Generation and Characterization of Rat Monoclonal Antibodies Against Epidermal Growth Factor Receptor

A primer set for the rapid isolation of scFv fragments against cell surface antigens from immunised rats

Antibody phage display is a powerful platform for discovery of clinically applicable high affinity monoclonal antibodies against a broad range of targets. Libraries generated from immunized animals offer the advantage of in vivo affinity-maturation of V regions prior to library generation. Despite advantages, few studies have described isolation of antibodies from rats using immune phage display. In our study, we describe a novel primer set, covering the full rat heavy chain variable and kappa light chain variable regions repertoire for the generation of an unbiased immune libraries. Since the immune repertoire of rats is poorly understood, we first performed a deep sequencing analysis of the V(D)J regions of VH and VLK genes, demonstrating the high abundance of IGVH2 and IGVH5 families for VH and IGVLK12 and IGVLK22 for VLK. The comparison of gene's family usage in naïve rats have been used to validate the frequency's distribution of the primer set, confirming the absence of PCR-based biases. The primers were used to generate and assemble a phage display library from human CD160-vaccinated rats. CD160 represents a valid therapeutic target as it has been shown to be expressed on chronic lymphocytic leukaemia cells and on the surface of newly formed vessels. We utilised a novel phage display panning strategy to isolate a high affinity pool (KD range: 0.399-233 nM) of CD160 targeting monoclonal antibodies. Subsequently, identified binders were tested for function as third generation Chimeric Antigen Receptors (CAR) T cells demonstrating specific cytolytic activity. Our novel primer set coupled with a streamlined strategy for phage display panning enable the rapid isolation and identification of high affinity antibodies from immunised rats. The therapeutic utility of these antibodies was demonstrated in CAR format.

Generation of the Rat Monoclonal Antibody Against the Extracellular Domain of Human CD63 by DNA Immunization

Human cluster of differentiation 63 (hCD63) is one of the tetraspanin receptors that is abundant on the surface of exosomes. Exosomes are involved in cell-to-cell communication, including from cancer cells to normal cells. It is very important to detect exosomes as a marker for the diagnosis of various diseases. In this study, we report the generation and characterization of a monoclonal antibody (mAb) against the extracellular domain of hCD63 using DNA immunization. This mAb, clone 1C8-2B11, exhibits high performance for use in immunofluorescence and flow cytometry, and it has 10-fold higher affinity than the control antibody that is commercially available. mAb 1C8-2B11 has great potential to be a tool for research and clinical diagnosis.