Design and Testing of a Thermostable Platform for Multimerization of Single Domain Antibodies

Abstract : Immunoaffinity reagents are used to detect biothreat agents, but one limitation is the thermal sensitivity of standard antibodies. The abilities to maintain recognition and remain thermostable provide enhanced capability for fielding immunoaffinity-based sensors. One technology capable of delivering thermostability is single domain antibodies. These molecules have substantial thermostability, but affinity is often reduced as compared to monoclonal antibodies. Using recombination, we created single domain antibodies (sdAb s) in a thermostable platform and used the sequences for two sdAb s that recognized unique epitopes on the ricin A chain. We tethered them to a platform on the basis of the structural maintenance of chromosome proteins. The engineered molecules were characterized by surface plasmon resonance, and the thermoplasticity of the molecules was tested up to 55 C. The engineered constructs did bind to ricin. They demonstrated an avidity increase over the sdAb s. The heated sample maintained half of the biological activity. These results indicate that by multimerizing the sdAb s on a thermostable platform, it is possible to increase avidity and maintain some thermoplasticity. This platform allows for a plug and play approach to multimerization of sdAb s, and it has the potential for application to signaling and mitigating activities.