Do you want to develop a monoclonal antibody conserving its native properties with maximized developability? Our single B-cell sorting service provides highly affine antibodies with natural VH and VL pairing and maximum B-cell diversity. We guarantee you receive a minimum of 3 antibody sequences within a maximum of 2 months from animal immunization to antibody screening thanks to our high throughput single B-cell antibody technologies platform.

Workflow of single B-cell screening


  • Antigen checking by SDS-PAGE
    (Antigen provided by You or designed by us)
  • Rabbit immunization
    4-6 rounds of injections using an optimized protocol
    Immunization is performed on Rabbits


4-6 weeks

Single B-cell sorting and screening

  • Isolation of PBMCs and spleen lymphocytes
  • Fluorescence-Activated B-Cell Sorting (FACS) antigen-specific single B-cells sorted (1cell/well)
  • B-cell culture and supernatant screening against antigen in ELISA


2-3 weeks

Recombinant rabbit antibody (IgG) production and screening

  • Best positive clones sequencing
  • Transient expression into high performance proprietary XtenCHO™
  • B-cell culture and supernatant screening against antigen in ELISA


2 weeks

Want to test additional clones?

Want to test additional ELISA?

Additional services

  • ELISA for positive/negative screening: (Against one specific peptide/protein/small molecule- cross reactivity profiling)
  • Competitive ELISA: (To identify clones with blocking/ neutralizing activity)

How Much Does Single B Cell Sorting Cost?

ProteoGenix’s B cell sorting services offer a flexible and customizable pricing structure to cater to your individual needs. Our prices start at a few thousand euros with pricing depending on the number of specific requirements for each project. The pricing is largely influenced by the number of antibody sequences to be analyzed and the scope of the service purchased.

We also offer the option for customers to enhance their single B cell sorting experience with supplementary services. These additional services include ELISA for positive/negative screening against specific peptides, proteins, or small molecules, as well as cross-reactivity profiling. Furthermore, our Competitive ELISA service enables the identification of clones with blocking or neutralizing activity, providing invaluable insights for therapeutic development.

Building a custom antibody using B cell isolation is a valuable investment that yields long-term cost savings. By precisely selecting high-affinity antibody clones early in the development process, it minimizes resources spent on less promising candidates. The targeted approach reduces downstream costs, ensuring efficient large-scale production and accelerating the path to a successful therapeutic, resulting in substantial savings in the long run.

At ProteoGenix, we understand the uniqueness of each project and aim to provide tailored solutions for our clients. Our team of experts works closely with customers to evaluate their specific needs and propose the most appropriate services within their budget. With our transparent and ranking-based pricing approach, customers can confidently choose the services that best align with their research objectives, ultimately ensuring the success of their single B cell sorting projects.

How Long Does Single B Cell Isolation Take?

At ProteoGenix, our single B cell antibody technologies are designed for rapid and efficient results. The customer can get his antibody within only 8 weeks, ensuring a quick turnaround for their project.

We are proud to introduce our new immunization protocol that offers significant time savings, allowing us to complete the process 50% faster than our competitors. Immunization delays have been reduced from the typical 6-8 weeks to just 4-6 weeks, further streamlining the B cell sorting timeline and providing customers with even faster access to their desired antibody sequences.

Can I patent my antibody sequence after B cell sorting?

You can patent your antibody sequence that is delivered from our B cell sorting service. We believe in providing our customers with full ownership of their antibody sequences, giving you the freedom and protection to secure intellectual property rights for your valuable discoveries.

With our B cell sorting services, you can confidently pursue patent applications and protect the innovative potential of your custom antibodies, ensuring their exclusivity and commercial value in the market.

What are the advantages of single B-cell sorting antibody technology?

Single B-cell sequencing is an efficient monoclonal antibody development and screening strategy whose principle is based on the amplification of genes encoding the VH and VL region from B-cells directly. This technology presents several advantages making it a very useful approach for antibody biology understanding and for antibody use in clinical essays. Among these advantages, single B-cell sorting is characterized by:

  • High throughput B-cell sorting – Single B-cell sequencing integrates high throughput platforms for antibody selection which allows performing different screenings in a highly efficient manner.
  • Native monoclonal antibody preservation – The main advantage of single B-cell sorting technology is that it preserves the native VH and VL pairing, two domains of monoclonal antibodies critical for antigen recognition and binding. Thus, natural cognate pairing is maintained and the development of antibodies with high affinity, stability, and specificity is guaranteed.
  • Rare antibodies identification – Some antibodies with relevant therapeutic properties are hard to identify. Thanks to the single B-cell screening approach, some rare antibodies are identified directly from B-cells and this limits the risks of unnatural pairing resulting from in vitro screening. Moreover, this approach is ideal for the discovery of rare antibodies against challenging targets such as conformational epitopes.
  • Antibody diversity maximization – Thanks to the highly sophisticated screening method, single-B cells are screened individually leading to a varied repertoire of monoclonal antibodies which increases the B cell diversity.
  • Higher efficiency and expedited timelines – Single B-cell screening is a very efficient technology characterized by an unprecedented single-cell resolution and an exceptionally rapid timeline saving months of work as a result of avoiding the cell fusion (hybridoma) and library construction (phage display) steps.
Pro Cons
  • High antibody affinity
  • Preservation of natural VH-VL pairing (positively impacts developability)
  • Cheap
  • High loss of diversity due to low efficiency of cell fusion
  • Limited to rodents as myeloma cells not efficient in other species
  • Humanization needed
  • Not adapted to antigens with low immunogenicity and/or toxicity
  • Animal use
Phage Display
  • No species restriction
  • No need for humanization thanks to fully human libraries & humanized mice
  • Maximized diversity due to random VH-VL pairing
  • High-throughput screening allowing identification of multiple binders
  • Adapted to antigens with low immunogenicity and/or toxicity
  • Very fast
  • No animal use thanks to premade libraries
  • Non-natural VH-VL pairing can negatively impact developability
  • Potential bias due to phage particle
  • Low/medium antibody affinity due to lack of immunizations (naïve libraries)
  • High affinity antibodies expensive & long to develop as require custom immune library construction
Single B-Cell Sorting
  • No species restriction
  • High antibody affinity
  • Preservation of natural VH-VL pairing
  • HHigh-throughput screening
  • Best for discovery of rare antibodies against challenging targets (e.g. conformational epitopes) with maximized developability
  • Not adapted to antigens with low immunogenicity and/or toxicit
  • Animal use

B cell sorting and its significance in various research and clinical applications

Single B cell isolation plays a vital role in diverse research and clinical applications, facilitating the isolation of pure B cell populations for in-depth studies.

Understanding immune responses, uncovering novel antibodies, and developing immunotherapies heavily rely on the precision and efficiency of this technique. By isolating specific B cell subsets, researchers gain valuable insights into immune system functioning, enabling advancements in vaccine development, autoimmune disease research, understanding immunodeficiencies, allergy research, infectious diseases, and cancer immunotherapy.

The ability to extract high-affinity antibodies directly from B cells expedites antibody discovery, accelerating the development of potential therapeutics. With its broad applications across immunology and medicine, single B cell antibody technologies stand as powerful tools, propelling breakthroughs in numerous disciplines.

The role of B-cells in antibody production

B-cells are a type of white blood cell commonly called a B lymphocyte. They function by providing organisms with adaptive immunity to infections, a subcomponent of the humoral immune response. Specifically, the role of a B-cell is to produce antibody molecules that are either cell membrane-bound B-cell receptors or soluble immunoglobulins.
The B-cell receptor, expressed by naive and memory B-cells, facilitates the interaction between B cells and foreign antigens. After encountering a foreign antigen, a naive or memory B-cell undergoes activation, leading to its proliferation and transformation into a specialized cell called a plasma cell, which secretes antibodies.
Each antibody secreted by a single activated B-cell has a monovalent affinity toward a specific antigen. This means the antibodies bind a single epitope, the part of an antigen recognized by an antibody. The monovalent antibodies secreted from a single B-cell clonal lineage are called monoclonal antibodies. Monoclonal antibodies comprise four polypeptide chains, two identical heavy chains, and two identical light chains. The heavy and light chains are held together by several disulfide bonds that help the polypeptide chains fold to form a Y-shaped tetramer. Biomedical scientists use these epitope-specific antibodies to detect the presence of specific macromolecules and by physicians to treat cancer, autoimmune diseases, and genetic disorders.

What is single B-cell sorting

Single B-cell sorting is used to isolate individual B-cells to assess how well the secreted antibodies bind a target antigen. Traditional methods of monoclonal antibody development did not involve the isolation and cell culture of single B cells. However, isolating individual B-cells and characterizing the secreted monoclonal antibodies helps scientists capture diverse antibody repertoires improving the probability of discovering rare antibodies with therapeutic potential.

From B-cell Isolation to custom antibody production

The first step in B-cell isolation involves the immunization of rabbits against a target antigen. This step is important for stimulating the differentiation of naive B-cells into antigen-specific antibody-producing cells.
The success of any B-cell isolation project is critically dependent on the quality of the antigen used in the immunization process. For this reason, ProteoGenix can design, synthesize, isolate, and purify each antigen used in our rabbit immunization protocol. This guarantees that specific quality, purity, and concentration standards are achieved for the success of each B-cell isolation project.

Isolation of antigen-specific B-cells by FACS

Following several rounds of immunization, blood PBMCs, and spleens are collected so antigen-specific B-cells can be isolated. This B-cell isolation step occurs between 6 and 8 weeks after the first rounds of immunization.
Single B-cells are sorted by incubating the cells with a biotin-conjugated target antigen followed by incubation with a streptavidin-conjugated fluorophore. The resulting fluorescently labeled antigen-specific B-cells are separated by FACS into individual wells (1 cell per well) of a tissue culture plate. The secreted antibodies are screened to detect antigen binding capacity by ELISA. This process takes between two and three weeks to complete.

Cloning and expressing antibody genes from isolated B-cells

Once we identify the monoclonal antibodies with the highest target antigen affinity, we clone the corresponding VH and VL gene segments and transiently express the gene products using our proprietary high-performance XtenCHO cells.
As an additional service, ProteoGenix can identify clones with the ability to neutralize specific targets or assess the crossreactivity profile of a specific antibody.

Single B-cell sorting is optimal for challenging antibody targets

Traditional monoclonal antibody technology involves creating a hybrid cell line by fusing B-cells from immunized mice with an immortal B-cell myeloma cell line. The resulting fused cells are referred to as hybridoma cells because they are a hybrid between a healthy B-cell and a transformed B-cell. Hybridoma cells are isolated and separated into individual wells to assess the antigen-binding potential of the secreted antibodies.
The process of B-cell fusion is inefficient. Many B-cells are lost during this process, decreasing the probability of discovering a rare antibody that binds difficult-to-target epitopes. In contrast, our single B-cell screening method maximizes the B-cell isolation and characterization of antibodies secreted from B-cells increasing the probability of discovering rare antibodies that bind a target antigen with precision.

The challenges of single B-cell isolation

Picking the right team of antibody experts to isolate single B-cells for monoclonal antibody production is critically important given the numerous challenges involved in B-cell isolation. First, the ability to make custom antigens, including conformation-dependent antigens, is critical to success. These antigens are not only necessary for the immunization steps but also for the isolation of antigen-specific B-cells by FACS. The synthesized antigen must be a specific purity and concentration for optimal success.
Successful B-cell isolation also requires an array of properly calibrated precision instruments to isolate B-cells and verify antigen binding capacity. In addition, the ability to culture naive and memory B-cells requires well-optimized conditions to promote cell proliferation and maintain cell viability. These parameters alone require years of optimization and expertise.
At ProteoGenix, our antibody experts have an average of 25 years of experience in antigen synthesis and antibody development. With 3 therapeutic antibodies on the market and over 30 antibodies in the preclinical and clinical phases of investigation, we know how to make high-performing antibodies for our clients. Book a call with one of our antibody experts to learn how we can help you accelerate your project needs.