunoglobulin members of our immune system also play vital roles in defensing bacteria and viruses. If these immunoglobulin members work well, the patients with low specific antibodies may rarely be sick. However, antibodies of certain IgG subclasses can interact readily with the complement immune system, immunoglobulin of other subclasses interact poorly with the complement system. In this case, the inability of producing antibodies of a specific subclass can render the individual susceptible to certain kinds of infections. So, it is important to determine the affinity of the specific antibodies.

Affinity Measurement for Specific Antibodies

Creative Biolabs can provide the following affinity measurement for specific antibodies but not limited to:

Determination of direct antibody-antigen interactions.
Full kinetics analysis, such as detailed binding kenitic data.
Clinical presentation or diagnosis of specific antibody deficiency.
Scouting analysis.
Isotype determination of specific antibodies.

We can efficiently identify antibody isotypes using Biacore, ProteOn and Octet systems. For instance, when Octect system is applied, the biosensor immobilized with an certain type of anti-species antibody will capture a specific isotype of antibody from a crude sample, such as a hybridoma supernatant. Therefore, identifying the isotype of a specific antibody is achieved.

Figure 1. Diagram of kinetics analysis on Octet system. A biotinylated anti-mouse Fc antibody was immobilized onto Streptavidin biosensors.

Creative Biolabs can provide various antibody affinity measurement services based on SPR and BLI technologies. Please feel free to contact us for a detailed quote.

Other optional Antibody Affinity Measurement Services:

Published Data

Affinity Measurement of ZIKV Envelope Domain-Specific Antibodies

Fig. 2 Determination of ZIKV E-specific antibodies in the sera. (Sami Akhras, 2019)

Neutralizing and non-neutralizing epitopes are essential for the development of a protective antibody detection system for the Zika virus. Here, the researchers reported six different polyclonal antibodies against the Zika virus envelope (E) protein. These six antibodies bind to the surface of isolated Zika virus E protein and Zika virus particles, but they do not have a strong neutralization effect. Surface plasmon resonance measurements showed that these antibodies had a high affinity for the Zika virus E protein. The epitope map showed that the epitopes were distributed in the three E domains of ZIKV and had seven binding sites. These binding sites partially overlap with the epitopes recognized by neutralizing antibodies previously described, which is consistent with their lack of strong neutralizing activity. These data are helpful to understand the distribution of neutralizing and non/weak neutralizing epitopes in the ZIKV E protein, and provide a theoretical basis for the detection of neutralizing antibodies in the design and development of the ZIKV vaccine.

References

A. Saxon et al. (1980). In vitro analysis of humoral immunity in antibody deficiency with normal immunoglobulins. Clin. Immunol. Immunopathol. 17(2): 235-244.
A. Tlili et al. (2006). Impedance spectroscopy and affinity measurement of specific antibody–antigen interaction. Materials Science and Engineering C. 26: 546-550.
P. Estep et al. (2013). High throughput solution-based measurement of antibody-antigen a nity and epitope binning. Landes Bioscience. 5 (2): 270-278.
Akhras, Sami, et al. "ZIKV envelope domain-specific antibodies: production, purification and characterization." Viruses 11.8 (2019): 748.

FAQ

What methods are commonly used to measure the affinity and kinetics of specific antibodies against viruses?
The most commonly used methods for measuring the affinity and kinetics of antibodies against viruses include Surface Plasmon Resonance (SPR) and Bio-Layer Interferometry (BLI). SPR is highly sensitive and can provide real-time measurements of binding affinity and kinetics, allowing researchers to understand how quickly an antibody binds to and dissociates from a virus. BLI also offers real-time, label-free analysis and is particularly useful for measuring interactions in crude or complex matrices.
Can you explain how the measurement of antibody kinetics can impact the development of treatments against bacterial infections?
The measurement of antibody kinetics is crucial in the development of antibacterial treatments because it provides insights into the binding efficiency and duration of antibody-antigen interactions. Faster association rates indicate that an antibody can quickly bind to bacteria, potentially neutralizing or inhibiting them more effectively. Moreover, a longer dissociation time suggests that the antibody remains bound longer, enhancing its therapeutic effects. Understanding these parameters helps in selecting and optimizing antibodies that are most effective against specific bacterial targets.
How does temperature affect the affinity and kinetics measurements of antibodies targeting viruses?
Temperature plays a significant role in the affinity and kinetics of antibody-antigen interactions. Higher temperatures generally increase the rate of molecular interactions, potentially speeding up both the association and dissociation rates of antibodies with viral antigens. However, excessively high temperatures can also destabilize the antibody, reducing its binding affinity. Careful control of temperature is crucial during experiments to ensure accurate and reproducible measurements of antibody performance.
What are the implications of high-affinity antibody binding in the context of bacterial infections?
High-affinity antibody binding to bacterial antigens is often correlated with more effective immune responses. Antibodies with higher affinity can bind more tightly and remain attached to bacterial surfaces longer, enhancing opsonization and facilitating more efficient phagocytosis by immune cells. This can lead to improved clearance of bacterial infections. Moreover, high-affinity antibodies are more selective, reducing the likelihood of cross-reactivity with human tissues and minimizing potential side effects.
What role does the concentration of antibodies play in the kinetics and affinity measurements against bacterial targets?
The concentration of antibodies can significantly influence the observed kinetics and affinity measurements during antibody-bacterial interactions. At higher concentrations, antibodies are more likely to encounter and bind to bacterial antigens, which can artificially enhance the perceived affinity due to avidity effects. Conversely, too low a concentration might not adequately represent the binding capability under physiological conditions. Thus, optimizing antibody concentration is crucial for accurate kinetics and affinity assessment, ensuring that the measurements reflect true monovalent interactions.
How does the valency of antibodies affect their binding kinetics and affinity for viral antigens?
The valency of antibodies, referring to the number of antigen-binding sites, significantly affects their binding kinetics and affinity for viral antigens. Multivalent antibodies can bind to multiple epitopes on a single virus or across different viruses, leading to a stronger overall binding due to the cumulative effect of multiple interactions. This can result in faster apparent association rates and slower dissociation rates, enhancing the overall stability of the antibody-virus complex. Such properties are particularly advantageous in neutralizing viruses, as they prevent viral entry into host cells more effectively.
Is there a preferred analytical technique for determining the dissociation constant (Kd) of antibodies against viral targets?
Surface Plasmon Resonance (SPR) is often considered the gold standard for determining the dissociation constant (Kd) of antibodies against viral targets. SPR allows for real-time monitoring of the interaction between the antibody and antigen, providing precise measurements of both association and dissociation rates, which are essential for calculating Kd. This technique is highly sensitive, enabling the detection of interactions with low affinity, and can be used with crude or complex samples.
What impact do buffer conditions have on the affinity and kinetics measurements of antibodies against bacterial antigens?
Buffer conditions, including pH, ionic strength, and the presence of other molecules, can significantly impact the affinity and kinetics of antibody interactions with bacterial antigens. Optimal buffer conditions help maintain the structural integrity of both the antibody and antigen, ensuring that the binding interactions reflect physiological conditions. Deviations in pH can alter the charge and solubility of the antibody and antigen, potentially leading to changes in binding characteristics. Similarly, high ionic strength can shield electrostatic interactions, influencing the association and dissociation rates.