Exosomes are natural carriers of proteins, lipids, DNA, miRNA, and IncRNA. There is increasing interest in manipulating the protein composition of exosomes using the exosome display technology. This technology is very versatile since soluble, membrane-bound, trans-membrane or multimeric antigens that are not naturally found on exosomes can now be efficiently expressed at their surface in a native conformation. To drive the development of membrane protein therapeutics, Creative Biolabs is utilizing the exosome display technology for generation and isolation of antibodies against different drug targets, notably including those difficult targets such as the G-protein coupled receptors (GPCRs).

Exosome Display of Different Proteins

Two modes of proteins can be transferred to exosomes. The first mode of transfer applies to soluble proteins and extracellular domains of receptors. Generally, the C1C2 domain of Lactadherin is used to address the proteins to the exosome surface. The second mode applies to full-length (transmembrane) membrane proteins. Due to the difficulties of obtaining purified soluble transmembrane proteins in their native conformation, exosomes have been used as a display platform to present and overexpress these proteins on exosomal surfaces. Exosome display of proteins offers many advantages, including:

• Provide a favorable microenvironment for membranes to take on their proper conformation, activity, and membrane distribution.
• Offer many possibilities to tailor exosomes with desirable functions.
• Represent a unique and cost-effective antigen presentation platform to enrich membrane proteins for antibody development.

Fig.1 Schematic of Exosome targeting strategy using the C1C2 domain of Lactadherin. (Delcayre, 2005)

ExoMAb Approach for Antibody Development against GPCRs

The application of Exosome Display to the generation of antibodies is called the ExoMAb approach. This approach applies to antibody induction and screening in situations where the antigen is either difficult to produce or poorly immunogenic. Besides, the induction of antibody responses upon immunization with antigen bound to exosomes may be achieved while maintaining the scale of immunogen preparation to a minimum due to the potent adjuvant activity of exosomes. Moreover, ExoMAb technology does not require tedious and costly antigen purification, which is done along with the purification of exosomes under non-denaturing conditions. This process involves 2 key steps:

• Recombinant exosomes bearing target antigens are generated, purified, and characterized, followed by immunization of animals (e.g., mice) to induce antibody responses.
• Labeled recombinant exosomes are used to screen and/or sort antibody repertoires to identify and isolate antibody-producing cells. Antibody repertories can be primary cells, hybridoma from immunized mice, or libraries of recombinant antibodies.

Fig.2 Schematic of ExoMAb approach. (Delcayre, 2005)

Features

• Custom-specific project designs that allow antibody development against different antigens, especially GPCRs
• Expert scientists and staff that work closely with customers to provide satisfying service support
• Streamlined services from consultation and project design, to product production and data interpretation
• Ensured high quality, consistent reproducibility, and timeliness of delivery
• Amenable to different downstream applications and research purposes

Scientists in Creative Biolabs have been worked on exosome research for many years, especially specialized in exosome display for antibody production. We are confident for offering the best exosome antibody development services based on state-of-art exosome display technique. If you are interested in any of our services, contact us and start the conversation.

Reference:

1. Delcayre, A.; et al. Exosome Display technology: applications to the development of new diagnostics and therapeutics. Blood Cells Molecules & Diseases. 2005, 35(2):158-168.

• Exosome Display-based Protein Array Screen
• Exosome Display-based Targeted Delivery