VHH Antibody Discovery Service

As a professional supplier in the field of phage display and antibody engineering, Alpha Lifetech Inc. can offer rapid production of single-domain antibody libraries. Our proprietary phage display technologies allow scientists to specify their requirements for expression and characterization.

What Is VHH Single-Domain Antibody?

Single-domain antibody (sdAb), or nanobody, VHH, is part of a class of recombinant antibody fragments, representing the smallest antibody that was proven of great usefulness. With a molecular weight of 12-15 kDa, single-domain antibodies, which consist only of a single heavy-chain variable domain and engineer from single monomeric variable domains of either camelids' heavy-chain antibody (VHH) or cartilaginous fishes' IgNAR (VNAR) without loss of antigen-binding ability.

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Single-domain antibodies have many advantages: High affinity with small-sized antibodies, good physicochemical properties, and easy downstream engineering . The characteristics of single-domain and ease of gene manipulation of the single-domain antibody make it suitable for affinity maturation in vitro.

Comparison between VHH single domain antibody and conventional antibody

	Single Domain Antibody	Conventional Antibody
Size	Small, only one heavy chain domain (V_HH)~13 kDa	Large, both heavy and light chains~120-150 kDa
Antigen Binding Site	Monomeric V_HH subunit required for antigen binding	Both chains required for antigen binding and stability
Downstream	Highly amenable to downstream engineering	Relatively low engineering flexibility due to complex structure
Stability	Maintains stability and potency at extreme pH and temperatures	Cannot tolerate extreme pH or temperatures
Administration way	Multiple routes of administration	Administered through injection, cannot be administered orally
Production	Easy to manufacture in yeast or microbial systems	Challenging and costly to manufacture

What We Can Offer?

Construction of Immunized Single Domain Antibody Library
The scientists at Alpha Lifetech Inc. have extensive experience in constructing and expressing recombinant antibodies based on our proprietary phage display platform. An immunized single-domain antibody library is suitable for the generation of high-affinity and antigen-special VHH or NAR V antibodies, thus avoiding time-consuming in vitro antibody affinity maturation effort. Here, we produce an antigen-special single-domain antibody library for our clients from immunized alpacas, camels, llamas or sharks, and even humans (PBL cells activated by antigens in vitro). By reverse transcription and polymerase chain reaction, a library of single-domain antibodies containing 10-100 million clones is regularly produced.

Construction of Synthetic Single Domain Antibody Library
Synthetic single-domain antibody libraries often developed from the CDR1 and CDR3 of either naïve VHH or VNAR. This synthetic antibody library is by definition a naïve library and has a high complexity of 3x10^10 VHHs ensuring a very satisfying diversity. It is naïve so it does not require llama or shark immunization. This helps us save a lot of time to get a specific antibody and makes possible antibody selection for non-immunogenic or conserved proteins. Such synthetic libraries represent a good source of single-domain antibodies against self, non-immunogenic, and toxic antigens since the libraries are usually sufficiently vast and diverse. In case the selection of high-soluble single-domain antibodies is a concern, we have designed a shuttle phagemid vector system, including several phagemids, which can express the single-domain antibodies in E. coli (yeast) or display them on the surface of phage particles.

If you have any questions, please feel free to contact us at any time.