Immunized versus naïve libraries
Immunized
vs
Naïve Libraries
When generating nanobodies, researchers typically rely on antibody fragment libraries to identify binders against a target of interest. These libraries are generally divided into two main categories: immunized libraries and naïve libraries.

Immunized libraries are constructed from animals that have been exposed to a specific antigen, allowing the immune system to generate enriched, target-specific antibody sequences. As a result, they often provide a strong starting point for discovering high-affinity binders against defined targets. In contrast, naïve libraries are built from non-immunized animals and contain a broader diversity of naturally occurring antibody sequences. They can be screened against a wide range of targets without the need for prior immunization, making them a flexible and efficient option for early-stage discovery.

The choice between the two library types depends on factors such as target characteristics, project timeline, desired affinity, and screening strategy.
Immunized libraries Naïve libraries
Species Camelids and sharks Camelids and sharks
Number of binders Higher High
Affinity of binders pM to Nm range nM to uM range
Potential immunogenicity
issues
Yes No
Animal use Yes No
Timelines 5–6 months (Camelids)
6.5–8.5 months (Sharks)
1.5–2 months
Features Challenging targets
Highly customizable
One stop solution
Animal free
Cost effective
Short lead time

Why use immunized
library service?

Nanobody library is typically generated from nanobody genes isolated from the PBMC of the immunized donors to clone the antigen-specific nanobody in a phage display vector. As nanobody repertoires usually undergo in vivo affinity maturation processes during the immunization process, the nanobodies derived from the immune library will generally possess higher affinities and specificities toward the antigens of interest if compared to those obtained from the naïve library. The immune repertoires are used to isolate distinct nanobodies against particular antigens, e.g., cell surface antigens of pathogen or tumor markers.

The benefits of using nanobody immunized library service include:

  • More likely to obtain desired nanobodies against particular antigens
  • Able to recognize novel epitopes
  • Greater affinity and specificity

Why use naïve library
service?

Naïve nanobody phage library is a valid alternative to the immunized nanobody phage library, and in light of the short turn-around time, the naïve nanobody library is by far the most used strategy for the selection of new antibodies. Naïve libraries are especially recommended for antigens with low immunogenicity, toxic, lethal, transmissible effects, or nonimmunogenic small molecular compounds.

The benefits of using nanobody naïve library service include:

  • Reduce lead times
  • Overcome immunogenicity issues
  • Minimization of animal use (no animal immunization is required)
  • Possibility of using the same antibody library in different projects (versatility)