Your Outsourcing Partner for Protein Research and Production Services

To meet the needs of our clients, Exon provides protein characterization of our expressed protein to insure the quality of recombinant protein.

Recombinant Protein Expression

Exon BioSystems is a protein contract research and production services company specializing in recombinant protein expression, protein purification, and protein characterization.

Antibody Engineering

Additional areas of expertise include assay development of G-protein coupled receptor, recombinant vaccine development and recombinant antibody production.


Exon BioSystems is a protein contract research and production services company specializing in recombinant protein expression, protein purification, and protein characterization.

Monoclonal Antibody Development

Llama Monoclonal Antibody

Llamas antibodies are now offering new insights into many different aspects of research. Due to their large sizes, typical antibodies are not the best choice for in vivo research. Scientists sought out a means of expanding the limited applications in basic research, therapeutics, and diagnostics. Thus, antibodies, camels, and llamas were some of the focuses due to their smaller size. Smaller sized antibodies are beneficial for tissue penetration.

Much of research is going toward the development and implementation of many vaccines today. Generally, vaccines work by inducing an immune response, characterized by neutralizing antibodies against a certain pathogen. New studies show that the llama antibodies have actually destroyed a wide range of circulating HIV viruses.

But why llamas?

Llama antibodies have all the characteristics expected to see in more typically used antibodies, such as those found in human antibodies, but also include a group of smaller antibodies that don't correspond to anything seen in such studies before. Raymond Hamers and Cecil Casterman delived further into this discovery, believing that these antibodies were not degraded forms of larger antibodies, but were special in their own right after realizing that these antibodies could hold their own. Eventually, they would come to discover that the camels and their antibodies produces specific HC, or heavy chain, antibodies against substances.

It turns out that the HC antibodies recognize a wide range of antigens while also interacting with them at various epitopes. HC antibodies raised against small enzymes such as lysozyme or ribonuclease can penetrate the active site providing a potent inhibitor for the enzyme. The smaller size of llama antibodies allows them to be more accessible.

The difference between llama antibodies and typical antibodies. A typical antibody is picture on the left and a llama antibody on the right. The VHH region is the single domain antibody, or sdAb.

This all stems from the study that conventional antibody, the antigen recognition is provided by a heavy chain and a light chain. The HC antibodies bond in narrow regions of a molecule. This is the reason for it being able to reach parts of a molecule that other antibodies can't. With camel antibodies, the DNA for the binding domain (V-region) can be isolated and transformed into bacteria, effectively manufacturing a singular domain antibody.

The camel antibody allows one to easily enter into a localized tumor. The small size of the antibodies allows for a wide variety of benefits when utilizing them. For instance, they can be utilized within the cell itself, due to its smaller nature, entering the cell through the cell membrane.

With our novel Single Plasma Cell Interrogation (SPIN®) Technology, single domain antibodies are isolated from individual plasma cells of immunized Llama and are expressed in mammalian cells allowing them to be functionally analyzed. This technique leads to broad epitope coverage and high affinity antibodies allowing material to be used in the most efficient way possible.

Advantages of SPIN® technology

1. High affinity: Isolating Plasma cells, the most mature and terminal differentiated B cells for library construction ensure high antibody affinity.

2. Straight forward: Direct expression in mammalian cells and screening of antibody individually allows for straight forward results and analysis.

3. Broad epitope converage: Assays are made functional by screening targets directly using indirect ELISAs

Llama IgG Gene Structure

The Arabian camel (Camelus dromedarius) and the llama (Lama glama) have three IgG subclasses: the conventional IgG1 and the non-conventional IgG2 and IgG3.

What makes IgG1 different from its two counterparts? There's a splicing defect in the CH1 exon which causes the CH1 domain to be absent in both the gamma 2 and gamma 3 chains. This leads to a striking difference from IgG2: a lack of light chains in IgG2 and IgG3.

From The IMGT Biotechnology page (

Advantages of llama VHH single domain antibodies:

1. Accessibility: VHH single domain antibodies are only 15kD in size, compared to about 150kD for typical immunoglobulins. The smaller size makes it easier to penetrate tissues and gives them access to “hidden” epitopes while readily crossing the blood-brain barrier.

2. Stability: VHH antibodies are extremely stable and resistant to both high acidity and high temperature. They're even able to fold back into a functional protein after denaturation.

3. Solubility: Single domain antibodies have increased hydrophobicity, which in turn leads to a very high solubility.

4. Engineering: VHH antibodies are pure monomers, offering fast-track lead optimization and engineering to bi-specific nanobodies.

Procedure Description
Phase I Immunization Immunization of one Llama on standard protocol ELISA to assess the titer
Phase II Plasma Cell Isolation SPIN® technology isolates plasma cells. ONLY the terminal differentiated plasma cells with the most mature antibodies will be applied for library construction
Phase III Single Domain Library Construction Single domain antibody genes are amplified to construct small libraries
Phase IV Expression and Screening Directly screening individual single domain antibodies using ELISA or functional assays make antibodies suitable for downstream work.
Phase V Production Efficient HEK293 or CHO cell expression

For more information: