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.

Biologics

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

Monoclonal Antibody Development

Chicken IgY monoclonal antibody

Chicken IgY antibodies are the avian equivalent of mammalian IgG antibodies. Compared to mammalian IgG antibodies, chicken IgY antibodies have higher affinity, less cross-reactivity and higher specificity— rendering chicken IgY antibodies more valuable in laboratory experiments and diagnostic assays.


Unlike other chicken monoclonal antibody service providers, Exonbio uses SPIN® technology to isolate the antigen specific plasma cells, analyze and clone the native antibody heavy and light chain pairs from single plasma cells. This process significantly increases the affinity and diversifies the antibodies obtained.

  • Higher affinity and broader diversity
  • Better antigenicity for mammalian antigens
  • Higher specificity and low cross-reactivity

Chicken Immunization

While mice are the animal of choice for making monoclonal antibodies and the rabbit is typically used for making polyclonal antibodies, during the past thirty years some mammalian antigens fail to induce an immune response in either rodents or rabbits especially in the case of highly conserved proteins. In cases where an immune response was lacking in immunized mice or rabbits, investigators have turned to the chicken, particularly when polyclonal antibody preparation fails to meet the experimental objectives.

Additionally, one of the reasons chickens have not gained popularity as an immunizaztion animal is the lack of robust technology for making chicken monoclonal antibodies. The hybridoma technology for producing monoclonal antibodies was developed for mice by G. Kohler and C. Milstein in 1975. In 1995, Katherine Knight and her colleagues, at Loyola University of Chicago, succeeded in developing a rabbit hybridoma technology for developing the rabbit monoclonal antibody. Until recent years, Phage Display technology has been utilized in the field and made chicken monoclonal antibody possible.

SPIN® Technology or Phage Display

Currently, phage display has become an important approach for the development of monoclonal antibodies from both immune and nonimmune sources. This approach allows for the rapid selection of monoclonal antibodies without the restraints of the conventional hybridoma approach. However, the use of phage display technology for chicken monoclonal antibody development is limited by its effectiveness. The mixture of heavy chains and light chains from different B cells exponentially increased the size of the library and clone numbers required to screening. The strong bias induced by amplification of phage preferences in bacteria often mask the target-binding selection and generate nonfunctional parasitic clones.

To avoid the defect of phage display, we developed a SPIN® (Single Plasma Cell Interrogation) Technology. Compared to phage display, SPIN® for chicken monoclonal antibody production is more robust and much less bias in selection. Therefore, antibodies generated by SPIN® has higher affinity, as well as high diversity.

Avian Immune System

The avian immune system resembles that of mammals since both evolved from a common reptilian ancestor and have inherited many commonalities. They have also developed a number of different strategies that are unique to birds. Most avian immunology research has been carried out on the domestic chicken, Gallus gallus domesticus. Chickens have lymphoid tissues, B cells, T cells, cytokines and chemokines like many other animals. In addition, they can also have tumors, immune deficiency and autoimmune diseases.

Gene Rearrangement and Gene Conversion

Chickens, like mammals have both humoral and cell mediated arms of the adaptive immune system (Erf 2004; Scott 2004; Sharma 1991). The bursa of Fabricius is essential for normal B cell development and humoral immunity in birds, as evident in the pivotal work by Glick et al., 1956. These precursor B cells have already rearranged their immunoglobulin genes prior to entering the bursa. Compared to mammalian species, the chicken contains a very limited number of variable genes. In contrast with humans and mice, chickens use a process termed gene conversion to create antibody diversity, where the variable heavy and light chains are replaced with upstream psedugenes (Benatar et al., 1992), which is the same mechanism as the rabbit immunogenetics. While only one variable (V) light chain, one joining (J) light chain, one V heavy chain, one J heavy chain, and sixteen D heavy chains are initially available for gene rearrangement, approximately 25 V light and 80 V heavy pseudogenes can be inserted to create antibody diversity, which occurs in the bursa.

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