Recombinant antibodies for in vivo applications

 

Matej Zábrady1,2, Vendula Hrdinová2, Bruno Müller3, Udo Conrad4, Jan Hejátko2, Lubomír Janda1

 

1Center for Structural Biology, Division of Biomolecular NMR Spectroscopy, Central European Institute of Technology, Masaryk University, CZ-62500 Brno, Czech Republic

2Functional Genomics and Proteomics of Plants, Central European Institute of Technology, Masaryk University, CZ-62500 Brno, Czech Republic

3Institute of Plant Biology, Zurich-Basel Plant Science Center, University of Zurich, CH-8008 Zurich, Switzerland

4Department of Molecular Genetics, Leibniz-Institute of Plant Genetics and Crop Plant Research (IPK) Corrensstr. 3, D-06466 Gatersleben

 

Interactions between biomolecules constitute the core of biological functions. In protein–protein interactions, specificity plays a key role and many proteins have evolved into extraordinarily precise molecular machines. The multistep phosphorylation pathway of the cytokinin signaling in plants involves promiscuous protein-protein interactions, allowing the plasticity of the plant-cell response to environmental and developmental stimuli. We have developed a recombinant antibody which is able to bind to a specific protein from the phosphorylation pathway in vivo. This protein cannot be phosphorylated in the presence of the recombinant antibody and the signal is not delivered to the nucleus to commit the reaction of the plant. To accomplish a successful selection of the recombinant antibody, we have developed an in vivo selection method. This method allows targeted selection of recombinant antibodies with a specific activity. During the development of our method, we came to these conclusions. In vivo selection process is important, because the stability of the recombinant antibody in the reducing environment of the plant cell is difficult to predict. Additionally, the uncertainty of the correct form of the antigen produced by heterologous expression introduces another variable, which might result in the unsuccessful selection of a correct recombinant antibody.