Bispecific Single Domain Antibody (SdAb) Development Solution

During the past decades, a phenomenal evolution of bispecific antibodies (bsAbs) has been observed for both therapeutic and diagnostic applications. To meet the growing demand for bispecific antibodies, Creative Biolabs has established one-stop solutions to generate a series of novel bispecific antibodies that are based on the single domain antibody (sdAb). In terms of our extensive experience in V_HH antibody discovery and development, our scientists are confident in developing bispecific V_HH antibodies or other multivalent V_HH antibody formats with high affinity and low immunogenicity for your projects.

Why Choose Bispecific Single Domain Antibody or Other Multivalent V_HH Antibody Formats?

BsAb is an artificial protein that can simultaneously recognize two different epitopes either on the same or different antigens. In recent years, bispecific antibodies have become increasingly of interest for a broad spectrum of applications and have been evaluated as potential treatments for a variety of indications, such as chronic inflammatory diseases, neurodegeneration, bleeding disorders, autoimmunity, cancers, and infections.

To further strengthen the advantages of bsAb, Creative Biolabs can employ V_HH antibodies as a specific source. V_HH antibody is a kind of antibody fragment consisting of a single monomeric variable antibody domain and lacking the light chain and CH domain of the heavy chain in the conventional Fab region. Compared with conventional antibodies, V_HH antibodies take great advantage of their smaller size (~ 15 kDa), better penetrability, and high yield, which can be a better module for bispecific antibody design and manufacture. The conjugation of two or more V_HH antibodies results in bivalent, trivalent, or even multivalent molecules with one or more specificities. For instance, two V_HH molecules can be fused with a flexible linker derived from their native IgG format (from the hinge regions). Moreover, a multivalent V_HH antibody with one site directed against serum albumin can be a general approach for half-life extension, a similar idea can also contribute to delivering a target-specific component to pass the biological barriers.

Typical Features of Bispecific V_HH Antibodies

Typical Pathway for Bispecific V_HH Antibody Development

Features of One-Stop Bispecific V_HH Antibody Development

As an extremely fast-growing field, bispecific V_HH antibody development presents great potential for both therapeutic and diagnostic purposes. Creative Biolabs can provide one-stop solutions to discover and develop the best-fit bispecific V_HH antibodies for your purpose. If you are interested in learning more about our solutions, please do not hesitate to contact us.

Published Data

This study investigated the potential application of the Fab x sdAbs-Fc with the same bispecific format, but designed with a hinge region varied in length. To study the influence of modulating the hinge region between the heavy chain backbone of the antibody molecule and the Fab arm, two mCD3E × mEGFR bispecific antibodies were generated with different hinge designs, one with a shorter hinge (TbsAb-short form) and the other with a longer hinge design (TbsAb-long form). Generally speaking, decreasing the distance between T cells and tumor cells leads to stronger T cell activation and, in turn, better tumor cell death. In the results, the TbsAb-short form showed remarkably better potency in modulating redirected T-cell killing and activation of T cells, meanwhile facilitating the aggregations between T cells and tumor cells, compared to the TbsAb-long form. Rather than comparing multiple bispecific forms, this study indicated that even tweaking a dozen amino acids in the hinge region of the same bispecific format could have a significant impact on its cytotoxicity, suggesting that a shorter hinge design may be beneficial when creating human Fab x sdAb-Fc TbsAb for cancer therapy. This has provided spirited inspiration and new thought for the design and development of bispecific V_HH antibodies.

FAQ

1. What is a bispecific single-domain antibody?

A bispecific single-domain antibody is a type of antibody fragment that can simultaneously bind to two distinct epitopes. Unlike traditional antibodies that have two identical antigen-binding sites, bispecific V_HH antibodies are engineered to have two different binding sites, allowing them to bring two different molecules into proximity or significant enhance the affinity against one target.

2. How are bispecific V_HH antibodies constructed?

Bispecific V_HH antibodies are constructed by genetically fusing two single-domain antibodies each with a unique specificity. This fusion can be achieved using a flexible peptide linker or more advanced molecular engineering techniques to ensure the correct folding and functionality of each binding site.

3. What are the advantages of using bispecific V_HH antibodies over traditional monoclonal antibodies?

Firstly, the size of the V_HH antibody (~ 15 kDa) is much smaller compared to the traditional one (~ 150 kDa), leading to improvement of their tissue penetration. Secondly, V_HH antibodies are usually stable and less susceptible to extreme pH and high temperatures. Besides, owing to their small size, V_HH antibodies can access epitopes that are inaccessible to larger antibodies. Moreover, the production of V_HH antibodies can be applied with microbial systems like E. coli or yeast, making it more cost-effective and efficient. Last but not least, bispecific V_HH antibodies are designed to simultaneously bind to two different targets, offering more versatile therapeutic options.

4. What role do linkers play in the functionality of bispecific V_HH antibodies?

Linkers are crucial in bispecific V_HH antibodies as they connect the two single-domain antibodies and ensure that both can fold correctly and function independently. The linker can tremendously affect the stability, solubility, and flexibility of the bispecific sdAb. Typically, flexible polypeptide linkers are used to allow independent movement and optimal binding to both targets, minimizing steric hindrance as well.

5. Can bispecific V_HH antibodies be used for diagnostic purposes?

Yes, bispecific V_HH antibodies can be utilized for diagnostic purposes. Their ability to bind two different antigens makes them suitable for use in various diagnostic assays, such as targeted imaging and biomarker detection. For instance, bispecific V_HH antibodies can be designed to target a disease-specific antigen and a reporter molecule like a fluorescent dye, enhancing the specificity and sensitivity of diagnostic imaging tools.

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