Nanobodies (VHH antibodies) possess unique physicochemical properties that make them ideal therapeutic molecules and clinical diagnostic tools. The discovery of nanobodies requires screening of VHH libraries. Currently, VHH libraries can be categorized into three types: naïve library, immune library, and synthetic library.
Naïve Library: VHH genes are derived from B lymphocytes of non-immunized camelids.
Immune Library: VHH genes originate from B lymphocytes of camelids immunized with specific antigens.
Synthetic Library: VHH genes are designed and synthesized in vitro, eliminating the need for animal immunization and blood collection, and subsequently assembled using gene engineering technologies.
Compared to immune libraries, naïve libraries offer several advantages:
Enables selection of antibodies against self-antigens, non-immunogenic, or toxic targets.
A single naïve library can be screened against multiple antigens, reducing antibody discovery costs.
No need to start with immunized animals, significantly shortening antibody development timelines.
Limitations:
Antibodies have not undergone in vivo affinity maturation.
Typically, obtained antibodies have lower affinities; the best affinities generally reach ~10⁸ M⁻¹.
| Library Type | Source | Advantages | Limitations | Suitable Applications |
|---|---|---|---|---|
| Naïve Library | Non-immunized animal B cells | Multi-target, no immunization required, short development cycle | Relatively lower affinity | Toxic or low-immunogenic antigens |
| Immune Library | B cells from immunized animals | High affinity, matured antibodies | Long immunization cycle | High-affinity monoclonal antibody for single antigen |
| Synthetic Library | Artificially designed VHH genes | Customizable, no animals required | Complex design, potential instability | Engineered proteins or structural protein targets |
Diverse species sources: Library includes dromedary camels, alpacas, and llamas. Donor animals: >20 for camels and llamas, >100 for alpacas.
Large library size: Total library capacity reaches 10¹¹ clones.
High library quality: Excellent insertion rate and diversity.
Library validation: Verified through insertion rate testing and NGS sequencing analysis to ensure suitability for screening nanobodies against diverse antigens.
Library Data Visualization:
A: Efficient PBMC isolation
B: Naïve library VHH insertion rate detection
C: Sanger sequencing diversity analysis
Table 1: Alpvhhs Naïve Library NGS analysis result
Diverse Sourcing: PBMCs isolated from over 100 alpacas and 20+ camels/llamas for vast genetic base.
Nested PCR Amplification: Specific primers target VHH framework regions to precisely amplify VHH repertoire while excluding contamination.
High-Efficiency Transformation: Optimized display vectors and electroporation achieve library capacity of 10¹¹ clones.
Quality Validation: Every library undergoes NGS sequencing and insertion rate testing.
Ideal for: High-throughput initial screening
Core concept: Exploiting throughput advantages for ultra-large libraries (~10¹¹ clones)
Suitable targets: Soluble proteins and conventional antigens
Output: Rapid enrichment of positive clones through 2–4 rounds of binding, elution, and amplification
Ideal for: Complex epitopes and precise selection
Core concept: Eukaryotic expression ensures proper protein folding; FACS enables single-clone precision sorting
Suitable targets: GPCRs, multi-transmembrane proteins, conformationally dependent antigens; also for high-affinity mutant evolution
Since 2019, SARS-CoV-2 has spread worldwide. To obtain neutralizing nanobodies against SARS-CoV-2, the AlpVHHs naïve library was used to screen the S protein RBD via solid-phase panning.
After 2 rounds, 192 clones were selected in monoclonal analysis.
104 positive clones were obtained (54% positivity rate).
Sequencing revealed 12 unique CDR3 nanobody sequences.
Subsequent expression verification confirmed strong neutralizing activity against SARS-CoV-2.
Table 2: Naïve library RBD phage ELISA results
Rounds 1–2: Preliminary enrichment using antigen-coated magnetic beads
Rounds 3–4: FACS-based precise selection
Result: Obtained nanomolar-affinity, high-specificity antibodies
Fig 2. Flow Cytometry Profiles of Screening Products from Rounds 1-4
A) Blank control – baseline signal without sample.
B) Negative control – dye only, showing background signal.
C) Round 1 – magnetic bead product with 100 nM target, initial enrichment.
D) Round 2 – further enriched product, improved specificity.
E) Round 3 – high specificity and purity after sorting.
F) Round 4 – final selection of highly specific and pure antibodies.
Horizontal axis: fluorescence of expression tag (488 nm); Vertical axis: target binding (650 nm).
AlpVHHs specializes in nanobody (VHH) discovery and custom CRO services, providing rapid and efficient antibody candidate discovery through high-quality libraries and advanced screening platforms.
Core Strengths: Over 10 years of experience, successfully delivered 1000+ projects, supported 20+ IND approvals, and developed 2000+ nanobody products.
Library Resources: Proprietary Large VHH Library series, including naïve, immune, and synthetic libraries.
Technology Platforms: Dual-platform support with Phage Display and Yeast Display.
Service Model: Custom CRO service covering entire process from library screening to candidate validation.
Come and start your nanobody research now:
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Browse Complete Large VHH Library Product Series
| Code | Description | Applications |
|---|---|---|
| AlpSDAb-P | Phage display based Naïve VHH Library from Alpaca | phage display library for screening |
| CamSDAb-P | Phage dispaly based Naïve VHH Library from Camel | phage display library for screening |
| CamSDAb-Y | Yeast Display Based Naïve VHH Library from Camel | yeast display library for screening |
| LlaSDAb-P | Phage display based Naïve VHH Library from llama | phage display library for screening |
