cDNA Immunization of Mice, Rats, and Hamsters

Genetic immunization has been useful in vaccine technology and can also be used to generate immune responses to novel proteins. It is particularly useful when a properly folded protein is difficult to isolate or make in recombinant form and the required antibody must recognize a conformational epitope. Injecting cDNA allows the protein to be expressed in native form by the animal's own cells in vivo and then presented to the immune system. Genetic immunization is most effective for the generation of antibodies if the cDNA encodes for secreted or cell-surface proteins to make them accessible to the immune system. It also has been successful in generating antibody responses to difficult protein targets such as G-coupled protein receptors, ion channel proteins, and other multiple membrane-spanning proteins. High-affinity antibodies tend to be favored because the proteins are expressed at low levels and are constantly present for presentation to the immune system. In addition, several months can be saved obtaining sufficient amounts of properly folded, soluble recombinant protein or high-expressing transfected cells.