DNA immunization using in vivo electroporation for generating monoclonal antibodies Against Mouse IL-9R

Membrane proteins such as cytokine receptors and G protein-coupled receptors can be drug targets. Recently, we have generated specific monoclonal antibodies (mAbs) against the mouse IL-9 receptor (IL-9R) and found that IL-9R on memory B cells have critical roles in T-dependent immune response. So far, most antibodies against cell surface proteins have been generated by immunization of animals with recombinant proteins produced in Escherichia coli (E. coli) or peptides derived from the protein. However, such antibodies often fail to recognize native proteins on cell surfaces because these antigens lack posttranslational modification and natural protein conformations. To circumvent such problems, we have developed a mouse immunization method, the DNA-immunization utilizing hyaluronidase and E. coli GroEL. Herein, we report an application of the original mouse immunization method in rats to generate anti-mouse IL-9R mAbs which could react with the native form of mouse IL-9R on cell surfaces. Thus, we suggest that the DNA-immunization method is feasible for generating monoclonal antibodies against cell surface proteins in rats.